diff --git a/cores/c16/t65/T65.vhd b/cores/c16/t65/T65.vhd old mode 100644 new mode 100755 index 4a21d79..b9fa335 --- a/cores/c16/t65/T65.vhd +++ b/cores/c16/t65/T65.vhd @@ -1,19 +1,65 @@ -- **** -- T65(b) core. In an effort to merge and maintain bug fixes .... -- +-- Ver 313 WoS January 2015 +-- Fixed issue that NMI has to be first if issued the same time as a BRK instruction is latched in +-- Now all Lorenz CPU tests on FPGAARCADE C64 core (sources used: SVN version 1021) are OK! :D :D :D +-- This is just a starting point to go for optimizations and detailed fixes (the Lorenz test can't find) +-- +-- Ver 312 WoS January 2015 +-- Undoc opcode timing fixes for $B3 (LAX iy) and $BB (LAS ay) +-- Added comments in MCode section to find handling of individual opcodes more easily +-- All "basic" Lorenz instruction test (individual functional checks, CPUTIMING check) work now with +-- actual FPGAARCADE C64 core (sources used: SVN version 1021). +-- +-- Ver 305, 306, 307, 308, 309, 310, 311 WoS January 2015 +-- Undoc opcode fixes (now all Lorenz test on instruction functionality working, except timing issues on $B3 and $BB): +-- SAX opcode +-- SHA opcode +-- SHX opcode +-- SHY opcode +-- SHS opcode +-- LAS opcode +-- alternate SBC opcode +-- fixed NOP with immediate param (caused Lorenz trap test to fail) +-- IRQ and NMI timing fixes (in conjuction with branches) +-- +-- Ver 304 WoS December 2014 +-- Undoc opcode fixes: +-- ARR opcode +-- ANE/XAA opcode +-- Corrected issue with NMI/IRQ prio (when asserted the same time) +-- +-- Ver 303 ost(ML) July 2014 +-- (Sorry for some scratchpad comments that may make little sense) +-- Mods and some 6502 undocumented instructions. +-- Not correct opcodes acc. to Lorenz tests (incomplete list): +-- NOPN (nop) +-- NOPZX (nop + byte 172) +-- NOPAX (nop + word da ... da: byte 0) +-- ASOZ (byte $07 + byte 172) +-- +-- Ver 303,302 WoS April 2014 +-- Bugfixes for NMI from foft +-- Bugfix for BRK command (and its special flag) +-- +-- Ver 300,301 WoS January 2014 +-- More merging +-- Bugfixes by ehenciak added, started tidyup *bust* -- --- Ver 301 more merging --- Ver 300 Bugfixes by ehenciak added, started tidyup *bust* -- MikeJ March 2005 --- Latest version from www.fpgaarcade.com (original www.opencores.org) --- +-- Latest version from www.fpgaarcade.com (original www.opencores.org) -- **** -- -- 65xx compatible microprocessor core -- --- Version : 0246 +-- FPGAARCADE SVN: $Id: T65.vhd 1347 2015-05-27 20:07:34Z wolfgang.scherr $ -- --- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org) +-- Copyright (c) 2002...2015 +-- Daniel Wallner (jesus opencores org) +-- Mike Johnson (mikej fpgaarcade com) +-- Wolfgang Scherr (WoS pin4 at> +-- Morten Leikvoll () -- -- All rights reserved -- @@ -43,22 +89,37 @@ -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- --- Please report bugs to the author, but before you do so, please +-- Please report bugs to the author(s), but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- --- The latest version of this file can be found at: --- http://www.opencores.org/cvsweb.shtml/t65/ +-- ----- IMPORTANT NOTES ----- -- --- Limitations : +-- Limitations: +-- 65C02 and 65C816 modes are incomplete (and definitely untested after all 6502 undoc fixes) +-- 65C02 supported : inc, dec, phx, plx, phy, ply +-- 65D02 missing : bra, ora, lda, cmp, sbc, tsb*2, trb*2, stz*2, bit*2, wai, stp, jmp, bbr*8, bbs*8 +-- Some interface signals behave incorrect +-- NMI interrupt handling not nice, needs further rework (to cycle-based encoding). -- --- 65C02 and 65C816 modes are incomplete --- Undocumented instructions are not supported --- Some interface signals behaves incorrect +-- Usage: +-- The enable signal allows clock gating / throttling without using the ready signal. +-- Set it to constant '1' when using the Clk input as the CPU clock directly. -- --- File history : +-- TAKE CARE you route the DO signal back to the DI signal while R_W_n='0', +-- otherwise some undocumented opcodes won't work correctly. +-- EXAMPLE: +-- CPU : entity work.T65 +-- port map ( +-- R_W_n => cpu_rwn_s, +-- [....all other ports....] +-- DI => cpu_din_s, +-- DO => cpu_dout_s +-- ); +-- cpu_din_s <= cpu_dout_s when cpu_rwn_s='0' else +-- [....other sources from peripherals and memories...] -- --- 0246 : First release +-- ----- IMPORTANT NOTES ----- -- library IEEE; @@ -66,348 +127,365 @@ library IEEE; use IEEE.numeric_std.all; use work.T65_Pack.all; --- ehenciak 2-23-2005 : Added the enable signal so that one doesn't have to use --- the ready signal to limit the CPU. entity T65 is - port( - Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65C816 - Res_n : in std_logic; - Enable : in std_logic; - Clk : in std_logic; - Rdy : in std_logic; - Abort_n : in std_logic; - IRQ_n : in std_logic; - NMI_n : in std_logic; - SO_n : in std_logic; - R_W_n : out std_logic; - Sync : out std_logic; - EF : out std_logic; - MF : out std_logic; - XF : out std_logic; - ML_n : out std_logic; - VP_n : out std_logic; - VDA : out std_logic; - VPA : out std_logic; - A : out std_logic_vector(23 downto 0); - DI : in std_logic_vector(7 downto 0); - DO : out std_logic_vector(7 downto 0) - ); + port( + Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65C816 + Res_n : in std_logic; + Enable : in std_logic; + Clk : in std_logic; + Rdy : in std_logic; + Abort_n : in std_logic; + IRQ_n : in std_logic; + NMI_n : in std_logic; + SO_n : in std_logic; + R_W_n : out std_logic; + Sync : out std_logic; + EF : out std_logic; + MF : out std_logic; + XF : out std_logic; + ML_n : out std_logic; + VP_n : out std_logic; + VDA : out std_logic; + VPA : out std_logic; + A : out std_logic_vector(23 downto 0); + DI : in std_logic_vector(7 downto 0); + DO : out std_logic_vector(7 downto 0); + -- 6502 registers (MSB) PC, SP, P, Y, X, A (LSB) + Regs : out std_logic_vector(63 downto 0); + DEBUG : out T_t65_dbg + ); end T65; architecture rtl of T65 is - -- Registers - signal ABC, X, Y, D : std_logic_vector(15 downto 0); - signal P, AD, DL : std_logic_vector(7 downto 0) := x"00"; - signal BAH : std_logic_vector(7 downto 0); - signal BAL : std_logic_vector(8 downto 0); - signal PBR : std_logic_vector(7 downto 0); - signal DBR : std_logic_vector(7 downto 0); - signal PC : unsigned(15 downto 0); - signal S : unsigned(15 downto 0); - signal EF_i : std_logic; - signal MF_i : std_logic; - signal XF_i : std_logic; + -- Registers + signal ABC, X, Y : std_logic_vector(15 downto 0); + signal P, AD, DL : std_logic_vector(7 downto 0) := x"00"; + signal PwithB : std_logic_vector(7 downto 0);--ML:New way to push P with correct B state to stack + signal BAH : std_logic_vector(7 downto 0); + signal BAL : std_logic_vector(8 downto 0); + signal PBR : std_logic_vector(7 downto 0); + signal DBR : std_logic_vector(7 downto 0); + signal PC : unsigned(15 downto 0); + signal S : unsigned(15 downto 0); + signal EF_i : std_logic; + signal MF_i : std_logic; + signal XF_i : std_logic; - signal IR : std_logic_vector(7 downto 0); - signal MCycle : std_logic_vector(2 downto 0); + signal IR : std_logic_vector(7 downto 0); + signal MCycle : std_logic_vector(2 downto 0); - signal Mode_r : std_logic_vector(1 downto 0); - signal ALU_Op_r : std_logic_vector(3 downto 0); - signal Write_Data_r : std_logic_vector(2 downto 0); - signal Set_Addr_To_r : std_logic_vector(1 downto 0); - signal PCAdder : unsigned(8 downto 0); + signal Mode_r : std_logic_vector(1 downto 0); + signal ALU_Op_r : T_ALU_Op; + signal Write_Data_r : T_Write_Data; + signal Set_Addr_To_r : T_Set_Addr_To; + signal PCAdder : unsigned(8 downto 0); - signal RstCycle : std_logic; - signal IRQCycle : std_logic; - signal NMICycle : std_logic; + signal RstCycle : std_logic; + signal IRQCycle : std_logic; + signal NMICycle : std_logic; - signal B_o : std_logic; - signal SO_n_o : std_logic; - signal IRQ_n_o : std_logic; - signal NMI_n_o : std_logic; - signal NMIAct : std_logic; + signal SO_n_o : std_logic; + signal IRQ_n_o : std_logic; + signal NMI_n_o : std_logic; + signal NMIAct : std_logic; - signal Break : std_logic; + signal Break : std_logic; - -- ALU signals - signal BusA : std_logic_vector(7 downto 0); - signal BusA_r : std_logic_vector(7 downto 0); - signal BusB : std_logic_vector(7 downto 0); - signal ALU_Q : std_logic_vector(7 downto 0); - signal P_Out : std_logic_vector(7 downto 0); + -- ALU signals + signal BusA : std_logic_vector(7 downto 0); + signal BusA_r : std_logic_vector(7 downto 0); + signal BusB : std_logic_vector(7 downto 0); + signal BusB_r : std_logic_vector(7 downto 0); + signal ALU_Q : std_logic_vector(7 downto 0); + signal P_Out : std_logic_vector(7 downto 0); - -- Micro code outputs - signal LCycle : std_logic_vector(2 downto 0); - signal ALU_Op : std_logic_vector(3 downto 0); - signal Set_BusA_To : std_logic_vector(2 downto 0); - signal Set_Addr_To : std_logic_vector(1 downto 0); - signal Write_Data : std_logic_vector(2 downto 0); - signal Jump : std_logic_vector(1 downto 0); - signal BAAdd : std_logic_vector(1 downto 0); - signal BreakAtNA : std_logic; - signal ADAdd : std_logic; - signal AddY : std_logic; - signal PCAdd : std_logic; - signal Inc_S : std_logic; - signal Dec_S : std_logic; - signal LDA : std_logic; - signal LDP : std_logic; - signal LDX : std_logic; - signal LDY : std_logic; - signal LDS : std_logic; - signal LDDI : std_logic; - signal LDALU : std_logic; - signal LDAD : std_logic; - signal LDBAL : std_logic; - signal LDBAH : std_logic; - signal SaveP : std_logic; - signal Write : std_logic; + -- Micro code outputs + signal LCycle : std_logic_vector(2 downto 0); + signal ALU_Op : T_ALU_Op; + signal Set_BusA_To : T_Set_BusA_To; + signal Set_Addr_To : T_Set_Addr_To; + signal Write_Data : T_Write_Data; + signal Jump : std_logic_vector(1 downto 0); + signal BAAdd : std_logic_vector(1 downto 0); + signal BreakAtNA : std_logic; + signal ADAdd : std_logic; + signal AddY : std_logic; + signal PCAdd : std_logic; + signal Inc_S : std_logic; + signal Dec_S : std_logic; + signal LDA : std_logic; + signal LDP : std_logic; + signal LDX : std_logic; + signal LDY : std_logic; + signal LDS : std_logic; + signal LDDI : std_logic; + signal LDALU : std_logic; + signal LDAD : std_logic; + signal LDBAL : std_logic; + signal LDBAH : std_logic; + signal SaveP : std_logic; + signal Write : std_logic; - signal really_rdy : std_logic; - signal R_W_n_i : std_logic; + signal Res_n_i : std_logic; + signal Res_n_d : std_logic; + + signal really_rdy : std_logic; + signal WRn_i : std_logic; + + signal NMI_entered : std_logic; begin - -- ehenciak : gate Rdy with read/write to make an "OK, it's - -- really OK to stop the processor now if Rdy is - -- deasserted" signal - really_rdy <= Rdy or not(R_W_n_i); + -- gate Rdy with read/write to make an "OK, it's really OK to stop the processor + really_rdy <= Rdy or not(WRn_i); + Sync <= '1' when MCycle = "000" else '0'; + EF <= EF_i; + MF <= MF_i; + XF <= XF_i; + R_W_n <= WRn_i; + ML_n <= '0' when IR(7 downto 6) /= "10" and IR(2 downto 1) = "11" and MCycle(2 downto 1) /= "00" else '1'; + VP_n <= '0' when IRQCycle = '1' and (MCycle = "101" or MCycle = "110") else '1'; + VDA <= '1' when Set_Addr_To_r /= Set_Addr_To_PBR else '0'; + VPA <= '1' when Jump(1) = '0' else '0'; - -- ehenciak : Drive R_W_n_i off chip. - R_W_n <= R_W_n_i; + -- debugging signals + DEBUG.I <= IR; + DEBUG.A <= ABC(7 downto 0); + DEBUG.X <= X(7 downto 0); + DEBUG.Y <= Y(7 downto 0); + DEBUG.S <= std_logic_vector(S(7 downto 0)); + DEBUG.P <= P; - Sync <= '1' when MCycle = "000" else '0'; - EF <= EF_i; - MF <= MF_i; - XF <= XF_i; - ML_n <= '0' when IR(7 downto 6) /= "10" and IR(2 downto 1) = "11" and MCycle(2 downto 1) /= "00" else '1'; - VP_n <= '0' when IRQCycle = '1' and (MCycle = "101" or MCycle = "110") else '1'; - VDA <= '1' when Set_Addr_To_r /= "00" else '0'; -- Incorrect !!!!!!!!!!!! - VPA <= '1' when Jump(1) = '0' else '0'; -- Incorrect !!!!!!!!!!!! + Regs <= std_logic_vector(PC) & std_logic_vector(S)& P & Y(7 downto 0) & X(7 downto 0) & ABC(7 downto 0); - mcode : T65_MCode - port map( - Mode => Mode_r, - IR => IR, - MCycle => MCycle, - P => P, - LCycle => LCycle, - ALU_Op => ALU_Op, - Set_BusA_To => Set_BusA_To, - Set_Addr_To => Set_Addr_To, - Write_Data => Write_Data, - Jump => Jump, - BAAdd => BAAdd, - BreakAtNA => BreakAtNA, - ADAdd => ADAdd, - AddY => AddY, - PCAdd => PCAdd, - Inc_S => Inc_S, - Dec_S => Dec_S, - LDA => LDA, - LDP => LDP, - LDX => LDX, - LDY => LDY, - LDS => LDS, - LDDI => LDDI, - LDALU => LDALU, - LDAD => LDAD, - LDBAL => LDBAL, - LDBAH => LDBAH, - SaveP => SaveP, - Write => Write - ); + mcode : entity work.T65_MCode + port map( +--inputs + Mode => Mode_r, + IR => IR, + MCycle => MCycle, + P => P, +--outputs + LCycle => LCycle, + ALU_Op => ALU_Op, + Set_BusA_To => Set_BusA_To, + Set_Addr_To => Set_Addr_To, + Write_Data => Write_Data, + Jump => Jump, + BAAdd => BAAdd, + BreakAtNA => BreakAtNA, + ADAdd => ADAdd, + AddY => AddY, + PCAdd => PCAdd, + Inc_S => Inc_S, + Dec_S => Dec_S, + LDA => LDA, + LDP => LDP, + LDX => LDX, + LDY => LDY, + LDS => LDS, + LDDI => LDDI, + LDALU => LDALU, + LDAD => LDAD, + LDBAL => LDBAL, + LDBAH => LDBAH, + SaveP => SaveP, + Write => Write + ); - alu : T65_ALU - port map( - Mode => Mode_r, - Op => ALU_Op_r, - BusA => BusA_r, - BusB => BusB, - P_In => P, - P_Out => P_Out, - Q => ALU_Q - ); + alu : entity work.T65_ALU + port map( + Mode => Mode_r, + Op => ALU_Op_r, + BusA => BusA_r, + BusB => BusB, + P_In => P, + P_Out => P_Out, + Q => ALU_Q + ); - process (Res_n, Clk) - begin - if Res_n = '0' then - PC <= (others => '0'); -- Program Counter - IR <= "00000000"; - S <= (others => '0'); -- Dummy !!!!!!!!!!!!!!!!!!!!! - D <= (others => '0'); - PBR <= (others => '0'); - DBR <= (others => '0'); + -- the 65xx design requires at least two clock cycles before + -- starting its reset sequence (according to datasheet) + process (Res_n, Clk) + begin + if Res_n = '0' then + Res_n_i <= '0'; + Res_n_d <= '0'; + elsif Clk'event and Clk = '1' then + Res_n_i <= Res_n_d; + Res_n_d <= '1'; + end if; + end process; - Mode_r <= (others => '0'); - ALU_Op_r <= "1100"; - Write_Data_r <= "000"; - Set_Addr_To_r <= "00"; + process (Res_n_i, Clk) + begin + if Res_n_i = '0' then + PC <= (others => '0'); -- Program Counter + IR <= "00000000"; + S <= (others => '0'); -- Dummy + PBR <= (others => '0'); + DBR <= (others => '0'); - R_W_n_i <= '1'; - EF_i <= '1'; - MF_i <= '1'; - XF_i <= '1'; + Mode_r <= (others => '0'); + ALU_Op_r <= ALU_OP_BIT; + Write_Data_r <= Write_Data_DL; + Set_Addr_To_r <= Set_Addr_To_PBR; - elsif Clk'event and Clk = '1' then - if (Enable = '1') then - if (really_rdy = '1') then - R_W_n_i <= not Write or RstCycle; + WRn_i <= '1'; + EF_i <= '1'; + MF_i <= '1'; + XF_i <= '1'; - D <= (others => '1'); -- Dummy - PBR <= (others => '1'); -- Dummy - DBR <= (others => '1'); -- Dummy - EF_i <= '0'; -- Dummy - MF_i <= '0'; -- Dummy - XF_i <= '0'; -- Dummy + elsif Clk'event and Clk = '1' then + if (Enable = '1') then + if (really_rdy = '1') then + WRn_i <= not Write or RstCycle; - if MCycle = "000" then - Mode_r <= Mode; + PBR <= (others => '1'); -- Dummy + DBR <= (others => '1'); -- Dummy + EF_i <= '0'; -- Dummy + MF_i <= '0'; -- Dummy + XF_i <= '0'; -- Dummy - if IRQCycle = '0' and NMICycle = '0' then - PC <= PC + 1; - end if; + if MCycle = "000" then + Mode_r <= Mode; - if IRQCycle = '1' or NMICycle = '1' then - IR <= "00000000"; - else - IR <= DI; - end if; - end if; + if IRQCycle = '0' and NMICycle = '0' then + PC <= PC + 1; + end if; - ALU_Op_r <= ALU_Op; - Write_Data_r <= Write_Data; - if Break = '1' then - Set_Addr_To_r <= "00"; - else - Set_Addr_To_r <= Set_Addr_To; - end if; + if IRQCycle = '1' or NMICycle = '1' then + IR <= "00000000"; + else + IR <= DI; + end if; - if Inc_S = '1' then - S <= S + 1; - end if; - if Dec_S = '1' and RstCycle = '0' then - S <= S - 1; - end if; - if LDS = '1' then - S(7 downto 0) <= unsigned(ALU_Q); - end if; - - if IR = "00000000" and MCycle = "001" and IRQCycle = '0' and NMICycle = '0' then - PC <= PC + 1; - end if; - -- - -- jump control logic - -- - case Jump is - when "01" => - PC <= PC + 1; - - when "10" => - PC <= unsigned(DI & DL); - - when "11" => - if PCAdder(8) = '1' then - if DL(7) = '0' then - PC(15 downto 8) <= PC(15 downto 8) + 1; - else - PC(15 downto 8) <= PC(15 downto 8) - 1; - end if; - end if; - PC(7 downto 0) <= PCAdder(7 downto 0); - - when others => null; - end case; - end if; - end if; - end if; - end process; - - PCAdder <= resize(PC(7 downto 0),9) + resize(unsigned(DL(7) & DL),9) when PCAdd = '1' - else "0" & PC(7 downto 0); - - process (Clk) - begin - if Clk'event and Clk = '1' then - if (Enable = '1') then - if (really_rdy = '1') then - if MCycle = "000" then - if LDA = '1' then - ABC(7 downto 0) <= ALU_Q; - end if; - if LDX = '1' then - X(7 downto 0) <= ALU_Q; - end if; - if LDY = '1' then - Y(7 downto 0) <= ALU_Q; - end if; - if (LDA or LDX or LDY) = '1' then - P <= P_Out; - end if; - end if; - if SaveP = '1' then - P <= P_Out; - end if; - if LDP = '1' then - P <= ALU_Q; - end if; - if IR(4 downto 0) = "11000" then - case IR(7 downto 5) is - when "000" => - P(Flag_C) <= '0'; - when "001" => - P(Flag_C) <= '1'; - when "010" => - P(Flag_I) <= '0'; - when "011" => - P(Flag_I) <= '1'; - when "101" => - P(Flag_V) <= '0'; - when "110" => - P(Flag_D) <= '0'; - when "111" => - P(Flag_D) <= '1'; - when others => - end case; - end if; - - --if IR = "00000000" and MCycle = "011" and RstCycle = '0' and NMICycle = '0' and IRQCycle = '0' then - -- P(Flag_B) <= '1'; - --end if; - --if IR = "00000000" and MCycle = "100" and RstCycle = '0' and (NMICycle = '1' or IRQCycle = '1') then - -- P(Flag_I) <= '1'; - -- P(Flag_B) <= B_o; - --end if; - - -- B=1 always on the 6502 - P(Flag_B) <= '1'; - if IR = "00000000" and RstCycle = '0' and (NMICycle = '1' or IRQCycle = '1') then - if MCycle = "011" then - -- B=0 in *copy* of P pushed onto the stack - P(Flag_B) <= '0'; - elsif MCycle = "100" then - P(Flag_I) <= '1'; + if LDS = '1' then -- LAS won't work properly if not limited to machine cycle 0 + S(7 downto 0) <= unsigned(ALU_Q); + end if; end if; - end if; - if SO_n_o = '1' and SO_n = '0' then - P(Flag_V) <= '1'; - end if; - if RstCycle = '1' and Mode_r /= "00" then - P(Flag_1) <= '1'; - P(Flag_D) <= '0'; - P(Flag_I) <= '1'; - end if; - P(Flag_1) <= '1'; + ALU_Op_r <= ALU_Op; + Write_Data_r <= Write_Data; + if Break = '1' then + Set_Addr_To_r <= Set_Addr_To_PBR; + else + Set_Addr_To_r <= Set_Addr_To; + end if; - B_o <= P(Flag_B); - SO_n_o <= SO_n; - IRQ_n_o <= IRQ_n; - NMI_n_o <= NMI_n; - end if; - end if; - end if; - end process; + if Inc_S = '1' then + S <= S + 1; + end if; + if Dec_S = '1' and RstCycle = '0' then + S <= S - 1; + end if; + + if IR = "00000000" and MCycle = "001" and IRQCycle = '0' and NMICycle = '0' then + PC <= PC + 1; + end if; + -- + -- jump control logic + -- + case Jump is + when "01" => + PC <= PC + 1; + when "10" => + PC <= unsigned(DI & DL); + when "11" => + if PCAdder(8) = '1' then + if DL(7) = '0' then + PC(15 downto 8) <= PC(15 downto 8) + 1; + else + PC(15 downto 8) <= PC(15 downto 8) - 1; + end if; + end if; + PC(7 downto 0) <= PCAdder(7 downto 0); + when others => null; + end case; + end if; + end if; + end if; + end process; + + PCAdder <= resize(PC(7 downto 0),9) + resize(unsigned(DL(7) & DL),9) when PCAdd = '1' + else "0" & PC(7 downto 0); + + process (Res_n_i, Clk) + variable tmpP:std_logic_vector(7 downto 0);--Lets try to handle loading P at mcycle=0 and set/clk flags at same cycle + begin + if Res_n_i = '0' then + P <= x"00"; -- ensure we have nothing set on reset + elsif Clk'event and Clk = '1' then + tmpP:=P; + if (Enable = '1') then + if (really_rdy = '1') then + if MCycle = "000" then + if LDA = '1' then + ABC(7 downto 0) <= ALU_Q; + end if; + if LDX = '1' then + X(7 downto 0) <= ALU_Q; + end if; + if LDY = '1' then + Y(7 downto 0) <= ALU_Q; + end if; + if (LDA or LDX or LDY) = '1' then + tmpP:=P_Out; + end if; + end if; + if SaveP = '1' then + tmpP:=P_Out; + end if; + if LDP = '1' then + tmpP:=ALU_Q; + end if; + if IR(4 downto 0) = "11000" then + case IR(7 downto 5) is + when "000" =>--0x18(clc) + tmpP(Flag_C) := '0'; + when "001" =>--0x38(sec) + tmpP(Flag_C) := '1'; + when "010" =>--0x58(cli) + tmpP(Flag_I) := '0'; + when "011" =>--0x78(sei) + tmpP(Flag_I) := '1'; + when "101" =>--0xb8(clv) + tmpP(Flag_V) := '0'; + when "110" =>--0xd8(cld) + tmpP(Flag_D) := '0'; + when "111" =>--0xf8(sed) + tmpP(Flag_D) := '1'; + when others => + end case; + end if; + tmpP(Flag_B) := '1'; + if IR = "00000000" and MCycle = "100" and RstCycle = '0' then + --This should happen after P has been pushed to stack + tmpP(Flag_I) := '1'; + end if; + if SO_n_o = '1' and SO_n = '0' then + tmpP(Flag_V) := '1'; + end if; + if RstCycle = '1' then + tmpP(Flag_I) := '1'; + tmpP(Flag_D) := '0'; + end if; + tmpP(Flag_1) := '1'; + + P<=tmpP;--new way + + SO_n_o <= SO_n; + if IR(4 downto 0)/="10000" or Jump/="01" then -- delay interrupts during branches (checked with Lorenz test and real 6510), not best way yet, though - but works... + IRQ_n_o <= IRQ_n; + end if; + end if; + -- detect nmi even if not rdy + if IR(4 downto 0)/="10000" or Jump/="01" then -- delay interrupts during branches (checked with Lorenz test and real 6510) not best way yet, though - but works... + NMI_n_o <= NMI_n; + end if; + end if; + end if; + end process; --------------------------------------------------------------------------- -- @@ -415,109 +493,133 @@ begin -- --------------------------------------------------------------------------- - process (Res_n, Clk) - begin - if Res_n = '0' then - BusA_r <= (others => '0'); - BusB <= (others => '0'); - AD <= (others => '0'); - BAL <= (others => '0'); - BAH <= (others => '0'); - DL <= (others => '0'); - elsif Clk'event and Clk = '1' then - if (Enable = '1') then - if (Rdy = '1') then - BusA_r <= BusA; - BusB <= DI; + process (Res_n_i, Clk) + begin + if Res_n_i = '0' then + BusA_r <= (others => '0'); + BusB <= (others => '0'); + BusB_r <= (others => '0'); + AD <= (others => '0'); + BAL <= (others => '0'); + BAH <= (others => '0'); + DL <= (others => '0'); + elsif Clk'event and Clk = '1' then + if (Enable = '1') then + NMI_entered <= '0'; + if (really_rdy = '1') then + BusA_r <= BusA; + BusB <= DI; - case BAAdd is - when "01" => - -- BA Inc - AD <= std_logic_vector(unsigned(AD) + 1); - BAL <= std_logic_vector(unsigned(BAL) + 1); - when "10" => - -- BA Add - BAL <= std_logic_vector(resize(unsigned(BAL(7 downto 0)),9) + resize(unsigned(BusA),9)); - when "11" => - -- BA Adj - if BAL(8) = '1' then - BAH <= std_logic_vector(unsigned(BAH) + 1); - end if; - when others => - end case; + -- not really nice, but no better way found yet ! + if Set_Addr_To_r = Set_Addr_To_PBR or Set_Addr_To_r = Set_Addr_To_ZPG then + BusB_r <= std_logic_vector(unsigned(DI(7 downto 0)) + 1); -- required for SHA + end if; - -- ehenciak : modified to use Y register as well (bugfix) - if ADAdd = '1' then - if (AddY = '1') then - AD <= std_logic_vector(unsigned(AD) + unsigned(Y(7 downto 0))); - else - AD <= std_logic_vector(unsigned(AD) + unsigned(X(7 downto 0))); - end if; - end if; + case BAAdd is + when "01" => + -- BA Inc + AD <= std_logic_vector(unsigned(AD) + 1); + BAL <= std_logic_vector(unsigned(BAL) + 1); + when "10" => + -- BA Add + BAL <= std_logic_vector(resize(unsigned(BAL(7 downto 0)),9) + resize(unsigned(BusA),9)); + when "11" => + -- BA Adj + if BAL(8) = '1' then + BAH <= std_logic_vector(unsigned(BAH) + 1); + end if; + when others => + end case; - if IR = "00000000" then - BAL <= (others => '1'); - BAH <= (others => '1'); - if RstCycle = '1' then - BAL(2 downto 0) <= "100"; - elsif NMICycle = '1' then - BAL(2 downto 0) <= "010"; - else - BAL(2 downto 0) <= "110"; - end if; - if Set_addr_To_r = "11" then - BAL(0) <= '1'; - end if; - end if; + -- modified to use Y register as well + if ADAdd = '1' then + if (AddY = '1') then + AD <= std_logic_vector(unsigned(AD) + unsigned(Y(7 downto 0))); + else + AD <= std_logic_vector(unsigned(AD) + unsigned(X(7 downto 0))); + end if; + end if; + if IR = "00000000" then + BAL <= (others => '1'); + BAH <= (others => '1'); + if RstCycle = '1' then + BAL(2 downto 0) <= "100"; + elsif NMICycle = '1' or (NMIAct = '1' and MCycle="100") or NMI_entered='1' then + BAL(2 downto 0) <= "010"; + if MCycle="100" then + NMI_entered <= '1'; + end if; + else + BAL(2 downto 0) <= "110"; + end if; + if Set_addr_To_r = Set_Addr_To_BA then + BAL(0) <= '1'; + end if; + end if; - if LDDI = '1' then - DL <= DI; - end if; - if LDALU = '1' then - DL <= ALU_Q; - end if; - if LDAD = '1' then - AD <= DI; - end if; - if LDBAL = '1' then - BAL(7 downto 0) <= DI; - end if; - if LDBAH = '1' then - BAH <= DI; - end if; - end if; - end if; - end if; - end process; + if LDDI = '1' then + DL <= DI; + end if; + if LDALU = '1' then + DL <= ALU_Q; + end if; + if LDAD = '1' then + AD <= DI; + end if; + if LDBAL = '1' then + BAL(7 downto 0) <= DI; + end if; + if LDBAH = '1' then + BAH <= DI; + end if; + end if; + end if; + end if; + end process; - Break <= (BreakAtNA and not BAL(8)) or (PCAdd and not PCAdder(8)); + Break <= (BreakAtNA and not BAL(8)) or (PCAdd and not PCAdder(8)); + with Set_BusA_To select + BusA <= + DI when Set_BusA_To_DI, + ABC(7 downto 0) when Set_BusA_To_ABC, + X(7 downto 0) when Set_BusA_To_X, + Y(7 downto 0) when Set_BusA_To_Y, + std_logic_vector(S(7 downto 0)) when Set_BusA_To_S, + P when Set_BusA_To_P, + ABC(7 downto 0) and DI when Set_BusA_To_DA, + (ABC(7 downto 0) or x"ee") and DI when Set_BusA_To_DAO,--ee for OAL instruction. constant may be different on other platforms.TODO:Move to generics + (ABC(7 downto 0) or x"ee") and DI and X(7 downto 0) when Set_BusA_To_DAX,--XAA, ee for OAL instruction. constant may be different on other platforms.TODO:Move to generics + ABC(7 downto 0) and X(7 downto 0) when Set_BusA_To_AAX,--SAX, SHA + (others => '-') when Set_BusA_To_DONTCARE;--Can probably remove this - with Set_BusA_To select - BusA <= DI when "000", - ABC(7 downto 0) when "001", - X(7 downto 0) when "010", - Y(7 downto 0) when "011", - std_logic_vector(S(7 downto 0)) when "100", - P when "101", - (others => '-') when others; + with Set_Addr_To_r select + A <= + "0000000000000001" & std_logic_vector(S(7 downto 0)) when Set_Addr_To_SP, + DBR & "00000000" & AD when Set_Addr_To_ZPG, + "00000000" & BAH & BAL(7 downto 0) when Set_Addr_To_BA, + PBR & std_logic_vector(PC(15 downto 8)) & std_logic_vector(PCAdder(7 downto 0)) when Set_Addr_To_PBR; - with Set_Addr_To_r select - A <= "0000000000000001" & std_logic_vector(S(7 downto 0)) when "01", - DBR & "00000000" & AD when "10", - "00000000" & BAH & BAL(7 downto 0) when "11", - PBR & std_logic_vector(PC(15 downto 8)) & std_logic_vector(PCAdder(7 downto 0)) when others; + -- This is the P that gets pushed on stack with correct B flag. I'm not sure if NMI also clears B, but I guess it does. + PwithB<=(P and x"ef") when (IRQCycle='1' or NMICycle='1') else P; + + with Write_Data_r select + DO <= + DL when Write_Data_DL, + ABC(7 downto 0) when Write_Data_ABC, + X(7 downto 0) when Write_Data_X, + Y(7 downto 0) when Write_Data_Y, + std_logic_vector(S(7 downto 0)) when Write_Data_S, + PwithB when Write_Data_P, + std_logic_vector(PC(7 downto 0)) when Write_Data_PCL, + std_logic_vector(PC(15 downto 8)) when Write_Data_PCH, + ABC(7 downto 0) and X(7 downto 0) when Write_Data_AX, + ABC(7 downto 0) and X(7 downto 0) and BusB_r(7 downto 0) when Write_Data_AXB, -- no better way found yet... + X(7 downto 0) and BusB_r(7 downto 0) when Write_Data_XB, -- no better way found yet... + Y(7 downto 0) and BusB_r(7 downto 0) when Write_Data_YB, -- no better way found yet... + (others=>'-') when Write_Data_DONTCARE;--Can probably remove this - with Write_Data_r select - DO <= DL when "000", - ABC(7 downto 0) when "001", - X(7 downto 0) when "010", - Y(7 downto 0) when "011", - std_logic_vector(S(7 downto 0)) when "100", - P when "101", - std_logic_vector(PC(7 downto 0)) when "110", - std_logic_vector(PC(15 downto 8)) when others; ------------------------------------------------------------------------- -- @@ -525,40 +627,42 @@ begin -- ------------------------------------------------------------------------- - process (Res_n, Clk) - begin - if Res_n = '0' then - MCycle <= "001"; - RstCycle <= '1'; - IRQCycle <= '0'; - NMICycle <= '0'; - NMIAct <= '0'; - elsif Clk'event and Clk = '1' then - if (Enable = '1') then - if (really_rdy = '1') then - if MCycle = LCycle or Break = '1' then - MCycle <= "000"; - RstCycle <= '0'; - IRQCycle <= '0'; - NMICycle <= '0'; - if NMIAct = '1' then - NMICycle <= '1'; - elsif IRQ_n_o = '0' and P(Flag_I) = '0' then - IRQCycle <= '1'; - end if; - else - MCycle <= std_logic_vector(unsigned(MCycle) + 1); - end if; - - if NMICycle = '1' then - NMIAct <= '0'; - end if; - if NMI_n_o = '1' and NMI_n = '0' then - NMIAct <= '1'; - end if; - end if; - end if; - end if; - end process; + process (Res_n_i, Clk) + begin + if Res_n_i = '0' then + MCycle <= "001"; + RstCycle <= '1'; + IRQCycle <= '0'; + NMICycle <= '0'; + NMIAct <= '0'; + elsif Clk'event and Clk = '1' then + if (Enable = '1') then + if (really_rdy = '1') then + if MCycle = LCycle or Break = '1' then + MCycle <= "000"; + RstCycle <= '0'; + IRQCycle <= '0'; + NMICycle <= '0'; + if NMIAct = '1' and IR/=x"00" then -- delay NMI further if we just executed a BRK + NMICycle <= '1'; + NMIAct <= '0'; -- reset NMI edge detector if we start processing the NMI + elsif IRQ_n_o = '0' and P(Flag_I) = '0' then + IRQCycle <= '1'; + end if; + else + MCycle <= std_logic_vector(unsigned(MCycle) + 1); + end if; + end if; + --detect NMI even if not rdy + if NMI_n_o = '1' and (NMI_n = '0' and (IR(4 downto 0)/="10000" or Jump/="01")) then -- branches have influence on NMI start (not best way yet, though - but works...) + NMIAct <= '1'; + end if; + -- we entered NMI during BRK instruction + if NMI_entered='1' then + NMIAct <= '0'; + end if; + end if; + end if; + end process; end; diff --git a/cores/c16/t65/T65_ALU.vhd b/cores/c16/t65/T65_ALU.vhd old mode 100644 new mode 100755 index d9d25e1..c076ab0 --- a/cores/c16/t65/T65_ALU.vhd +++ b/cores/c16/t65/T65_ALU.vhd @@ -1,18 +1,18 @@ -- **** -- T65(b) core. In an effort to merge and maintain bug fixes .... -- --- --- Ver 300 Bugfixes by ehenciak added --- MikeJ March 2005 --- Latest version from www.fpgaarcade.com (original www.opencores.org) +-- See list of changes in T65 top file (T65.vhd)... -- -- **** +-- 65xx compatible microprocessor core -- --- 6502 compatible microprocessor core +-- FPGAARCADE SVN: $Id: T65_ALU.vhd 1234 2015-02-28 20:14:50Z wolfgang.scherr $ -- --- Version : 0245 --- --- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org) +-- Copyright (c) 2002...2015 +-- Daniel Wallner (jesus opencores org) +-- Mike Johnson (mikej fpgaarcade com) +-- Wolfgang Scherr (WoS pin4 at> +-- Morten Leikvoll () -- -- All rights reserved -- @@ -42,19 +42,12 @@ -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- --- Please report bugs to the author, but before you do so, please +-- Please report bugs to the author(s), but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- --- The latest version of this file can be found at: --- http://www.opencores.org/cvsweb.shtml/t65/ --- -- Limitations : --- --- File history : --- --- 0245 : First version --- +-- See in T65 top file (T65.vhd)... library IEEE; use IEEE.std_logic_1164.all; @@ -62,199 +55,239 @@ use IEEE.numeric_std.all; use work.T65_Pack.all; entity T65_ALU is - port( - Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816 - Op : in std_logic_vector(3 downto 0); - BusA : in std_logic_vector(7 downto 0); - BusB : in std_logic_vector(7 downto 0); - P_In : in std_logic_vector(7 downto 0); - P_Out : out std_logic_vector(7 downto 0); - Q : out std_logic_vector(7 downto 0) - ); + port( + Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816 + Op : in T_ALU_OP; + BusA : in std_logic_vector(7 downto 0); + BusB : in std_logic_vector(7 downto 0); + P_In : in std_logic_vector(7 downto 0); + P_Out : out std_logic_vector(7 downto 0); + Q : out std_logic_vector(7 downto 0) + ); end T65_ALU; architecture rtl of T65_ALU is - -- AddSub variables (temporary signals) - signal ADC_Z : std_logic; - signal ADC_C : std_logic; - signal ADC_V : std_logic; - signal ADC_N : std_logic; - signal ADC_Q : std_logic_vector(7 downto 0); - signal SBC_Z : std_logic; - signal SBC_C : std_logic; - signal SBC_V : std_logic; - signal SBC_N : std_logic; - signal SBC_Q : std_logic_vector(7 downto 0); + -- AddSub variables (temporary signals) + signal ADC_Z : std_logic; + signal ADC_C : std_logic; + signal ADC_V : std_logic; + signal ADC_N : std_logic; + signal ADC_Q : std_logic_vector(7 downto 0); + signal SBC_Z : std_logic; + signal SBC_C : std_logic; + signal SBC_V : std_logic; + signal SBC_N : std_logic; + signal SBC_Q : std_logic_vector(7 downto 0); + signal SBX_Q : std_logic_vector(7 downto 0); begin - process (P_In, BusA, BusB) - variable AL : unsigned(6 downto 0); - variable AH : unsigned(6 downto 0); - variable C : std_logic; - begin - AL := resize(unsigned(BusA(3 downto 0) & P_In(Flag_C)), 7) + resize(unsigned(BusB(3 downto 0) & "1"), 7); - AH := resize(unsigned(BusA(7 downto 4) & AL(5)), 7) + resize(unsigned(BusB(7 downto 4) & "1"), 7); + process (P_In, BusA, BusB) + variable AL : unsigned(6 downto 0); + variable AH : unsigned(6 downto 0); + variable C : std_logic; + begin + AL := resize(unsigned(BusA(3 downto 0) & P_In(Flag_C)), 7) + resize(unsigned(BusB(3 downto 0) & "1"), 7); + AH := resize(unsigned(BusA(7 downto 4) & AL(5)), 7) + resize(unsigned(BusB(7 downto 4) & "1"), 7); -- pragma translate_off - if is_x(std_logic_vector(AL)) then AL := "0000000"; end if; - if is_x(std_logic_vector(AH)) then AH := "0000000"; end if; + if is_x(std_logic_vector(AL)) then AL := "0000000"; end if; + if is_x(std_logic_vector(AH)) then AH := "0000000"; end if; -- pragma translate_on - if AL(4 downto 1) = 0 and AH(4 downto 1) = 0 then - ADC_Z <= '1'; - else - ADC_Z <= '0'; - end if; + if AL(4 downto 1) = 0 and AH(4 downto 1) = 0 then + ADC_Z <= '1'; + else + ADC_Z <= '0'; + end if; - if AL(5 downto 1) > 9 and P_In(Flag_D) = '1' then - AL(6 downto 1) := AL(6 downto 1) + 6; - end if; + if AL(5 downto 1) > 9 and P_In(Flag_D) = '1' then + AL(6 downto 1) := AL(6 downto 1) + 6; + end if; - C := AL(6) or AL(5); - AH := resize(unsigned(BusA(7 downto 4) & C), 7) + resize(unsigned(BusB(7 downto 4) & "1"), 7); + C := AL(6) or AL(5); + AH := resize(unsigned(BusA(7 downto 4) & C), 7) + resize(unsigned(BusB(7 downto 4) & "1"), 7); - ADC_N <= AH(4); - ADC_V <= (AH(4) xor BusA(7)) and not (BusA(7) xor BusB(7)); + ADC_N <= AH(4); + ADC_V <= (AH(4) xor BusA(7)) and not (BusA(7) xor BusB(7)); -- pragma translate_off - if is_x(std_logic_vector(AH)) then AH := "0000000"; end if; + if is_x(std_logic_vector(AH)) then AH := "0000000"; end if; -- pragma translate_on - if AH(5 downto 1) > 9 and P_In(Flag_D) = '1' then - AH(6 downto 1) := AH(6 downto 1) + 6; - end if; + if AH(5 downto 1) > 9 and P_In(Flag_D) = '1' then + AH(6 downto 1) := AH(6 downto 1) + 6; + end if; - ADC_C <= AH(6) or AH(5); + ADC_C <= AH(6) or AH(5); - ADC_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1)); - end process; + ADC_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1)); + end process; - process (Op, P_In, BusA, BusB) - variable AL : unsigned(6 downto 0); - variable AH : unsigned(5 downto 0); - variable C : std_logic; - begin - C := P_In(Flag_C) or not Op(0); - AL := resize(unsigned(BusA(3 downto 0) & C), 7) - resize(unsigned(BusB(3 downto 0) & "1"), 6); - AH := resize(unsigned(BusA(7 downto 4) & "0"), 6) - resize(unsigned(BusB(7 downto 4) & AL(5)), 6); + process (Op, P_In, BusA, BusB) + variable AL : unsigned(6 downto 0); + variable AH : unsigned(5 downto 0); + variable C : std_logic; + variable CT : std_logic; + begin + CT:='0'; + if( Op=ALU_OP_AND or --"0001" These OpCodes used to have LSB set + Op=ALU_OP_ADC or --"0011" + Op=ALU_OP_EQ2 or --"0101" + Op=ALU_OP_SBC or --"0111" + Op=ALU_OP_ROL or --"1001" + Op=ALU_OP_ROR or --"1011" +-- Op=ALU_OP_EQ3 or --"1101" + Op=ALU_OP_INC --"1111" + ) then + CT:='1'; + end if; --- pragma translate_off - if is_x(std_logic_vector(AL)) then AL := "0000000"; end if; - if is_x(std_logic_vector(AH)) then AH := "000000"; end if; --- pragma translate_on + C := P_In(Flag_C) or not CT;--was: or not Op(0); + AL := resize(unsigned(BusA(3 downto 0) & C), 7) - resize(unsigned(BusB(3 downto 0) & "1"), 6); + AH := resize(unsigned(BusA(7 downto 4) & "0"), 6) - resize(unsigned(BusB(7 downto 4) & AL(5)), 6); - if AL(4 downto 1) = 0 and AH(4 downto 1) = 0 then - SBC_Z <= '1'; - else - SBC_Z <= '0'; - end if; + -- pragma translate_off + if is_x(std_logic_vector(AL)) then AL := "0000000"; end if; + if is_x(std_logic_vector(AH)) then AH := "000000"; end if; + -- pragma translate_on - SBC_C <= not AH(5); - SBC_V <= (AH(4) xor BusA(7)) and (BusA(7) xor BusB(7)); - SBC_N <= AH(4); + if AL(4 downto 1) = 0 and AH(4 downto 1) = 0 then + SBC_Z <= '1'; + else + SBC_Z <= '0'; + end if; - if P_In(Flag_D) = '1' then - if AL(5) = '1' then - AL(5 downto 1) := AL(5 downto 1) - 6; - end if; - AH := resize(unsigned(BusA(7 downto 4) & "0"), 6) - resize(unsigned(BusB(7 downto 4) & AL(6)), 6); - if AH(5) = '1' then - AH(5 downto 1) := AH(5 downto 1) - 6; - end if; - end if; + SBC_C <= not AH(5); + SBC_V <= (AH(4) xor BusA(7)) and (BusA(7) xor BusB(7)); + SBC_N <= AH(4); - SBC_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1)); - end process; + SBX_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1)); - process (Op, P_In, BusA, BusB, - ADC_Z, ADC_C, ADC_V, ADC_N, ADC_Q, - SBC_Z, SBC_C, SBC_V, SBC_N, SBC_Q) - variable Q_t : std_logic_vector(7 downto 0); - begin - -- ORA, AND, EOR, ADC, NOP, LD, CMP, SBC - -- ASL, ROL, LSR, ROR, BIT, LD, DEC, INC - P_Out <= P_In; - Q_t := BusA; - case Op(3 downto 0) is - when "0000" => - -- ORA - Q_t := BusA or BusB; - when "0001" => - -- AND - Q_t := BusA and BusB; - when "0010" => - -- EOR - Q_t := BusA xor BusB; - when "0011" => - -- ADC - P_Out(Flag_V) <= ADC_V; - P_Out(Flag_C) <= ADC_C; - Q_t := ADC_Q; - when "0101" | "1101" => - -- LDA - when "0110" => - -- CMP - P_Out(Flag_C) <= SBC_C; - when "0111" => - -- SBC - P_Out(Flag_V) <= SBC_V; - P_Out(Flag_C) <= SBC_C; - Q_t := SBC_Q; - when "1000" => - -- ASL - Q_t := BusA(6 downto 0) & "0"; - P_Out(Flag_C) <= BusA(7); - when "1001" => - -- ROL - Q_t := BusA(6 downto 0) & P_In(Flag_C); - P_Out(Flag_C) <= BusA(7); - when "1010" => - -- LSR - Q_t := "0" & BusA(7 downto 1); - P_Out(Flag_C) <= BusA(0); - when "1011" => - -- ROR - Q_t := P_In(Flag_C) & BusA(7 downto 1); - P_Out(Flag_C) <= BusA(0); - when "1100" => - -- BIT - P_Out(Flag_V) <= BusB(6); - when "1110" => - -- DEC - Q_t := std_logic_vector(unsigned(BusA) - 1); - when "1111" => - -- INC - Q_t := std_logic_vector(unsigned(BusA) + 1); - when others => - end case; + if P_In(Flag_D) = '1' then + if AL(5) = '1' then + AL(5 downto 1) := AL(5 downto 1) - 6; + end if; + AH := resize(unsigned(BusA(7 downto 4) & "0"), 6) - resize(unsigned(BusB(7 downto 4) & AL(6)), 6); + if AH(5) = '1' then + AH(5 downto 1) := AH(5 downto 1) - 6; + end if; + end if; - case Op(3 downto 0) is - when "0011" => - P_Out(Flag_N) <= ADC_N; - P_Out(Flag_Z) <= ADC_Z; - when "0110" | "0111" => - P_Out(Flag_N) <= SBC_N; - P_Out(Flag_Z) <= SBC_Z; - when "0100" => - when "1100" => - P_Out(Flag_N) <= BusB(7); - if (BusA and BusB) = "00000000" then - P_Out(Flag_Z) <= '1'; - else - P_Out(Flag_Z) <= '0'; - end if; - when others => - P_Out(Flag_N) <= Q_t(7); - if Q_t = "00000000" then - P_Out(Flag_Z) <= '1'; - else - P_Out(Flag_Z) <= '0'; - end if; - end case; + SBC_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1)); + end process; - Q <= Q_t; - end process; + process (Op, P_In, BusA, BusB, + ADC_Z, ADC_C, ADC_V, ADC_N, ADC_Q, + SBC_Z, SBC_C, SBC_V, SBC_N, SBC_Q, + SBX_Q) + variable Q_t : std_logic_vector(7 downto 0); + variable Q2_t : std_logic_vector(7 downto 0); + begin + -- ORA, AND, EOR, ADC, NOP, LD, CMP, SBC + -- ASL, ROL, LSR, ROR, BIT, LD, DEC, INC + P_Out <= P_In; + Q_t := BusA; + Q2_t := BusA; + case Op is + when ALU_OP_OR=> + Q_t := BusA or BusB; + when ALU_OP_AND=> + Q_t := BusA and BusB; + when ALU_OP_EOR=> + Q_t := BusA xor BusB; + when ALU_OP_ADC=> + P_Out(Flag_V) <= ADC_V; + P_Out(Flag_C) <= ADC_C; + Q_t := ADC_Q; + when ALU_OP_CMP=> + P_Out(Flag_C) <= SBC_C; + when ALU_OP_SAX=> + P_Out(Flag_C) <= SBC_C; + Q_t := SBX_Q; -- undoc: subtract (A & X) - (immediate) + when ALU_OP_SBC=> + P_Out(Flag_V) <= SBC_V; + P_Out(Flag_C) <= SBC_C; + Q_t := SBC_Q; -- undoc: subtract (A & X) - (immediate), then decimal correction + when ALU_OP_ASL=> + Q_t := BusA(6 downto 0) & "0"; + P_Out(Flag_C) <= BusA(7); + when ALU_OP_ROL=> + Q_t := BusA(6 downto 0) & P_In(Flag_C); + P_Out(Flag_C) <= BusA(7); + when ALU_OP_LSR=> + Q_t := "0" & BusA(7 downto 1); + P_Out(Flag_C) <= BusA(0); + when ALU_OP_ROR=> + Q_t := P_In(Flag_C) & BusA(7 downto 1); + P_Out(Flag_C) <= BusA(0); + when ALU_OP_ARR=> + Q_t := P_In(Flag_C) & (BusA(7 downto 1) and BusB(7 downto 1)); + P_Out(Flag_V) <= Q_t(5) xor Q_t(6); + Q2_t := Q_t; + if P_In(Flag_D)='1' then + if (BusA(3 downto 0) and BusB(3 downto 0)) > "0100" then + Q2_t(3 downto 0) := std_logic_vector(unsigned(Q_t(3 downto 0)) + x"6"); + end if; + if (BusA(7 downto 4) and BusB(7 downto 4)) > "0100" then + Q2_t(7 downto 4) := std_logic_vector(unsigned(Q_t(7 downto 4)) + x"6"); + P_Out(Flag_C) <= '1'; + else + P_Out(Flag_C) <= '0'; + end if; + else + P_Out(Flag_C) <= Q_t(6); + end if; + when ALU_OP_BIT=> + P_Out(Flag_V) <= BusB(6); + when ALU_OP_DEC=> + Q_t := std_logic_vector(unsigned(BusA) - 1); + when ALU_OP_INC=> + Q_t := std_logic_vector(unsigned(BusA) + 1); + when others => + null; + --EQ1,EQ2,EQ3 passes BusA to Q_t and P_in to P_out + end case; + + case Op is + when ALU_OP_ADC=> + P_Out(Flag_N) <= ADC_N; + P_Out(Flag_Z) <= ADC_Z; + when ALU_OP_CMP|ALU_OP_SBC|ALU_OP_SAX=> + P_Out(Flag_N) <= SBC_N; + P_Out(Flag_Z) <= SBC_Z; + when ALU_OP_EQ1=>--dont touch P + when ALU_OP_BIT=> + P_Out(Flag_N) <= BusB(7); + if (BusA and BusB) = "00000000" then + P_Out(Flag_Z) <= '1'; + else + P_Out(Flag_Z) <= '0'; + end if; + when ALU_OP_ANC=> + P_Out(Flag_N) <= Q_t(7); + P_Out(Flag_C) <= Q_t(7); + if Q_t = "00000000" then + P_Out(Flag_Z) <= '1'; + else + P_Out(Flag_Z) <= '0'; + end if; + when others => + P_Out(Flag_N) <= Q_t(7); + if Q_t = "00000000" then + P_Out(Flag_Z) <= '1'; + else + P_Out(Flag_Z) <= '0'; + end if; + end case; + + if Op=ALU_OP_ARR then + -- handled above in ARR code + Q <= Q2_t; + else + Q <= Q_t; + end if; + end process; end; diff --git a/cores/c16/t65/T65_MCode.vhd b/cores/c16/t65/T65_MCode.vhd old mode 100644 new mode 100755 index 3fd40d8..867e0b8 --- a/cores/c16/t65/T65_MCode.vhd +++ b/cores/c16/t65/T65_MCode.vhd @@ -1,20 +1,18 @@ -- **** -- T65(b) core. In an effort to merge and maintain bug fixes .... -- --- --- Ver 302 minor timing fixes --- Ver 301 Jump timing fixed --- Ver 300 Bugfixes by ehenciak added --- MikeJ March 2005 --- Latest version from www.fpgaarcade.com (original www.opencores.org) +-- See list of changes in T65 top file (T65.vhd)... -- -- **** --- -- 65xx compatible microprocessor core -- --- Version : 0246 + fix +-- FPGAARCADE SVN: $Id: T65_MCode.vhd 1234 2015-02-28 20:14:50Z wolfgang.scherr $ -- --- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org) +-- Copyright (c) 2002...2015 +-- Daniel Wallner (jesus opencores org) +-- Mike Johnson (mikej fpgaarcade com) +-- Wolfgang Scherr (WoS pin4 at> +-- Morten Leikvoll () -- -- All rights reserved -- @@ -44,1009 +42,1198 @@ -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- --- Please report bugs to the author, but before you do so, please +-- Please report bugs to the author(s), but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- --- The latest version of this file can be found at: --- http://www.opencores.org/cvsweb.shtml/t65/ --- -- Limitations : --- --- 65C02 --- supported : inc, dec, phx, plx, phy, ply --- missing : bra, ora, lda, cmp, sbc, tsb*2, trb*2, stz*2, bit*2, wai, stp, jmp, bbr*8, bbs*8 --- --- File history : --- --- 0246 : First release --- +-- See in T65 top file (T65.vhd)... library IEEE; use IEEE.std_logic_1164.all; use IEEE.numeric_std.all; +use ieee.std_logic_unsigned.all; use work.T65_Pack.all; entity T65_MCode is - port( - Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816 - IR : in std_logic_vector(7 downto 0); - MCycle : in std_logic_vector(2 downto 0); - P : in std_logic_vector(7 downto 0); - LCycle : out std_logic_vector(2 downto 0); - ALU_Op : out std_logic_vector(3 downto 0); - Set_BusA_To : out std_logic_vector(2 downto 0); -- DI,A,X,Y,S,P - Set_Addr_To : out std_logic_vector(1 downto 0); -- PC Adder,S,AD,BA - Write_Data : out std_logic_vector(2 downto 0); -- DL,A,X,Y,S,P,PCL,PCH - Jump : out std_logic_vector(1 downto 0); -- PC,++,DIDL,Rel - BAAdd : out std_logic_vector(1 downto 0); -- None,DB Inc,BA Add,BA Adj - BreakAtNA : out std_logic; - ADAdd : out std_logic; - AddY : out std_logic; - PCAdd : out std_logic; - Inc_S : out std_logic; - Dec_S : out std_logic; - LDA : out std_logic; - LDP : out std_logic; - LDX : out std_logic; - LDY : out std_logic; - LDS : out std_logic; - LDDI : out std_logic; - LDALU : out std_logic; - LDAD : out std_logic; - LDBAL : out std_logic; - LDBAH : out std_logic; - SaveP : out std_logic; - Write : out std_logic - ); + port( + Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816 + IR : in std_logic_vector(7 downto 0); + MCycle : in T_Lcycle; + P : in std_logic_vector(7 downto 0); + LCycle : out T_Lcycle; + ALU_Op : out T_ALU_Op; + Set_BusA_To : out T_Set_BusA_To; -- DI,A,X,Y,S,P,DA,DAO,DAX,AAX + Set_Addr_To : out T_Set_Addr_To; -- PC Adder,S,AD,BA + Write_Data : out T_Write_Data; -- DL,A,X,Y,S,P,PCL,PCH,AX,AXB,XB,YB + Jump : out std_logic_vector(1 downto 0); -- PC,++,DIDL,Rel + BAAdd : out std_logic_vector(1 downto 0); -- None,DB Inc,BA Add,BA Adj + BreakAtNA : out std_logic; + ADAdd : out std_logic; + AddY : out std_logic; + PCAdd : out std_logic; + Inc_S : out std_logic; + Dec_S : out std_logic; + LDA : out std_logic; + LDP : out std_logic; + LDX : out std_logic; + LDY : out std_logic; + LDS : out std_logic; + LDDI : out std_logic; + LDALU : out std_logic; + LDAD : out std_logic; + LDBAL : out std_logic; + LDBAH : out std_logic; + SaveP : out std_logic; + Write : out std_logic + ); end T65_MCode; architecture rtl of T65_MCode is - signal Branch : std_logic; + signal Branch : std_logic; + signal ALUmore:std_logic; begin - with IR(7 downto 5) select - Branch <= not P(Flag_N) when "000", - P(Flag_N) when "001", - not P(Flag_V) when "010", - P(Flag_V) when "011", - not P(Flag_C) when "100", - P(Flag_C) when "101", - not P(Flag_Z) when "110", - P(Flag_Z) when others; + with IR(7 downto 5) select + Branch <= not P(Flag_N) when "000", + P(Flag_N) when "001", + not P(Flag_V) when "010", + P(Flag_V) when "011", + not P(Flag_C) when "100", + P(Flag_C) when "101", + not P(Flag_Z) when "110", + P(Flag_Z) when others; - process (IR, MCycle, P, Branch, Mode) - begin - LCycle <= "001"; - Set_BusA_To <= "001"; -- A - Set_Addr_To <= (others => '0'); - Write_Data <= (others => '0'); - Jump <= (others => '0'); - BAAdd <= "00"; - BreakAtNA <= '0'; - ADAdd <= '0'; - PCAdd <= '0'; - Inc_S <= '0'; - Dec_S <= '0'; - LDA <= '0'; - LDP <= '0'; - LDX <= '0'; - LDY <= '0'; - LDS <= '0'; - LDDI <= '0'; - LDALU <= '0'; - LDAD <= '0'; - LDBAL <= '0'; - LDBAH <= '0'; - SaveP <= '0'; - Write <= '0'; - AddY <= '0'; + process (IR, MCycle, P, Branch, Mode) + begin + lCycle <= Cycle_1; + Set_BusA_To <= Set_BusA_To_ABC; + Set_Addr_To <= Set_Addr_To_PBR; + Write_Data <= Write_Data_DL; + Jump <= (others => '0'); + BAAdd <= "00"; + BreakAtNA <= '0'; + ADAdd <= '0'; + PCAdd <= '0'; + Inc_S <= '0'; + Dec_S <= '0'; + LDA <= '0'; + LDP <= '0'; + LDX <= '0'; + LDY <= '0'; + LDS <= '0'; + LDDI <= '0'; + LDALU <= '0'; + LDAD <= '0'; + LDBAL <= '0'; + LDBAH <= '0'; + SaveP <= '0'; + Write <= '0'; + AddY <= '0'; + ALUmore <= '0'; - case IR(7 downto 5) is - when "100" => - --{{{ - case IR(1 downto 0) is - when "00" => - Set_BusA_To <= "011"; -- Y - Write_Data <= "011"; -- Y - when "10" => - Set_BusA_To <= "010"; -- X - Write_Data <= "010"; -- X - when others => - Write_Data <= "001"; -- A - end case; - --}}} - when "101" => - --{{{ - case IR(1 downto 0) is - when "00" => - if IR(4) /= '1' or IR(2) /= '0' then - LDY <= '1'; - end if; - when "10" => - LDX <= '1'; - when others => - LDA <= '1'; - end case; - Set_BusA_To <= "000"; -- DI - --}}} - when "110" => - --{{{ - case IR(1 downto 0) is - when "00" => - if IR(4) = '0' then - LDY <= '1'; - end if; - Set_BusA_To <= "011"; -- Y - when others => - Set_BusA_To <= "001"; -- A - end case; - --}}} - when "111" => - --{{{ - case IR(1 downto 0) is - when "00" => - if IR(4) = '0' then - LDX <= '1'; - end if; - Set_BusA_To <= "010"; -- X - when others => - Set_BusA_To <= "001"; -- A - end case; - --}}} - when others => - end case; + case IR(7 downto 5) is + when "100" => -- covers $8x,$9x + case IR(1 downto 0) is + when "00" => -- IR: $80,$84,$88,$8C,$90,$94,$98,$9C + Set_BusA_To <= Set_BusA_To_Y; + if IR(4 downto 2)="111" then -- SYA ($9C) + Write_Data <= Write_Data_YB; + else + Write_Data <= Write_Data_Y; + end if; + when "10" => -- IR: $82,$86,$8A,$8E,$92,$96,$9A,$9E + Set_BusA_To <= Set_BusA_To_X; + if IR(4 downto 2)="111" then -- SXA ($9E) + Write_Data <= Write_Data_XB; + else + Write_Data <= Write_Data_X; + end if; + when "11" => -- IR: $83,$87,$8B,$8F,$93,$97,$9B,$9F + if IR(4 downto 2)="110" then -- SHS ($9B) + Set_BusA_To <= Set_BusA_To_AAX; + LDS <= '1'; + else + Set_BusA_To <= Set_BusA_To_ABC; + end if; + if IR(4 downto 2)="111" or IR(4 downto 2)="110" or IR(4 downto 2)="100" then -- SHA ($9F, $93), SHS ($9B) + Write_Data <= Write_Data_AXB; + else + Write_Data <= Write_Data_AX; + end if; + when others => -- IR: $81,$85,$89,$8D,$91,$95,$99,$9D + Write_Data <= Write_Data_ABC; + end case; + when "101" => -- covers $Ax,$Bx + Set_BusA_To <= Set_BusA_To_DI; + case IR(1 downto 0) is + when "00" => -- IR: $A0,$A4,$A8,$AC,$B0,$B4,$B8,$BC + if IR(4) /= '1' or IR(2) /= '0' then--only for $A0,$A4,$A8,$AC or $B4,$BC + LDY <= '1'; + end if; + when "01" => -- IR: $A1,$A5,$A9,$AD,$B1,$B5,$B9,$BD + LDA <= '1'; + when "10" => -- IR: $A2,$A6,$AA,$AE,$B2,$B6,$BA,$BE + LDX <= '1'; + when others => -- IR: $A3,$A7,$AB,$AF,$B3,$B7,$BB,$BF (undoc) + LDX <= '1'; + LDA <= '1'; + if IR(4 downto 2)="110" then -- LAS (BB) + Set_BusA_To <= Set_BusA_To_S; + LDS <= '1'; + end if; + end case; + when "110" => -- covers $Cx,$Dx + case IR(1 downto 0) is + when "00" => -- IR: $C0,$C4,$C8,$CC,$D0,$D4,$D8,$DC + if IR(4) = '0' then--only for $Cx + LDY <= '1'; + end if; + Set_BusA_To <= Set_BusA_To_Y; + when others => -- IR: $C1,$C5,$C9,$CD,$D1,$D5,$D9,$DD, $C2,$C6,$CA,$CE,$D2,$D6,$DA,$DE, $C3,$C7,$CB,$CF,$D3,$D7,$DB,$DF + Set_BusA_To <= Set_BusA_To_ABC; + end case; + when "111" => -- covers $Ex,$Fx + case IR(1 downto 0) is + when "00" => -- IR: $E0,$E4,$E8,$EC,$F0,$F4,$F8,$FC + if IR(4) = '0' then -- only $Ex + LDX <= '1'; + end if; + Set_BusA_To <= Set_BusA_To_X; + when others => -- IR: $E1,$E5,$E9,$ED,$F1,$F5,$F9,$FD, $E2,$E6,$EA,$EE,$F2,$F6,$FA,$FE, $E3,$E7,$EB,$EF,$F3,$F7,$FB,$FF + Set_BusA_To <= Set_BusA_To_ABC; + end case; + when others => + end case; - if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then - Set_BusA_To <= "000"; -- DI - end if; + if IR(7 downto 6) /= "10" and IR(1) = '1' and (mode="00" or IR(0)='0') then--covers $0x-$7x, $Cx-$Fx x=2,3,6,7,A,B,E,F, for 6502 undocs + if IR=x"eb" then + Set_BusA_To <= Set_BusA_To_ABC; -- alternate SBC ($EB) + else + Set_BusA_To <= Set_BusA_To_DI; + end if; + end if; - case IR(4 downto 0) is - when "00000" | "01000" | "01010" | "11000" | "11010" => - --{{{ - -- Implied - case IR is - when "00000000" => - -- BRK - LCycle <= "110"; - case to_integer(unsigned(MCycle)) is - when 1 => - Set_Addr_To <= "01"; -- S - Write_Data <= "111"; -- PCH - Write <= '1'; - when 2 => - Dec_S <= '1'; - Set_Addr_To <= "01"; -- S - Write_Data <= "110"; -- PCL - Write <= '1'; - when 3 => - Dec_S <= '1'; - Set_Addr_To <= "01"; -- S - Write_Data <= "101"; -- P - Write <= '1'; - when 4 => - Dec_S <= '1'; - Set_Addr_To <= "11"; -- BA - when 5 => - LDDI <= '1'; - Set_Addr_To <= "11"; -- BA - when 6 => - Jump <= "10"; -- DIDL - when others => - end case; - when "00100000" => - -- JSR - LCycle <= "101"; - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDDI <= '1'; - Set_Addr_To <= "01"; -- S - when 2 => - Set_Addr_To <= "01"; -- S - Write_Data <= "111"; -- PCH - Write <= '1'; - when 3 => - Dec_S <= '1'; - Set_Addr_To <= "01"; -- S - Write_Data <= "110"; -- PCL - Write <= '1'; - when 4 => - Dec_S <= '1'; - when 5 => - Jump <= "10"; -- DIDL - when others => - end case; - when "01000000" => - -- RTI - LCycle <= "101"; - case to_integer(unsigned(MCycle)) is - when 1 => - Set_Addr_To <= "01"; -- S - when 2 => - Inc_S <= '1'; - Set_Addr_To <= "01"; -- S - when 3 => - Inc_S <= '1'; - Set_Addr_To <= "01"; -- S - Set_BusA_To <= "000"; -- DI - when 4 => - LDP <= '1'; - Inc_S <= '1'; - LDDI <= '1'; - Set_Addr_To <= "01"; -- S - when 5 => - Jump <= "10"; -- DIDL - when others => - end case; - when "01100000" => - -- RTS - LCycle <= "101"; - case to_integer(unsigned(MCycle)) is - when 1 => - Set_Addr_To <= "01"; -- S - when 2 => - Inc_S <= '1'; - Set_Addr_To <= "01"; -- S - when 3 => - Inc_S <= '1'; - LDDI <= '1'; - Set_Addr_To <= "01"; -- S - when 4 => - Jump <= "10"; -- DIDL - when 5 => - Jump <= "01"; - when others => - end case; - when "00001000" | "01001000" | "01011010" | "11011010" => - -- PHP, PHA, PHY*, PHX* - LCycle <= "010"; - if Mode = "00" and IR(1) = '1' then - LCycle <= "001"; - end if; - case to_integer(unsigned(MCycle)) is - when 1 => - case IR(7 downto 4) is - when "0000" => - Write_Data <= "101"; -- P - when "0100" => - Write_Data <= "001"; -- A - when "0101" => - Write_Data <= "011"; -- Y - when "1101" => - Write_Data <= "010"; -- X - when others => - end case; - Write <= '1'; - Set_Addr_To <= "01"; -- S - when 2 => - Dec_S <= '1'; - when others => - end case; - when "00101000" | "01101000" | "01111010" | "11111010" => - -- PLP, PLA, PLY*, PLX* - LCycle <= "011"; - if Mode = "00" and IR(1) = '1' then - LCycle <= "001"; - end if; - case IR(7 downto 4) is - when "0010" => - LDP <= '1'; - when "0110" => - LDA <= '1'; - when "0111" => - if Mode /= "00" then - LDY <= '1'; - end if; - when "1111" => - if Mode /= "00" then - LDX <= '1'; - end if; - when others => - end case; - case to_integer(unsigned(MCycle)) is - when 0 => - SaveP <= '1'; - when 1 => - Set_Addr_To <= "01"; -- S - when 2 => - Inc_S <= '1'; - Set_Addr_To <= "01"; -- S - when 3 => - Set_BusA_To <= "000"; -- DI - when others => - end case; - when "10100000" | "11000000" | "11100000" => - -- LDY, CPY, CPX - -- Immediate - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - when others => - end case; - when "10001000" => - -- DEY - LDY <= '1'; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Set_BusA_To <= "011"; -- Y - when others => - end case; - when "11001010" => - -- DEX - LDX <= '1'; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Set_BusA_To <= "010"; -- X - when others => - end case; - when "00011010" | "00111010" => - -- INC*, DEC* - if Mode /= "00" then - LDA <= '1'; -- A - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Set_BusA_To <= "100"; -- S - when others => - end case; - when "00001010" | "00101010" | "01001010" | "01101010" => - -- ASL, ROL, LSR, ROR - LDA <= '1'; -- A - Set_BusA_To <= "001"; -- A - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - when others => - end case; - when "10001010" | "10011000" => - -- TYA, TXA - LDA <= '1'; -- A - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - when others => - end case; - when "10101010" | "10101000" => - -- TAX, TAY - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Set_BusA_To <= "001"; -- A - when others => - end case; - when "10011010" => - -- TXS - case to_integer(unsigned(MCycle)) is - when 0 => - LDS <= '1'; - when 1 => - when others => - end case; - when "10111010" => - -- TSX - LDX <= '1'; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Set_BusA_To <= "100"; -- S - when others => - end case; + case IR(4 downto 0) is + -- IR: $00,$20,$40,$60,$80,$A0,$C0,$E0 + -- $08,$28,$48,$68,$88,$A8,$C8,$E8 + -- $0A,$2A,$4A,$6A,$8A,$AA,$CA,$EA + -- $18,$38,$58,$78,$98,$B8,$D8,$F8 + -- $1A,$3A,$5A,$7A,$9A,$BA,$DA,$FA + when "00000" | "01000" | "01010" | "11000" | "11010" => + -- Implied + case IR is + when x"00" => + -- BRK ($00) + lCycle <= Cycle_6; + case MCycle is + when Cycle_1 => + Set_Addr_To <= Set_Addr_To_SP; + Write_Data <= Write_Data_PCH; + Write <= '1'; + when Cycle_2 => + Dec_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + Write_Data <= Write_Data_PCL; + Write <= '1'; + when Cycle_3 => + Dec_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + Write_Data <= Write_Data_P; + Write <= '1'; + when Cycle_4 => + Dec_S <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_5 => + LDDI <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_6 => + Jump <= "10"; + when others => + end case; + when x"20" => -- JSR ($20) + lCycle <= Cycle_5; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDDI <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_2 => + Set_Addr_To <= Set_Addr_To_SP; + Write_Data <= Write_Data_PCH; + Write <= '1'; + when Cycle_3 => + Dec_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + Write_Data <= Write_Data_PCL; + Write <= '1'; + when Cycle_4 => + Dec_S <= '1'; + when Cycle_5 => + Jump <= "10"; + when others => + end case; + when x"40" => -- RTI ($40) + lCycle <= Cycle_5; + case MCycle is + when Cycle_1 => + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_2 => + Inc_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_3 => + Inc_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + Set_BusA_To <= Set_BusA_To_DI; + when Cycle_4 => + LDP <= '1'; + Inc_S <= '1'; + LDDI <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_5 => + Jump <= "10"; + when others => + end case; + when x"60" => -- RTS ($60) + lCycle <= Cycle_5; + case MCycle is + when Cycle_1 => + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_2 => + Inc_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_3 => + Inc_S <= '1'; + LDDI <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + when Cycle_4 => + Jump <= "10"; + when Cycle_5 => + Jump <= "01"; + when others => + end case; + when x"08" | x"48" | x"5a" | x"da" => -- PHP, PHA, PHY*, PHX* ($08,$48,$5A,$DA) + lCycle <= Cycle_2; + if Mode = "00" and IR(1) = '1' then--2 cycle nop + lCycle <= Cycle_1; + end if; + case MCycle is + when Cycle_1 => + if mode/="00" or IR(1)='0' then --wrong on 6502 + Write <= '1'; + case IR(7 downto 4) is + when "0000" => + Write_Data <= Write_Data_P; + when "0100" => + Write_Data <= Write_Data_ABC; + when "0101" => + if Mode /= "00" then + Write_Data <= Write_Data_Y; + else + Write <= '0'; + end if; + when "1101" => + if Mode /= "00" then + Write_Data <= Write_Data_X; + else + Write <= '0'; + end if; + when others => + end case; + Set_Addr_To <= Set_Addr_To_SP; + end if; + when Cycle_2 => + Dec_S <= '1'; + when others => + end case; + when x"28" | x"68" | x"7a" | x"fa" => -- PLP, PLA, PLY*, PLX* ($28,$68,$7A,$FA) + lCycle <= Cycle_3; + if Mode = "00" and IR(1) = '1' then--2 cycle nop + lCycle <= Cycle_1; + end if; + case IR(7 downto 4) is + when "0010" =>--plp + LDP <= '1'; + when "0110" =>--pla + LDA <= '1'; + when "0111" =>--ply not for 6502 + if Mode /= "00" then + LDY <= '1'; + end if; + when "1111" =>--plx not for 6502 + if Mode /= "00" then + LDX <= '1'; + end if; + when others => + end case; + case MCycle is + when Cycle_sync => + if Mode /= "00" or IR(1) = '0' then--wrong on 6502 + SaveP <= '1'; + end if; + when Cycle_1 => + if Mode /= "00" or IR(1) = '0' then--wrong on 6502 + Set_Addr_To <= Set_Addr_To_SP; + LDP <= '0'; + end if; + when Cycle_2 => + Inc_S <= '1'; + Set_Addr_To <= Set_Addr_To_SP; + LDP <= '0'; + when Cycle_3 => + Set_BusA_To <= Set_BusA_To_DI; + when others => + end case; + when x"a0" | x"c0" | x"e0" => -- LDY, CPY, CPX ($A0,$C0,$E0) + -- Immediate + case MCycle is + when Cycle_sync => + when Cycle_1 => + Jump <= "01"; + when others => + end case; + when x"88" => -- DEY ($88) + LDY <= '1'; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Set_BusA_To <= Set_BusA_To_Y; + when others => + end case; + when x"ca" => -- DEX ($CA) + LDX <= '1'; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Set_BusA_To <= Set_BusA_To_X; + when others => + end case; + when x"1a" | x"3a" => -- INC*, DEC* ($1A,$3A) + if Mode /= "00" then + LDA <= '1'; -- A + else + lCycle <= Cycle_1;--undoc 2 cycle nop + end if; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Set_BusA_To <= Set_BusA_To_S; + when others => + end case; + when x"0a" | x"2a" | x"4a" | x"6a" => -- ASL, ROL, LSR, ROR ($0A,$2A,$4A,$6A) + LDA <= '1'; -- A + Set_BusA_To <= Set_BusA_To_ABC; + case MCycle is + when Cycle_sync => + when Cycle_1 => + when others => + end case; + when x"8a" | x"98" => -- TYA, TXA ($8A,$98) + LDA <= '1'; + case MCycle is + when Cycle_sync => + when Cycle_1 => + when others => + end case; + when x"aa" | x"a8" => -- TAX, TAY ($AA,$A8) + case MCycle is + when Cycle_sync => + when Cycle_1 => + Set_BusA_To <= Set_BusA_To_ABC; + when others => + end case; + when x"9a" => -- TXS ($9A) + LDS <= '1'; -- will be set only in Cycle_sync + when x"ba" => -- TSX ($BA) + LDX <= '1'; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Set_BusA_To <= Set_BusA_To_S; + when others => + end case; + when x"80" => -- undoc: NOP imm2 ($80) + case MCycle is + when Cycle_sync => + when Cycle_1 => + Jump <= "01"; + when others => + end case; + when others => -- others ($0A,$EA, $18,$38,$58,$78,$B8,$C8,$D8,$E8,$F8) + case MCycle is + when Cycle_sync => + when others => + end case; + end case; - -- when "00011000" | "00111000" | "01011000" | "01111000" | "10111000" | "11011000" | "11111000" | "11001000" | "11101000" => - -- -- CLC, SEC, CLI, SEI, CLV, CLD, SED, INY, INX - -- case to_integer(unsigned(MCycle)) is - -- when 1 => - -- when others => - -- end case; - when others => - case to_integer(unsigned(MCycle)) is - when 0 => - when others => - end case; - end case; - --}}} + -- IR: $01,$21,$41,$61,$81,$A1,$C1,$E1 + -- $03,$23,$43,$63,$83,$A3,$C3,$E3 + when "00001" | "00011" => + -- Zero Page Indexed Indirect (d,x) + lCycle <= Cycle_5; + if IR(7 downto 6) /= "10" then -- ($01,$21,$41,$61,$C1,$E1,$03,$23,$43,$63,$C3,$E3) + LDA <= '1'; + if Mode="00" and IR(1)='1' then + lCycle <= Cycle_7; + end if; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + ADAdd <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_3 => + BAAdd <= "01"; + LDBAL <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_4 => + LDBAH <= '1'; + if IR(7 downto 5) = "100" then + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_5=> + if Mode="00" and IR(1)='1' and IR(7 downto 6)/="10" then + Set_Addr_To <= Set_Addr_To_BA; + Write <= '1'; + LDDI<='1'; + end if; + when Cycle_6=> + Write <= '1'; + LDALU<='1'; + SaveP<='1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_7 => + ALUmore <= '1'; + Set_BusA_To <= Set_BusA_To_ABC; + when others => + end case; - when "00001" | "00011" => - --{{{ - -- Zero Page Indexed Indirect (d,x) - LCycle <= "101"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDAD <= '1'; - Set_Addr_To <= "10"; -- AD - when 2 => - ADAdd <= '1'; - Set_Addr_To <= "10"; -- AD - when 3 => - BAAdd <= "01"; -- DB Inc - LDBAL <= '1'; - Set_Addr_To <= "10"; -- AD - when 4 => - LDBAH <= '1'; - if IR(7 downto 5) = "100" then - Write <= '1'; - end if; - Set_Addr_To <= "11"; -- BA - when 5 => - when others => - end case; - --}}} + -- IR: $09,$29,$49,$69,$89,$A9,$C9,$E9 + when "01001" => + -- Immediate + if IR(7 downto 5)/="100" then -- all except undoc. NOP imm2 (not $89) + LDA <= '1'; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + when others => + end case; - when "01001" | "01011" => - --{{{ - -- Immediate - LDA <= '1'; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - when others => - end case; + -- IR: $0B,$2B,$4B,$6B,$8B,$AB,$CB,$EB + when "01011" => + if Mode="00" then + -- Immediate undoc for 6500 + case IR(7 downto 5) is + when "010"|"011"|"000"|"001" =>--ALR,ARR + Set_BusA_To<=Set_BusA_To_DA; + LDA <= '1'; + when "100" =>--XAA + Set_BusA_To<=Set_BusA_To_DAX; + LDA <= '1'; + when "110" =>--SAX (SBX) + Set_BusA_To<=Set_BusA_To_AAX; + LDX <= '1'; + when "101" =>--OAL + Set_BusA_To<=Set_BusA_To_DAO; + LDA <= '1'; + when others=> + LDA <= '1'; + end case; + case MCycle is + when Cycle_1 => + Jump <= "01"; + when others => + end case; + end if; - --}}} + -- IR: $02,$22,$42,$62,$82,$A2,$C2,$E2 + -- $12,$32,$52,$72,$92,$B2,$D2,$F2 + when "00010" | "10010" => + -- Immediate, SKB, KIL + case MCycle is + when Cycle_sync => + when Cycle_1 => + if IR = "10100010" then + -- LDX ($A2) + Jump <= "01"; + LDX <= '1'; -- Moved, Lorenz test showed X changing on SKB (NOPx) + elsif IR(7 downto 4)="1000" or IR(7 downto 4)="1100" or IR(7 downto 4)="1110" then + -- undoc: NOP imm2 + Jump <= "01"; + else + -- KIL !!! + end if; + when others => + end case; - when "00010" | "10010" => - --{{{ - -- Immediate, KIL - LDX <= '1'; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - if IR = "10100010" then - -- LDX - Jump <= "01"; - else - -- KIL !!!!!!!!!!!!!!!!!!!!!!!!!!!!! - end if; - when others => - end case; - --}}} + -- IR: $04,$24,$44,$64,$84,$A4,$C4,$E4 + when "00100" => + -- Zero Page + lCycle <= Cycle_2; + case MCycle is + when Cycle_sync => + if IR(7 downto 5) = "001" then--24=BIT zpg + SaveP <= '1'; + end if; + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + if IR(7 downto 5) = "100" then--84=sty zpg (the only write in this group) + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + when others => + end case; - when "00100" => - --{{{ - -- Zero Page - LCycle <= "010"; - case to_integer(unsigned(MCycle)) is - when 0 => - if IR(7 downto 5) = "001" then - SaveP <= '1'; - end if; - when 1 => - Jump <= "01"; - LDAD <= '1'; - if IR(7 downto 5) = "100" then - Write <= '1'; - end if; - Set_Addr_To <= "10"; -- AD - when 2 => - when others => - end case; - --}}} + -- IR: $05,$25,$45,$65,$85,$A5,$C5,$E5 + -- $06,$26,$46,$66,$86,$A6,$C6,$E6 + -- $07,$27,$47,$67,$87,$A7,$C7,$E7 + when "00101" | "00110" | "00111" => + -- Zero Page + if IR(7 downto 6) /= "10" and IR(1) = '1' and (mode="00" or IR(0)='0') then--covers 0x-7x,cx-fx x=2,3,6,7,a,b,e,f, for 6502 undocs + -- Read-Modify-Write + lCycle <= Cycle_4; + if Mode="00" and IR(0)='1' then + LDA<='1'; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + LDDI <= '1'; + if Mode="00" then--The old 6500 writes back what is just read, before changing. The 65c does another read + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_3 => + LDALU <= '1'; + SaveP <= '1'; + Write <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_4 => + if Mode="00" and IR(0)='1' then + Set_BusA_To<=Set_BusA_To_ABC; + ALUmore <= '1'; -- For undoc DCP/DCM support + LDDI <= '1'; -- requires DIN to reflect DOUT! + end if; + when others => + end case; + else + lCycle <= Cycle_2; + if IR(7 downto 6) /= "10" then + LDA <= '1'; + end if; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + if IR(7 downto 5) = "100" then + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + when others => + end case; + end if; - when "00101" | "00110" | "00111" => - --{{{ - -- Zero Page - if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then - -- Read-Modify-Write - LCycle <= "100"; - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDAD <= '1'; - Set_Addr_To <= "10"; -- AD - when 2 => - LDDI <= '1'; - Write <= '1'; - Set_Addr_To <= "10"; -- AD - when 3 => - LDALU <= '1'; - SaveP <= '1'; - Write <= '1'; - Set_Addr_To <= "10"; -- AD - when 4 => - when others => - end case; - else - LCycle <= "010"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDAD <= '1'; - if IR(7 downto 5) = "100" then - Write <= '1'; - end if; - Set_Addr_To <= "10"; -- AD - when 2 => - when others => - end case; - end if; - --}}} + -- IR: $0C,$2C,$4C,$6C,$8C,$AC,$CC,$EC + when "01100" => + -- Absolute + if IR(7 downto 6) = "01" and IR(4 downto 0) = "01100" then -- JMP ($4C,$6C) + if IR(5) = '0' then + lCycle <= Cycle_2; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDDI <= '1'; + when Cycle_2 => + Jump <= "10"; + when others => + end case; + else + lCycle <= Cycle_4; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDDI <= '1'; + LDBAL <= '1'; + when Cycle_2 => + LDBAH <= '1'; + if Mode /= "00" then + Jump <= "10"; + end if; + if Mode = "00" then + Set_Addr_To <= Set_Addr_To_BA; + end if; + when Cycle_3 => + LDDI <= '1'; + if Mode = "00" then + Set_Addr_To <= Set_Addr_To_BA; + BAAdd <= "01"; -- DB Inc + else + Jump <= "01"; + end if; + when Cycle_4 => + Jump <= "10"; + when others => + end case; + end if; + else + lCycle <= Cycle_3; + case MCycle is + when Cycle_sync => + if IR(7 downto 5) = "001" then--2c-BIT + SaveP <= '1'; + end if; + when Cycle_1 => + Jump <= "01"; + LDBAL <= '1'; + when Cycle_2 => + Jump <= "01"; + LDBAH <= '1'; + if IR(7 downto 5) = "100" then--80, sty, the only write in this group + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_3 => + when others => + end case; + end if; - when "01100" => - --{{{ - -- Absolute - if IR(7 downto 6) = "01" and IR(4 downto 0) = "01100" then - -- JMP - if IR(5) = '0' then - --LCycle <= "011"; - LCycle <= "010"; - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDDI <= '1'; - when 2 => - Jump <= "10"; -- DIDL - when others => - end case; - else - --LCycle <= "101"; - LCycle <= "100"; -- mikej - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDDI <= '1'; - LDBAL <= '1'; - when 2 => - LDBAH <= '1'; - if Mode /= "00" then - Jump <= "10"; -- DIDL - end if; - if Mode = "00" then - Set_Addr_To <= "11"; -- BA - end if; - when 3 => - LDDI <= '1'; - if Mode = "00" then - Set_Addr_To <= "11"; -- BA - BAAdd <= "01"; -- DB Inc - else - Jump <= "01"; - end if; - when 4 => - Jump <= "10"; -- DIDL - when others => - end case; - end if; - else - LCycle <= "011"; - case to_integer(unsigned(MCycle)) is - when 0 => - if IR(7 downto 5) = "001" then - SaveP <= '1'; - end if; - when 1 => - Jump <= "01"; - LDBAL <= '1'; - when 2 => - Jump <= "01"; - LDBAH <= '1'; - if IR(7 downto 5) = "100" then - Write <= '1'; - end if; - Set_Addr_To <= "11"; -- BA - when 3 => - when others => - end case; - end if; - --}}} + -- IR: $0D,$2D,$4D,$6D,$8D,$AD,$CD,$ED + -- $0E,$2E,$4E,$6E,$8E,$AE,$CE,$EE + -- $0F,$2F,$4F,$6F,$8F,$AF,$CF,$EF + when "01101" | "01110" | "01111" => + -- Absolute + if IR(7 downto 6) /= "10" and IR(1) = '1' and (mode="00" or IR(0)='0') then -- ($0E,$2E,$4E,$6E,$CE,$EE, $0F,$2F,$4F,$6F,$CF,$EF) + -- Read-Modify-Write + lCycle <= Cycle_5; + if Mode="00" and IR(0) = '1' then + LDA <= '1'; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDBAL <= '1'; + when Cycle_2 => + Jump <= "01"; + LDBAH <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_3 => + LDDI <= '1'; + if Mode="00" then--The old 6500 writes back what is just read, before changing. The 65c does another read + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_4 => + Write <= '1'; + LDALU <= '1'; + SaveP <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_5 => + if Mode="00" and IR(0)='1' then + ALUmore <= '1'; -- For undoc DCP/DCM support + Set_BusA_To<=Set_BusA_To_ABC; + end if; + when others => + end case; + else + lCycle <= Cycle_3; + if IR(7 downto 6) /= "10" then -- all but $8D, $8E, $8F, $AD, $AE, $AF ($AD does set LDA in an earlier case statement) + LDA <= '1'; + end if; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Jump <= "01"; + LDBAL <= '1'; + when Cycle_2 => + Jump <= "01"; + LDBAH <= '1'; + if IR(7 downto 5) = "100" then--8d + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_3 => + when others => + end case; + end if; - when "01101" | "01110" | "01111" => - --{{{ - -- Absolute - if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then - -- Read-Modify-Write - LCycle <= "101"; - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDBAL <= '1'; - when 2 => - Jump <= "01"; - LDBAH <= '1'; - Set_Addr_To <= "11"; -- BA - when 3 => - LDDI <= '1'; - Write <= '1'; - Set_Addr_To <= "11"; -- BA - when 4 => - Write <= '1'; - LDALU <= '1'; - SaveP <= '1'; - Set_Addr_To <= "11"; -- BA - when 5 => - SaveP <= '0'; -- MIKEJ was 1 - when others => - end case; - else - LCycle <= "011"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDBAL <= '1'; - when 2 => - Jump <= "01"; - LDBAH <= '1'; - if IR(7 downto 5) = "100" then - Write <= '1'; - end if; - Set_Addr_To <= "11"; -- BA - when 3 => - when others => - end case; - end if; - --}}} + -- IR: $10,$30,$50,$70,$90,$B0,$D0,$F0 + when "10000" => + -- Relative + -- This circuit dictates when the last + -- microcycle occurs for the branch depending on + -- whether or not the branch is taken and if a page + -- is crossed... + if (Branch = '1') then + lCycle <= Cycle_3; -- We're done @ T3 if branching...upper + -- level logic will stop at T2 if no page cross + -- (See the Break signal) + else + lCycle <= Cycle_1; + end if; + -- This decodes the current microcycle and takes the + -- proper course of action... + case MCycle is + -- On the T1 microcycle, increment the program counter + -- and instruct the upper level logic to fetch the offset + -- from the Din bus and store it in the data latches. This + -- will be the last microcycle if the branch isn't taken. + when Cycle_1 => + Jump <= "01"; -- Increments the PC by one (PC will now be PC+2) + -- from microcycle T0. + LDDI <= '1'; -- Tells logic in top level (T65.vhd) to route + -- the Din bus to the memory data latch (DL) + -- so that the branch offset is fetched. + -- In microcycle T2, tell the logic in the top level to + -- add the offset. If the most significant byte of the + -- program counter (i.e. the current "page") does not need + -- updating, we are done here...the Break signal at the + -- T65.vhd level takes care of that... + when Cycle_2 => + Jump <= "11"; -- Tell the PC Jump logic to use relative mode. + PCAdd <= '1'; -- This tells the PC adder to update itself with + -- the current offset recently fetched from + -- memory. + -- The following is microcycle T3 : + -- The program counter should be completely updated + -- on this cycle after the page cross is detected. + -- We don't need to do anything here... + when Cycle_3 => + when others => null; -- Do nothing. + end case; - when "10000" => - --{{{ - -- Relative + -- IR: $11,$31,$51,$71,$91,$B1,$D1,$F1 + -- $13,$33,$53,$73,$93,$B3,$D3,$F3 + when "10001" | "10011" => + lCycle <= Cycle_5; + if IR(7 downto 6) /= "10" then -- ($11,$31,$51,$71,$D1,$F1,$13,$33,$53,$73,$D3,$F3) + LDA <= '1'; + if Mode="00" and IR(1)='1' then + lCycle <= Cycle_7; + end if; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + LDBAL <= '1'; + BAAdd <= "01"; -- DB Inc + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_3 => + Set_BusA_To <= Set_BusA_To_Y; + BAAdd <= "10"; -- BA Add + LDBAH <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_4 => + BAAdd <= "11"; -- BA Adj + if IR(7 downto 5) = "100" then + Write <= '1'; + elsif IR(1)='0' or IR=x"B3" then -- Dont do this on $x3, except undoc LAXiy $B3 (says real CPU and Lorenz tests) + BreakAtNA <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_5 => + if Mode="00" and IR(1)='1' and IR(7 downto 6)/="10" then + Set_Addr_To <= Set_Addr_To_BA; + LDDI<='1'; + Write <= '1'; + end if; + when Cycle_6 => + LDALU<='1'; + SaveP<='1'; + Write <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_7 => + ALUmore <= '1'; + Set_BusA_To<=Set_BusA_To_ABC; + when others => + end case; - -- This circuit dictates when the last - -- microcycle occurs for the branch depending on - -- whether or not the branch is taken and if a page - -- is crossed... - if (Branch = '1') then + -- IR: $14,$34,$54,$74,$94,$B4,$D4,$F4 + -- $15,$35,$55,$75,$95,$B5,$D5,$F5 + -- $16,$36,$56,$76,$96,$B6,$D6,$F6 + -- $17,$37,$57,$77,$97,$B7,$D7,$F7 + when "10100" | "10101" | "10110" | "10111" => + -- Zero Page, X + if IR(7 downto 6) /= "10" and IR(1) = '1' and (Mode="00" or IR(0)='0') then -- ($16,$36,$56,$76,$D6,$F6, $17,$37,$57,$77,$D7,$F7) + -- Read-Modify-Write + if Mode="00" and IR(0)='1' then + LDA<='1'; + end if; + lCycle <= Cycle_5; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + ADAdd <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_3 => + LDDI <= '1'; + if Mode="00" then -- The old 6500 writes back what is just read, before changing. The 65c does another read + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_4 => + LDALU <= '1'; + SaveP <= '1'; + Write <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + if Mode="00" and IR(0)='1' then + LDDI<='1'; + end if; + when Cycle_5 => + if Mode="00" and IR(0)='1' then + ALUmore <= '1'; -- For undoc DCP/DCM support + Set_BusA_To<=Set_BusA_To_ABC; + end if; + when others => + end case; + else + lCycle <= Cycle_3; + if IR(7 downto 6) /= "10" and IR(0)='1' then -- dont LDA on undoc skip + LDA <= '1'; + end if; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Jump <= "01"; + LDAD <= '1'; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_2 => + ADAdd <= '1'; + -- Added this check for Y reg. use, added undocs + if (IR(3 downto 1) = "011") then -- ($16,$36,$56,$76,$96,$B6,$D6,$F6,$17,$37,$57,$77,$97,$B7,$D7,$F7) + AddY <= '1'; + end if; + if IR(7 downto 5) = "100" then -- ($14,$34,$15,$35,$16,$36,$17,$37) the only write instruction + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_ZPG; + when Cycle_3 => null; + when others => + end case; + end if; - LCycle <= "011"; -- We're done @ T3 if branching...upper - -- level logic will stop at T2 if no page cross - -- (See the Break signal) - else + -- IR: $19,$39,$59,$79,$99,$B9,$D9,$F9 + -- $1B,$3B,$5B,$7B,$9B,$BB,$DB,$FB + when "11001" | "11011" => + -- Absolute Y + lCycle <= Cycle_4; + if IR(7 downto 6) /= "10" then + LDA <= '1'; + if Mode="00" and IR(1)='1' then + lCycle <= Cycle_6; + end if; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDBAL <= '1'; + when Cycle_2 => + Jump <= "01"; + Set_BusA_To <= Set_BusA_To_Y; + BAAdd <= "10"; -- BA Add + LDBAH <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_3 => + BAAdd <= "11"; -- BA adj + if IR(7 downto 5) = "100" then--99/9b + Write <= '1'; + elsif IR(1)='0' or IR=x"BB" then -- Dont do this on $xB, except undoc $BB (says real CPU and Lorenz tests) + BreakAtNA <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_4 => -- just for undoc + if Mode="00" and IR(1)='1' and IR(7 downto 6)/="10" then + Set_Addr_To <= Set_Addr_To_BA; + LDDI<='1'; + Write <= '1'; + end if; + when Cycle_5 => + Write <= '1'; + LDALU<='1'; + Set_Addr_To <= Set_Addr_To_BA; + SaveP<='1'; + when Cycle_6 => + ALUmore <= '1'; + Set_BusA_To <= Set_BusA_To_ABC; + when others => + end case; - LCycle <= "001"; + -- IR: $1C,$3C,$5C,$7C,$9C,$BC,$DC,$FC + -- $1D,$3D,$5D,$7D,$9D,$BD,$DD,$FD + -- $1E,$3E,$5E,$7E,$9E,$BE,$DE,$FE + -- $1F,$3F,$5F,$7F,$9F,$BF,$DF,$FF + when "11100" | "11101" | "11110" | "11111" => + -- Absolute X + if IR(7 downto 6) /= "10" and IR(1) = '1' and (Mode="00" or IR(0)='0') then -- ($1E,$3E,$5E,$7E,$DE,$FE, $1F,$3F,$5F,$7F,$DF,$FF) + -- Read-Modify-Write + lCycle <= Cycle_6; + if Mode="00" and IR(0)='1' then + LDA <= '1'; + end if; + case MCycle is + when Cycle_1 => + Jump <= "01"; + LDBAL <= '1'; + when Cycle_2 => + Jump <= "01"; + Set_BusA_To <= Set_BusA_To_X; + BAAdd <= "10"; -- BA Add + LDBAH <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_3 => + BAAdd <= "11"; -- BA adj + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_4 => + LDDI <= '1'; + if Mode="00" then--The old 6500 writes back what is just read, before changing. The 65c does another read + Write <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_5 => + LDALU <= '1'; + SaveP <= '1'; + Write <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_6 => + if Mode="00" and IR(0)='1' then + ALUmore <= '1'; + Set_BusA_To <= Set_BusA_To_ABC; + end if; + when others => + end case; + else -- ($1C,$3C,$5C,$7C,$9C,$BC,$DC,$FC, $1D,$3D,$5D,$7D,$9D,$BD,$DD,$FD, $9E,$BE,$9F,$BF) + lCycle <= Cycle_4;--Or 3 if not page crossing + if IR(7 downto 6) /= "10" then + if Mode/="00" or IR(4)='0' or IR(1 downto 0)/="00" then + LDA <= '1'; + end if; + end if; + case MCycle is + when Cycle_sync => + when Cycle_1 => + Jump <= "01"; + LDBAL <= '1'; + when Cycle_2 => + Jump <= "01"; + -- special case $BE which uses Y reg as index!! + if(IR(7 downto 6)="10" and IR(4 downto 1)="1111") then + Set_BusA_To <= Set_BusA_To_Y; + else + Set_BusA_To <= Set_BusA_To_X; + end if; + BAAdd <= "10"; -- BA Add + LDBAH <= '1'; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_3 => + BAAdd <= "11"; -- BA adj + if IR(7 downto 5) = "100" then -- ($9E,$9F) + Write <= '1'; + else + BreakAtNA <= '1'; + end if; + Set_Addr_To <= Set_Addr_To_BA; + when Cycle_4 => + when others => + end case; + end if; + when others => + end case; + end process; - end if; + process (IR, MCycle, Mode,ALUmore) + begin + -- ORA, AND, EOR, ADC, NOP, LD, CMP, SBC + -- ASL, ROL, LSR, ROR, BIT, LD, DEC, INC + case IR(1 downto 0) is + when "00" => + case IR(4 downto 2) is + -- IR: $00,$20,$40,$60,$80,$A0,$C0,$E0 + -- $04,$24,$44,$64,$84,$A4,$C4,$E4 + -- $0C,$2C,$4C,$6C,$8C,$AC,$CC,$EC + when "000" | "001" | "011" => + case IR(7 downto 5) is + when "110" | "111" => -- CP ($C0,$C4,$CC,$E0,$E4,$EC) + ALU_Op <= ALU_OP_CMP; + when "101" => -- LD ($A0,$A4,$AC) + ALU_Op <= ALU_OP_EQ2; + when "001" => -- BIT ($20,$24,$2C - $20 is ignored, as its a jmp) + ALU_Op <= ALU_OP_BIT; + when others => -- other, NOP/ST ($x0,$x4,$xC) + ALU_Op <= ALU_OP_EQ1; + end case; - -- This decodes the current microcycle and takes the - -- proper course of action... - case to_integer(unsigned(MCycle)) is + -- IR: $08,$28,$48,$68,$88,$A8,$C8,$E8 + when "010" => + case IR(7 downto 5) is + when "111" | "110" => -- IN ($C8,$E8) + ALU_Op <= ALU_OP_INC; + when "100" => -- DEY ($88) + ALU_Op <= ALU_OP_DEC; + when others => -- LD + ALU_Op <= ALU_OP_EQ2; + end case; - -- On the T1 microcycle, increment the program counter - -- and instruct the upper level logic to fetch the offset - -- from the Din bus and store it in the data latches. This - -- will be the last microcycle if the branch isn't taken. - when 1 => + -- IR: $18,$38,$58,$78,$98,$B8,$D8,$F8 + when "110" => + case IR(7 downto 5) is + when "100" => -- TYA ($98) + ALU_Op <= ALU_OP_EQ2; + when others => + ALU_Op <= ALU_OP_EQ1; + end case; - Jump <= "01"; -- Increments the PC by one (PC will now be PC+2) - -- from microcycle T0. + -- IR: $10,$30,$50,$70,$90,$B0,$D0,$F0 + -- $14,$34,$54,$74,$94,$B4,$D4,$F4 + -- $1C,$3C,$5C,$7C,$9C,$BC,$DC,$FC + when others => + case IR(7 downto 5) is + when "101" => -- LD ($B0,$B4,$BC) + ALU_Op <= ALU_OP_EQ2; + when others => + ALU_Op <= ALU_OP_EQ1; + end case; + end case; - LDDI <= '1'; -- Tells logic in top level (T65.vhd) to route - -- the Din bus to the memory data latch (DL) - -- so that the branch offset is fetched. + when "01" => -- OR + case(to_integer(unsigned(IR(7 downto 5)))) is + when 0=> -- IR: $01,$05,$09,$0D,$11,$15,$19,$1D + ALU_Op<=ALU_OP_OR; + when 1=> -- IR: $21,$25,$29,$2D,$31,$35,$39,$3D + ALU_Op<=ALU_OP_AND; + when 2=> -- IR: $41,$45,$49,$4D,$51,$55,$59,$5D + ALU_Op<=ALU_OP_EOR; + when 3=> -- IR: $61,$65,$69,$6D,$71,$75,$79,$7D + ALU_Op<=ALU_OP_ADC; + when 4=>-- IR: $81,$85,$89,$8D,$91,$95,$99,$9D + ALU_Op<=ALU_OP_EQ1; -- STA + when 5=> -- IR: $A1,$A5,$A9,$AD,$B1,$B5,$B9,$BD + ALU_Op<=ALU_OP_EQ2; -- LDA + when 6=> -- IR: $C1,$C5,$C9,$CD,$D1,$D5,$D9,$DD + ALU_Op<=ALU_OP_CMP; + when others=> -- IR: $E1,$E5,$E9,$ED,$F1,$F5,$F9,$FD + ALU_Op<=ALU_OP_SBC; + end case; - -- In microcycle T2, tell the logic in the top level to - -- add the offset. If the most significant byte of the - -- program counter (i.e. the current "page") does not need - -- updating, we are done here...the Break signal at the - -- T65.vhd level takes care of that... - when 2 => + when "10" => + case(to_integer(unsigned(IR(7 downto 5)))) is + when 0=> -- IR: $02,$06,$0A,$0E,$12,$16,$1A,$1E + ALU_Op<=ALU_OP_ASL; + if IR(4 downto 2) = "110" and Mode/="00" then -- 00011010,$1A -> INC acc, not on 6502 + ALU_Op <= ALU_OP_INC; + end if; + when 1=> -- IR: $22,$26,$2A,$2E,$32,$36,$3A,$3E + ALU_Op<=ALU_OP_ROL; + if IR(4 downto 2) = "110" and Mode/="00" then -- 00111010,$3A -> DEC acc, not on 6502 + ALU_Op <= ALU_OP_DEC; + end if; + when 2=> -- IR: $42,$46,$4A,$4E,$52,$56,$5A,$5E + ALU_Op<=ALU_OP_LSR; + when 3=> -- IR: $62,$66,$6A,$6E,$72,$76,$7A,$7E + ALU_Op<=ALU_OP_ROR; + when 4=> -- IR: $82,$86,$8A,$8E,$92,$96,$9A,$9E + ALU_Op<=ALU_OP_BIT; + if IR(4 downto 2) = "010" then -- 10001010, $8A -> TXA + ALU_Op <= ALU_OP_EQ2; + else -- 100xxx10, $82,$86,$8E,$92,$96,$9A,$9E + ALU_Op <= ALU_OP_EQ1; + end if; + when 5=> -- IR: $A2,$A6,$AA,$AE,$B2,$B6,$BA,$BE + ALU_Op<=ALU_OP_EQ2; -- LDX + when 6=> -- IR: $C2,$C6,$CA,$CE,$D2,$D6,$DA,$DE + ALU_Op<=ALU_OP_DEC; + when others=> -- IR: $E2,$E6,$EA,$EE,$F2,$F6,$FA,$FE + ALU_Op<=ALU_OP_INC; + end case; - Jump <= "11"; -- Tell the PC Jump logic to use relative mode. + when others => -- "11" undoc double alu ops + case(to_integer(unsigned(IR(7 downto 5)))) is + -- IR: $A3,$A7,$AB,$AF,$B3,$B7,$BB,$BF + when 5 => + if IR=x"bb" then--LAS + ALU_Op <= ALU_OP_AND; + else + ALU_Op <= ALU_OP_EQ2; + end if; - PCAdd <= '1'; -- This tells the PC adder to update itself with - -- the current offset recently fetched from - -- memory. - - -- The following is microcycle T3 : - -- The program counter should be completely updated - -- on this cycle after the page cross is detected. - -- We don't need to do anything here... - when 3 => - - - when others => null; -- Do nothing. - - end case; - --}}} - - when "10001" | "10011" => - --{{{ - -- Zero Page Indirect Indexed (d),y - LCycle <= "101"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDAD <= '1'; - Set_Addr_To <= "10"; -- AD - when 2 => - LDBAL <= '1'; - BAAdd <= "01"; -- DB Inc - Set_Addr_To <= "10"; -- AD - when 3 => - Set_BusA_To <= "011"; -- Y - BAAdd <= "10"; -- BA Add - LDBAH <= '1'; - Set_Addr_To <= "11"; -- BA - when 4 => - BAAdd <= "11"; -- BA Adj - if IR(7 downto 5) = "100" then - Write <= '1'; - else - BreakAtNA <= '1'; - end if; - Set_Addr_To <= "11"; -- BA - when 5 => - when others => - end case; - --}}} - - when "10100" | "10101" | "10110" | "10111" => - --{{{ - -- Zero Page, X - if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then - -- Read-Modify-Write - LCycle <= "101"; - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDAD <= '1'; - Set_Addr_To <= "10"; -- AD - when 2 => - ADAdd <= '1'; - Set_Addr_To <= "10"; -- AD - when 3 => - LDDI <= '1'; - Write <= '1'; - Set_Addr_To <= "10"; -- AD - when 4 => - LDALU <= '1'; - SaveP <= '1'; - Write <= '1'; - Set_Addr_To <= "10"; -- AD - when 5 => - when others => - end case; - else - LCycle <= "011"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDAD <= '1'; - Set_Addr_To <= "10"; -- AD - when 2 => - ADAdd <= '1'; - -- Added this check for Y reg. use... - if (IR(3 downto 0) = "0110") then - AddY <= '1'; - end if; - - if IR(7 downto 5) = "100" then - Write <= '1'; - end if; - Set_Addr_To <= "10"; -- AD - when 3 => null; - when others => - end case; - end if; - --}}} - - when "11001" | "11011" => - --{{{ - -- Absolute Y - LCycle <= "100"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDBAL <= '1'; - when 2 => - Jump <= "01"; - Set_BusA_To <= "011"; -- Y - BAAdd <= "10"; -- BA Add - LDBAH <= '1'; - Set_Addr_To <= "11"; -- BA - when 3 => - BAAdd <= "11"; -- BA adj - if IR(7 downto 5) = "100" then - Write <= '1'; - else - BreakAtNA <= '1'; - end if; - Set_Addr_To <= "11"; -- BA - when 4 => - when others => - end case; - --}}} - - when "11100" | "11101" | "11110" | "11111" => - --{{{ - -- Absolute X - - if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then - -- Read-Modify-Write - LCycle <= "110"; - case to_integer(unsigned(MCycle)) is - when 1 => - Jump <= "01"; - LDBAL <= '1'; - when 2 => - Jump <= "01"; - Set_BusA_To <= "010"; -- X - BAAdd <= "10"; -- BA Add - LDBAH <= '1'; - Set_Addr_To <= "11"; -- BA - when 3 => - BAAdd <= "11"; -- BA adj - Set_Addr_To <= "11"; -- BA - when 4 => - LDDI <= '1'; - Write <= '1'; - Set_Addr_To <= "11"; -- BA - when 5 => - LDALU <= '1'; - SaveP <= '1'; - Write <= '1'; - Set_Addr_To <= "11"; -- BA - when 6 => - when others => - end case; - else - LCycle <= "100"; - if IR(7 downto 6) /= "10" then - LDA <= '1'; - end if; - case to_integer(unsigned(MCycle)) is - when 0 => - when 1 => - Jump <= "01"; - LDBAL <= '1'; - when 2 => - Jump <= "01"; - -- mikej - -- special case 0xBE which uses Y reg as index!! - if (IR = "10111110") then - Set_BusA_To <= "011"; -- Y - else - Set_BusA_To <= "010"; -- X - end if; - BAAdd <= "10"; -- BA Add - LDBAH <= '1'; - Set_Addr_To <= "11"; -- BA - when 3 => - BAAdd <= "11"; -- BA adj - if IR(7 downto 5) = "100" then - Write <= '1'; - else - BreakAtNA <= '1'; - end if; - Set_Addr_To <= "11"; -- BA - when 4 => - when others => - end case; - end if; - --}}} - when others => - end case; - end process; - - process (IR, MCycle) - begin - -- ORA, AND, EOR, ADC, NOP, LD, CMP, SBC - -- ASL, ROL, LSR, ROR, BIT, LD, DEC, INC - case IR(1 downto 0) is - when "00" => - --{{{ - case IR(4 downto 2) is - when "000" | "001" | "011" => - case IR(7 downto 5) is - when "110" | "111" => - -- CP - ALU_Op <= "0110"; - when "101" => - -- LD - ALU_Op <= "0101"; - when "001" => - -- BIT - ALU_Op <= "1100"; - when others => - -- NOP/ST - ALU_Op <= "0100"; - end case; - when "010" => - case IR(7 downto 5) is - when "111" | "110" => - -- IN - ALU_Op <= "1111"; - when "100" => - -- DEY - ALU_Op <= "1110"; - when others => - -- LD - ALU_Op <= "1101"; - end case; - when "110" => - case IR(7 downto 5) is - when "100" => - -- TYA - ALU_Op <= "1101"; - when others => - ALU_Op <= "----"; - end case; - when others => - case IR(7 downto 5) is - when "101" => - -- LD - ALU_Op <= "1101"; - when others => - ALU_Op <= "0100"; - end case; - end case; - --}}} - when "01" => -- OR - --{{{ - ALU_Op(3) <= '0'; - ALU_Op(2 downto 0) <= IR(7 downto 5); - --}}} - when "10" => - --{{{ - ALU_Op(3) <= '1'; - ALU_Op(2 downto 0) <= IR(7 downto 5); - case IR(7 downto 5) is - when "000" => - if IR(4 downto 2) = "110" then - -- INC - ALU_Op <= "1111"; - end if; - when "001" => - if IR(4 downto 2) = "110" then - -- DEC - ALU_Op <= "1110"; - end if; - when "100" => - if IR(4 downto 2) = "010" then - -- TXA - ALU_Op <= "0101"; - else - ALU_Op <= "0100"; - end if; - when others => - end case; - --}}} - when others => - --{{{ - case IR(7 downto 5) is - when "100" => - ALU_Op <= "0100"; - when others => - if MCycle = "000" then - ALU_Op(3) <= '0'; - ALU_Op(2 downto 0) <= IR(7 downto 5); - else - ALU_Op(3) <= '1'; - ALU_Op(2 downto 0) <= IR(7 downto 5); - end if; - end case; - --}}} - end case; - end process; + -- IR: $03,$07,$0B,$0F,$13,$17,$1B,$1F + -- $23,$27,$2B,$2F,$33,$37,$3B,$3F + -- $43,$47,$4B,$4F,$53,$57,$5B,$5F + -- $63,$67,$6B,$6F,$73,$77,$7B,$7F + -- $83,$87,$8B,$8F,$93,$97,$9B,$9F + -- $C3,$C7,$CB,$CF,$D3,$D7,$DB,$DF + -- $E3,$E7,$EB,$EF,$F3,$F7,$FB,$FF + when others => + if IR=x"6b" then -- ARR + ALU_Op<=ALU_OP_ARR; + elsif IR=x"8b" then -- ARR + ALU_Op<=ALU_OP_XAA; -- we can't use the bit operation as we don't set all flags... + elsif IR=x"0b" or IR=x"2b" then -- ANC + ALU_Op<=ALU_OP_ANC; + elsif IR=x"eb" then -- alternate SBC + ALU_Op<=ALU_OP_SBC; + elsif ALUmore='1' then + case(to_integer(unsigned(IR(7 downto 5)))) is + when 0=> + ALU_Op<=ALU_OP_OR; + when 1=> + ALU_Op<=ALU_OP_AND; + when 2=> + ALU_Op<=ALU_OP_EOR; + when 3=> + ALU_Op<=ALU_OP_ADC; + when 4=> + ALU_Op<=ALU_OP_EQ1; -- STA + when 5=> + ALU_Op<=ALU_OP_EQ2; -- LDA + when 6=> + ALU_Op<=ALU_OP_CMP; + when others=> + ALU_Op<=ALU_OP_SBC; + end case; + else + case(to_integer(unsigned(IR(7 downto 5)))) is + when 0=> + ALU_Op<=ALU_OP_ASL; + when 1=> + ALU_Op<=ALU_OP_ROL; + when 2=> + ALU_Op<=ALU_OP_LSR; + when 3=> + ALU_Op<=ALU_OP_ROR; + when 4=> + ALU_Op<=ALU_OP_BIT; + when 5=> + ALU_Op<=ALU_OP_EQ2; -- LDX + when 6=> + ALU_Op<=ALU_OP_DEC; + if IR(4 downto 2)="010" then -- $6B + ALU_Op<=ALU_OP_SAX; -- special SAX (SBX) case + end if; + when others=> + ALU_Op<=ALU_OP_INC; + end case; + end if; + end case; + end case; + end process; end; diff --git a/cores/c16/t65/T65_Pack.vhd b/cores/c16/t65/T65_Pack.vhd old mode 100644 new mode 100755 index f8d603c..f56c343 --- a/cores/c16/t65/T65_Pack.vhd +++ b/cores/c16/t65/T65_Pack.vhd @@ -1,18 +1,18 @@ -- **** -- T65(b) core. In an effort to merge and maintain bug fixes .... -- --- --- Ver 300 Bugfixes by ehenciak added --- MikeJ March 2005 --- Latest version from www.fpgaarcade.com (original www.opencores.org) +-- See list of changes in T65 top file (T65.vhd)... -- -- **** --- -- 65xx compatible microprocessor core -- --- Version : 0246 +-- FPGAARCADE SVN: $Id: T65_Pack.vhd 1234 2015-02-28 20:14:50Z wolfgang.scherr $ -- --- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org) +-- Copyright (c) 2002...2015 +-- Daniel Wallner (jesus opencores org) +-- Mike Johnson (mikej fpgaarcade com) +-- Wolfgang Scherr (WoS pin4 at> +-- Morten Leikvoll () -- -- All rights reserved -- @@ -42,76 +42,139 @@ -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- --- Please report bugs to the author, but before you do so, please +-- Please report bugs to the author(s), but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- --- The latest version of this file can be found at: --- http://www.opencores.org/cvsweb.shtml/t65/ --- -- Limitations : --- --- File history : --- +-- See in T65 top file (T65.vhd)... library IEEE; use IEEE.std_logic_1164.all; package T65_Pack is - constant Flag_C : integer := 0; - constant Flag_Z : integer := 1; - constant Flag_I : integer := 2; - constant Flag_D : integer := 3; - constant Flag_B : integer := 4; - constant Flag_1 : integer := 5; - constant Flag_V : integer := 6; - constant Flag_N : integer := 7; + constant Flag_C : integer := 0; + constant Flag_Z : integer := 1; + constant Flag_I : integer := 2; + constant Flag_D : integer := 3; + constant Flag_B : integer := 4; + constant Flag_1 : integer := 5; + constant Flag_V : integer := 6; + constant Flag_N : integer := 7; - component T65_MCode - port( - Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816 - IR : in std_logic_vector(7 downto 0); - MCycle : in std_logic_vector(2 downto 0); - P : in std_logic_vector(7 downto 0); - LCycle : out std_logic_vector(2 downto 0); - ALU_Op : out std_logic_vector(3 downto 0); - Set_BusA_To : out std_logic_vector(2 downto 0); -- DI,A,X,Y,S,P - Set_Addr_To : out std_logic_vector(1 downto 0); -- PC Adder,S,AD,BA - Write_Data : out std_logic_vector(2 downto 0); -- DL,A,X,Y,S,P,PCL,PCH - Jump : out std_logic_vector(1 downto 0); -- PC,++,DIDL,Rel - BAAdd : out std_logic_vector(1 downto 0); -- None,DB Inc,BA Add,BA Adj - BreakAtNA : out std_logic; - ADAdd : out std_logic; - AddY : out std_logic; - PCAdd : out std_logic; - Inc_S : out std_logic; - Dec_S : out std_logic; - LDA : out std_logic; - LDP : out std_logic; - LDX : out std_logic; - LDY : out std_logic; - LDS : out std_logic; - LDDI : out std_logic; - LDALU : out std_logic; - LDAD : out std_logic; - LDBAL : out std_logic; - LDBAH : out std_logic; - SaveP : out std_logic; - Write : out std_logic - ); - end component; + subtype T_Lcycle is std_logic_vector(2 downto 0); + constant Cycle_sync :T_Lcycle:="000"; + constant Cycle_1 :T_Lcycle:="001"; + constant Cycle_2 :T_Lcycle:="010"; + constant Cycle_3 :T_Lcycle:="011"; + constant Cycle_4 :T_Lcycle:="100"; + constant Cycle_5 :T_Lcycle:="101"; + constant Cycle_6 :T_Lcycle:="110"; + constant Cycle_7 :T_Lcycle:="111"; - component T65_ALU - port( - Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65C816 - Op : in std_logic_vector(3 downto 0); - BusA : in std_logic_vector(7 downto 0); - BusB : in std_logic_vector(7 downto 0); - P_In : in std_logic_vector(7 downto 0); - P_Out : out std_logic_vector(7 downto 0); - Q : out std_logic_vector(7 downto 0) - ); - end component; + function CycleNext(c:T_Lcycle) return T_Lcycle; + + type T_Set_BusA_To is + ( + Set_BusA_To_DI, + Set_BusA_To_ABC, + Set_BusA_To_X, + Set_BusA_To_Y, + Set_BusA_To_S, + Set_BusA_To_P, + Set_BusA_To_DA, + Set_BusA_To_DAO, + Set_BusA_To_DAX, + Set_BusA_To_AAX, + Set_BusA_To_DONTCARE + ); + + type T_Set_Addr_To is + ( + Set_Addr_To_PBR, + Set_Addr_To_SP, + Set_Addr_To_ZPG, + Set_Addr_To_BA + ); + + type T_Write_Data is + ( + Write_Data_DL, + Write_Data_ABC, + Write_Data_X, + Write_Data_Y, + Write_Data_S, + Write_Data_P, + Write_Data_PCL, + Write_Data_PCH, + Write_Data_AX, + Write_Data_AXB, + Write_Data_XB, + Write_Data_YB, + Write_Data_DONTCARE + ); + + type T_ALU_OP is + ( + ALU_OP_OR, --"0000" + ALU_OP_AND, --"0001" + ALU_OP_EOR, --"0010" + ALU_OP_ADC, --"0011" + ALU_OP_EQ1, --"0100" EQ1 does not change N,Z flags, EQ2/3 does. + ALU_OP_EQ2, --"0101" Not sure yet whats the difference between EQ2&3. They seem to do the same ALU op + ALU_OP_CMP, --"0110" + ALU_OP_SBC, --"0111" + ALU_OP_ASL, --"1000" + ALU_OP_ROL, --"1001" + ALU_OP_LSR, --"1010" + ALU_OP_ROR, --"1011" + ALU_OP_BIT, --"1100" +-- ALU_OP_EQ3, --"1101" + ALU_OP_DEC, --"1110" + ALU_OP_INC, --"1111" + ALU_OP_ARR, + ALU_OP_ANC, + ALU_OP_SAX, + ALU_OP_XAA +-- ALU_OP_UNDEF--"----"--may be replaced with any? + ); + + type T_t65_dbg is record + I : std_logic_vector(7 downto 0); -- instruction + A : std_logic_vector(7 downto 0); -- A reg + X : std_logic_vector(7 downto 0); -- X reg + Y : std_logic_vector(7 downto 0); -- Y reg + S : std_logic_vector(7 downto 0); -- stack pointer + P : std_logic_vector(7 downto 0); -- processor flags + end record; end; + +package body T65_Pack is + + function CycleNext(c:T_Lcycle) return T_Lcycle is + begin + case(c) is + when Cycle_sync=> + return Cycle_1; + when Cycle_1=> + return Cycle_2; + when Cycle_2=> + return Cycle_3; + when Cycle_3=> + return Cycle_4; + when Cycle_4=> + return Cycle_5; + when Cycle_5=> + return Cycle_6; + when Cycle_6=> + return Cycle_7; + when Cycle_7=> + return Cycle_sync; + when others=> + return Cycle_sync; + end case; + end CycleNext; + +end T65_Pack;