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wfjm.w11/rtl/w11a/pdp11_sequencer.vhd
Walter F.J. Mueller 3f455d5236 - interim release w11a_V0.532 (untagged) 
- re-organize modules 'human I/O' interface on Digilent boards
- add test designs for 'human I/O' interface for atlys,nexys2, and s3board
- small updates in crc8 and dcm areas
- with one exception all vhdl sources use now numeric_std
2011-11-20 12:31:43 +00:00

2279 lines
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-- $Id: pdp11_sequencer.vhd 427 2011-11-19 21:04:11Z mueller $
--
-- Copyright 2006-2011 by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>
--
-- This program is free software; you may redistribute and/or modify it under
-- the terms of the GNU General Public License as published by the Free
-- Software Foundation, either version 2, or at your option any later version.
--
-- This program is distributed in the hope that it will be useful, but
-- WITHOUT ANY WARRANTY, without even the implied warranty of MERCHANTABILITY
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for complete details.
--
------------------------------------------------------------------------------
-- Module Name: pdp11_sequencer - syn
-- Description: pdp11: CPU sequencer
--
-- Dependencies: ib_sel
-- Test bench: tb/tb_pdp11_core (implicit)
-- Target Devices: generic
-- Tool versions: xst 8.2, 9.1, 9.2, 12.1, 13.1; ghdl 0.18-0.29
--
-- Revision History:
-- Date Rev Version Comment
-- 2011-11-18 427 1.4.2 now numeric_std clean
-- 2010-10-23 335 1.4.1 use ib_sel
-- 2010-10-17 333 1.4 use ibus V2 interface
-- 2010-09-18 300 1.3.2 rename (adlm)box->(oalm)unit
-- 2010-06-20 307 1.3.1 rename cpacc to cacc in vm_cntl_type
-- 2010-06-13 305 1.3 remove CPDIN_WE, CPDOUT_WE out ports; set
-- CNTL.cpdout_we instead of CPDOUT_WE
-- 2010-06-12 304 1.2.8 signal cpuwait when spinning in s_op_wait
-- 2009-05-30 220 1.2.7 final removal of snoopers (were already commented)
-- 2009-05-09 213 1.2.6 BUGFIX: use is_dstkstack1246, stklim for mode=6
-- 2009-05-02 211 1.2.5 BUGFIX: 11/70 spl semantics again in kernel mode
-- 2009-04-26 209 1.2.4 BUGFIX: give interrupts priority over trap handling
-- 2008-12-14 177 1.2.3 BUGFIX: use is_dstkstack124, fix stklim check bug
-- 2008-12-13 176 1.2.2 BUGFIX: use is_pci in s_dstw_inc if DSTDEF='1'
-- 2008-11-30 174 1.2.1 BUGFIX: add updt_dstadsrc; prevent stale DSRC
-- 2008-08-22 161 1.2 rename ubf_ -> ibf_; use iblib
-- 2008-05-03 143 1.1.9 rename _cpursta->_cpurust; cp reset sets now
-- c_cpurust_reset; proper c_cpurust_vfail handling
-- 2008-04-27 140 1.1.8 BUGFIX: halt cpu in case of a vector fetch error
-- use cpursta to encode why cpu halts, remove cpufail
-- 2008-04-27 139 1.1.7 BUGFIX: correct bytop handling for address fetches;
-- BUGFIX: redo mtp flow; add fork_dsta fork and ddst
-- reload in s_opa_mtp_pop_w;
-- 2008-04-19 137 1.1.6 BUGFIX: fix loop state in s_rti_getpc_w
-- 2008-03-30 131 1.1.5 BUGFIX: inc/dec by 2 for byte mode -(sp),(sp)+
-- inc/dec by 2 for @(R)+ and @-(R) also for bytop's
-- 2008-03-02 121 1.1.4 remove snoopers; add waitsusp, redo WAIT handling
-- 2008-02-24 119 1.1.3 add lah,rps,wps command; revamp cp memory access
-- change WAIT logic, now also bails out on cp command
-- 2008-01-20 112 1.1.2 rename PRESET->BRESET
-- 2008-01-05 110 1.1.1 rename IB_MREQ(ena->req) SRES(sel->ack, hold->busy)
-- 2007-12-30 107 1.1 use IB_MREQ/IB_SRES interface now
-- 2007-06-14 56 1.0.1 Use slvtypes.all
-- 2007-05-12 26 1.0 Initial version
------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.slvtypes.all;
use work.iblib.all;
use work.pdp11.all;
-- ----------------------------------------------------------------------------
entity pdp11_sequencer is -- CPU sequencer
port (
CLK : in slbit; -- clock
GRESET : in slbit; -- global reset
PSW : in psw_type; -- processor status
PC : in slv16; -- program counter
IREG : in slv16; -- IREG
ID_STAT : in decode_stat_type; -- instr. decoder status
DP_STAT : in dpath_stat_type; -- data path status
CP_CNTL : in cp_cntl_type; -- console port control
VM_STAT : in vm_stat_type; -- virtual memory status port
INT_PRI : in slv3; -- interrupt priority
INT_VECT : in slv9_2; -- interrupt vector
CRESET : out slbit; -- console reset
BRESET : out slbit; -- ibus reset
MMU_MONI : out mmu_moni_type; -- mmu monitor port
DP_CNTL : out dpath_cntl_type; -- data path control
VM_CNTL : out vm_cntl_type; -- virtual memory control port
CP_STAT : out cp_stat_type; -- console port status
INT_ACK : out slbit; -- interrupt acknowledge
IB_MREQ : in ib_mreq_type; -- ibus request
IB_SRES : out ib_sres_type -- ibus response
);
end pdp11_sequencer;
architecture syn of pdp11_sequencer is
constant ibaddr_cpuerr : slv16 := slv(to_unsigned(8#177766#,16));
constant cpuerr_ibf_illhlt : integer := 7;
constant cpuerr_ibf_adderr : integer := 6;
constant cpuerr_ibf_nxm : integer := 5;
constant cpuerr_ibf_iobto : integer := 4;
constant cpuerr_ibf_ysv : integer := 3;
constant cpuerr_ibf_rsv : integer := 2;
type state_type is (
s_idle,
s_cp_regread,
s_cp_rps,
s_cp_memr_w,
s_cp_memw_w,
s_ifetch,
s_ifetch_w,
s_idecode,
s_srcr_def,
s_srcr_def_w,
s_srcr_inc,
s_srcr_inc_w,
s_srcr_dec,
s_srcr_dec1,
s_srcr_ind,
s_srcr_ind1_w,
s_srcr_ind2,
s_srcr_ind2_w,
s_dstr_def,
s_dstr_def_w,
s_dstr_inc,
s_dstr_inc_w,
s_dstr_dec,
s_dstr_dec1,
s_dstr_ind,
s_dstr_ind1_w,
s_dstr_ind2,
s_dstr_ind2_w,
s_dstw_def,
s_dstw_def_w,
s_dstw_inc,
s_dstw_inc_w,
s_dstw_incdef_w,
s_dstw_dec,
s_dstw_dec1,
s_dstw_ind,
s_dstw_ind_w,
s_dstw_def246,
s_dsta_inc,
s_dsta_incdef_w,
s_dsta_dec,
s_dsta_dec1,
s_dsta_ind,
s_dsta_ind_w,
s_op_halt,
s_op_wait,
s_op_trap,
s_op_reset,
s_op_rts,
s_op_rts_pop,
s_op_rts_pop_w,
s_op_spl,
s_op_mcc,
s_op_br,
s_op_mark,
s_op_mark1,
s_op_mark_pop,
s_op_mark_pop_w,
s_op_sob,
s_op_sob1,
s_opg_gen,
s_opg_gen_rmw_w,
s_opg_mul,
s_opg_mul1,
s_opg_div,
s_opg_div_cn,
s_opg_div_cr,
s_opg_div_sq,
s_opg_div_sr,
s_opg_div_zero,
s_opg_ash,
s_opg_ash_cn,
s_opg_ashc,
s_opg_ashc_cn,
s_opg_ashc_wl,
s_opa_jsr,
s_opa_jsr1,
s_opa_jsr_push,
s_opa_jsr_push_w,
s_opa_jsr2,
s_opa_jmp,
s_opa_mtp,
s_opa_mtp_pop_w,
s_opa_mtp_reg,
s_opa_mtp_mem,
s_opa_mtp_mem_w,
s_opa_mfp_reg,
s_opa_mfp_mem,
s_opa_mfp_mem_w,
s_opa_mfp_dec,
s_opa_mfp_push,
s_opa_mfp_push_w,
s_trap_4,
s_trap_10,
s_trap_disp,
s_int_ext,
s_int_getpc,
s_int_getpc_w,
s_int_getps,
s_int_getps_w,
s_int_getsp,
s_int_decsp,
s_int_pushps,
s_int_pushps_w,
s_int_pushpc,
s_int_pushpc_w,
s_rti_getpc,
s_rti_getpc_w,
s_rti_getps,
s_rti_getps_w,
s_rti_newpc,
s_vmerr,
s_cpufail
);
signal R_STATE : state_type := s_idle; -- state register
signal N_STATE : state_type := s_idle;
signal R_STATUS : cpustat_type := cpustat_init;
signal N_STATUS : cpustat_type := cpustat_init;
signal R_CPUERR : cpuerr_type := cpuerr_init;
signal N_CPUERR : cpuerr_type := cpuerr_init;
signal R_IDSTAT : decode_stat_type := decode_stat_init;
signal N_IDSTAT : decode_stat_type := decode_stat_init;
signal R_VMSTAT : vm_stat_type := vm_stat_init;
signal IBSEL_CPUERR : slbit := '0';
begin
SEL : ib_sel
generic map (
IB_ADDR => ibaddr_cpuerr)
port map (
CLK => CLK,
IB_MREQ => IB_MREQ,
SEL => IBSEL_CPUERR
);
proc_ibres : process (IBSEL_CPUERR, IB_MREQ, R_CPUERR)
variable idout : slv16 := (others=>'0');
begin
idout := (others=>'0');
if IBSEL_CPUERR = '1' then
idout(cpuerr_ibf_illhlt) := R_CPUERR.illhlt;
idout(cpuerr_ibf_adderr) := R_CPUERR.adderr;
idout(cpuerr_ibf_nxm) := R_CPUERR.nxm;
idout(cpuerr_ibf_iobto) := R_CPUERR.iobto;
idout(cpuerr_ibf_ysv) := R_CPUERR.ysv;
idout(cpuerr_ibf_rsv) := R_CPUERR.rsv;
end if;
IB_SRES.dout <= idout;
IB_SRES.ack <= IBSEL_CPUERR and (IB_MREQ.re or IB_MREQ.we); -- ack all
IB_SRES.busy <= '0';
end process proc_ibres;
proc_status: process (CLK)
begin
if rising_edge(CLK) then
if GRESET = '1' then
R_STATUS <= cpustat_init;
R_CPUERR <= cpuerr_init;
R_IDSTAT <= decode_stat_init;
R_VMSTAT <= vm_stat_init;
else
R_STATUS <= N_STATUS;
R_CPUERR <= N_CPUERR;
R_IDSTAT <= N_IDSTAT;
R_VMSTAT <= VM_STAT;
end if;
end if;
end process proc_status;
proc_state: process (CLK)
begin
if rising_edge(CLK) then
if GRESET = '1' then
R_STATE <= s_idle;
else
R_STATE <= N_STATE;
end if;
end if;
end process proc_state;
proc_next: process (R_STATE, R_STATUS, PSW, PC, CP_CNTL,
ID_STAT, R_IDSTAT, IREG, VM_STAT, DP_STAT,
R_CPUERR, R_VMSTAT, IB_MREQ, IBSEL_CPUERR,
INT_PRI, INT_VECT)
variable nstate : state_type;
variable nstatus : cpustat_type := cpustat_init;
variable ncpuerr : cpuerr_type := cpuerr_init;
variable ncreset : slbit := '0';
variable nbreset : slbit := '0';
variable nintack : slbit := '0';
variable ndpcntl : dpath_cntl_type := dpath_cntl_init;
variable nvmcntl : vm_cntl_type := vm_cntl_init;
variable nidstat : decode_stat_type := decode_stat_init;
variable nmmumoni : mmu_moni_type := mmu_moni_init;
variable imemok : boolean;
variable bytop : slbit := '0'; -- local bytop access flag
variable macc : slbit := '0'; -- local modify access flag
variable lvector : slv9_2 := (others=>'0'); -- local trap/interrupt vector
variable brcode : slv4 := (others=>'0'); -- reduced br opcode (15,10-8)
variable brcond : slbit := '0'; -- br condition value
variable is_kmode : slbit := '0'; -- cmode is kernel mode
variable is_dstkstack1246 : slbit := '0'; -- dest is k-stack & mode= 1,2,4,6
variable int_pending : slbit := '0'; -- an interrupt is pending
alias SRCMOD : slv2 is IREG(11 downto 10); -- src register mode high
alias SRCDEF : slbit is IREG(9); -- src register mode defered
alias SRCREG : slv3 is IREG(8 downto 6); -- src register number
alias DSTMODF : slv3 is IREG(5 downto 3); -- dst register full mode
alias DSTMOD : slv2 is IREG(5 downto 4); -- dst register mode high
alias DSTDEF : slbit is IREG(3); -- dst register mode defered
alias DSTREG : slv3 is IREG(2 downto 0); -- dst register number
procedure do_memread_i(nstate : inout state_type;
ndpcntl : inout dpath_cntl_type;
nvmcntl : inout vm_cntl_type;
wstate : in state_type) is
begin
ndpcntl.vmaddr_sel := c_dpath_vmaddr_pc; -- VA = PC
nvmcntl.dspace := '0';
nvmcntl.req := '1';
ndpcntl.gpr_pcinc := '1'; -- (pc)++
nstate := wstate;
end procedure do_memread_i;
procedure do_memread_d(nstate : inout state_type;
nvmcntl : inout vm_cntl_type;
wstate : in state_type;
bytop : in slbit := '0';
macc : in slbit := '0';
is_pci : in slbit := '0') is
begin
nvmcntl.dspace := not is_pci; -- ispace if pc immediate modes
-- bytop := R_IDSTAT.is_bytop and not is_addr;
nvmcntl.bytop := bytop;
nvmcntl.macc := macc;
nvmcntl.req := '1';
nstate := wstate;
end procedure do_memread_d;
procedure do_memread_srcinc(nstate : inout state_type;
ndpcntl : inout dpath_cntl_type;
nvmcntl : inout vm_cntl_type;
wstate : in state_type;
nmmumoni : inout mmu_moni_type;
updt_sp : in slbit := '0') is
begin
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_const := "000000010"; -- OUNIT const=2
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- update DSRC
if updt_sp = '1' then
nmmumoni.regmod := '1';
nmmumoni.isdec := '0';
ndpcntl.gpr_adst := c_gpr_sp; -- update SP too
ndpcntl.gpr_we := '1';
end if;
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
nvmcntl.dspace := '1';
nvmcntl.req := '1';
nstate := wstate;
end procedure do_memread_srcinc;
procedure do_memwrite(nstate : inout state_type;
nvmcntl : inout vm_cntl_type;
wstate : in state_type;
macc : in slbit :='0') is
begin
nvmcntl.dspace := '1';
nvmcntl.bytop := R_IDSTAT.is_bytop;
nvmcntl.wacc := '1';
nvmcntl.macc := macc;
nvmcntl.req := '1';
nstate := wstate;
end procedure do_memwrite;
procedure do_memcheck(nstate : inout state_type;
nstatus : inout cpustat_type;
mok : out boolean) is
begin
mok := false;
if VM_STAT.ack = '1' then
mok := true;
nstatus.trap_mmu := VM_STAT.trap_mmu;
if R_CPUERR.ysv = '0' then -- ysv trap when cpuerr not yet set
nstatus.trap_ysv := VM_STAT.trap_ysv;
end if;
elsif VM_STAT.err='1' or VM_STAT.fail='1' then
nstate := s_vmerr;
end if;
end procedure do_memcheck;
procedure do_const_opsize(ndpcntl : inout dpath_cntl_type;
bytop : in slbit;
isdef : in slbit;
regnum : in slv3) is
begin
if bytop='0' or isdef='1' or
regnum=c_gpr_pc or regnum=c_gpr_sp then
ndpcntl.ounit_const := "000000010";
else
ndpcntl.ounit_const := "000000001";
end if;
end procedure do_const_opsize;
procedure do_fork_dstr(nstate : inout state_type;
idstat : in decode_stat_type) is
begin
case idstat.fork_dstr is
when c_fork_dstr_def => nstate := s_dstr_def;
when c_fork_dstr_inc => nstate := s_dstr_inc;
when c_fork_dstr_dec => nstate := s_dstr_dec;
when c_fork_dstr_ind => nstate := s_dstr_ind;
when others => nstate := s_cpufail;
end case;
end procedure do_fork_dstr;
procedure do_fork_opg(nstate : inout state_type;
idstat : in decode_stat_type) is
begin
case idstat.fork_opg is
when c_fork_opg_gen => nstate := s_opg_gen;
when c_fork_opg_wdef => nstate := s_dstw_def;
when c_fork_opg_winc => nstate := s_dstw_inc;
when c_fork_opg_wdec => nstate := s_dstw_dec;
when c_fork_opg_wind => nstate := s_dstw_ind;
when c_fork_opg_mul => nstate := s_opg_mul;
when c_fork_opg_div => nstate := s_opg_div;
when c_fork_opg_ash => nstate := s_opg_ash;
when c_fork_opg_ashc => nstate := s_opg_ashc;
when others => nstate := s_cpufail;
end case;
end procedure do_fork_opg;
procedure do_fork_opa(nstate : inout state_type;
idstat : in decode_stat_type) is
begin
case idstat.fork_opa is
when c_fork_opa_jmp => nstate := s_opa_jmp;
when c_fork_opa_jsr => nstate := s_opa_jsr;
when c_fork_opa_mtp => nstate := s_opa_mtp_mem;
when c_fork_opa_mfp_reg => nstate := s_opa_mfp_reg;
when c_fork_opa_mfp_mem => nstate := s_opa_mfp_mem;
when others => nstate := s_cpufail;
end case;
end procedure do_fork_opa;
procedure do_fork_next(nstate : inout state_type;
nstatus : inout cpustat_type;
nmmumoni : inout mmu_moni_type) is
begin
nmmumoni.idone := '1';
if unsigned(INT_PRI) > unsigned(PSW.pri) then
nstate := s_idle;
elsif R_STATUS.trap_mmu='1' or nstatus.trap_mmu='1' or
R_STATUS.trap_ysv='1' or nstatus.trap_ysv='1' or
PSW.tflag='1' then
nstate := s_trap_disp;
elsif R_STATUS.cpugo='1' and not R_STATUS.cmdbusy='1' then
nstate := s_ifetch;
else
nstate := s_idle;
end if;
end procedure do_fork_next;
procedure do_fork_next_pref(nstate : inout state_type;
nstatus : inout cpustat_type;
ndpcntl : inout dpath_cntl_type;
nvmcntl : inout vm_cntl_type;
nmmumoni : inout mmu_moni_type) is
begin
nmmumoni.idone := '1';
if unsigned(INT_PRI) > unsigned(PSW.pri) then
nstate := s_idle;
elsif R_STATUS.trap_mmu='1' or nstatus.trap_mmu='1' or
R_STATUS.trap_ysv='1' or nstatus.trap_ysv='1' or
PSW.tflag='1' then
nstate := s_trap_disp;
elsif R_STATUS.cpugo='1' and not R_STATUS.cmdbusy='1' then
nvmcntl.req := '1';
ndpcntl.gpr_pcinc := '1';
nmmumoni.istart := '1';
nstate := s_ifetch_w;
else
nstate := s_idle;
end if;
end procedure do_fork_next_pref;
procedure do_start_int(nstate : inout state_type;
ndpcntl : inout dpath_cntl_type;
vector : in slv9_2) is
begin
ndpcntl.dtmp_sel := c_dpath_dtmp_psw; -- DTMP = PSW
ndpcntl.dtmp_we := '1';
ndpcntl.ounit_azero := '1'; -- OUNIT A = 0
ndpcntl.ounit_const := vector & "00"; -- vector
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const(vector)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- DSRC = vector
nstate := s_int_getpc;
end procedure do_start_int;
begin
nstate := R_STATE;
nstatus := R_STATUS;
ncpuerr := R_CPUERR;
nstatus.cpuwait := '0'; -- wait flag 0 unless set in s_op_wait
ncreset := '0';
nbreset := '0';
nintack := '0';
nidstat := R_IDSTAT;
if IBSEL_CPUERR='1' and IB_MREQ.we='1' then -- write to CPUERR clears it !
ncpuerr := cpuerr_init;
end if;
int_pending := '0';
if unsigned(INT_PRI) > unsigned(PSW.pri) then
int_pending := '1';
end if;
imemok := false;
nmmumoni := mmu_moni_init;
nmmumoni.pc := PC;
macc := '0';
bytop := '0';
brcode := IREG(15) & IREG(10 downto 8);
brcond := '1';
is_kmode := '0';
is_dstkstack1246 := '0';
if PSW.cmode = c_psw_kmode then
is_kmode := '1';
if DSTREG = c_gpr_sp and
(DSTMODF="001" or DSTMODF="010" or
DSTMODF="100" or DSTMODF="110") then
is_dstkstack1246 := '1';
end if;
end if;
lvector := (others=>'0');
nvmcntl := vm_cntl_init;
nvmcntl.dspace := '1'; -- DEFAULT
nvmcntl.mode := PSW.cmode; -- DEFAULT
nvmcntl.intrsv := R_STATUS.do_intrsv; -- DEFAULT
ndpcntl := dpath_cntl_init;
ndpcntl.gpr_asrc := SRCREG; -- DEFAULT
ndpcntl.gpr_adst := DSTREG; -- DEFAULT
ndpcntl.gpr_mode := PSW.cmode; -- DEFAULT
ndpcntl.gpr_rset := PSW.rset; -- DEFAULT
ndpcntl.gpr_we := '0'; -- DEFAULT
ndpcntl.gpr_bytop := '0'; -- DEFAULT
ndpcntl.gpr_pcinc := '0'; -- DEFAULT
ndpcntl.psr_ccwe := '0'; -- DEFAULT
ndpcntl.psr_we := '0'; -- DEFAULT
ndpcntl.psr_func := "000"; -- DEFAULT
ndpcntl.dsrc_sel := c_dpath_dsrc_src;
ndpcntl.dsrc_we := '0';
ndpcntl.ddst_sel := c_dpath_ddst_dst;
ndpcntl.ddst_we := '0';
ndpcntl.dtmp_sel := c_dpath_dtmp_dsrc;
ndpcntl.dtmp_we := '0';
ndpcntl.ounit_asel := c_ounit_asel_ddst;
ndpcntl.ounit_azero := '0'; -- DEFAULT
ndpcntl.ounit_const := (others=>'0'); -- DEFAULT
ndpcntl.ounit_bsel := c_ounit_bsel_const;
ndpcntl.ounit_opsub := '0'; -- DEFAULT
ndpcntl.aunit_srcmod := R_IDSTAT.aunit_srcmod; -- STATIC
ndpcntl.aunit_dstmod := R_IDSTAT.aunit_dstmod; -- STATIC
ndpcntl.aunit_cimod := R_IDSTAT.aunit_cimod; -- STATIC
ndpcntl.aunit_cc1op := R_IDSTAT.aunit_cc1op; -- STATIC
ndpcntl.aunit_ccmode := R_IDSTAT.aunit_ccmode; -- STATIC
ndpcntl.aunit_bytop := R_IDSTAT.is_bytop; -- STATIC
ndpcntl.lunit_func := R_IDSTAT.lunit_func; -- STATIC
ndpcntl.lunit_bytop := R_IDSTAT.is_bytop; -- STATIC
ndpcntl.munit_func := R_IDSTAT.munit_func; -- STATIC
ndpcntl.ireg_we := '0';
ndpcntl.cres_sel := R_IDSTAT.res_sel; -- DEFAULT
ndpcntl.dres_sel := c_dpath_res_ounit;
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc;
if CP_CNTL.req='1' and R_STATUS.cmdbusy='0' then
nstatus.cmdbusy := '1';
nstatus.cpfunc := CP_CNTL.func;
nstatus.cprnum := CP_CNTL.rnum;
end if;
if R_STATUS.cmdack = '1' then
nstatus.cmdack := '0';
nstatus.cmderr := '0';
nstatus.cmdmerr := '0';
end if;
case R_STATE is
-- idle and command port states ---------------------------------------------
-- Note: s_idle was entered from suspended WAIT when waitsusp='1'
-- --> all exits must check this and either return to s_op_wait
-- or abort the WAIT and set waitsusp='0'
when s_idle =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST (do mux early)
nstatus.cpustep := '0';
if R_STATUS.cmdbusy = '1' then
case R_STATUS.cpfunc is
when c_cpfunc_noop => -- noop : no operation --------
nstatus.cmdack := '1';
nstate := s_idle;
when c_cpfunc_sta => -- sta : cpu start -----------
ncreset := '1';
nstatus.cmdack := '1';
nstatus.cpugo := '1';
nstatus.cpuhalt := '0';
nstatus.cpurust := c_cpurust_runs;
nstatus.waitsusp := '0';
nstate := s_idle;
when c_cpfunc_sto => -- sto : cpu stop ------------
nstatus.cmdack := '1';
nstatus.cpugo := '0';
nstatus.cpurust := c_cpurust_stop;
nstatus.waitsusp := '0';
nstate := s_idle;
when c_cpfunc_cont => -- cont : cpu continue --------
nstatus.cmdack := '1';
nstatus.cpugo := '1';
nstatus.cpuhalt := '0';
nstatus.cpurust := c_cpurust_runs;
nstatus.waitsusp := '0';
nstate := s_idle;
when c_cpfunc_step => -- step : cpu step ------------
nstatus.cmdack := '1';
nstatus.cpustep := '1';
nstatus.cpuhalt := '0';
nstatus.cpurust := c_cpurust_step;
nstatus.waitsusp := '0';
if int_pending = '1' then
nintack := '1';
nstatus.intvect := INT_VECT;
nstate := s_int_ext;
else
nstate := s_ifetch;
end if;
when c_cpfunc_rst => -- rst : cpu reset (soft) ----
ncreset := '1';
nstatus.cmdack := '1';
nstatus.cpugo := '0';
nstatus.cpuhalt := '0';
nstatus.cpurust := c_cpurust_reset;
nstatus.waitsusp := '0';
nstate := s_idle;
when c_cpfunc_rreg => -- rreg : read register ------
ndpcntl.gpr_adst := R_STATUS.cprnum;
ndpcntl.ddst_sel := c_dpath_ddst_dst;
ndpcntl.ddst_we := '1';
nstate := s_cp_regread;
when c_cpfunc_wreg => -- wreg : write register -----
ndpcntl.dres_sel := c_dpath_res_cpdin; -- DRES = CPDIN
ndpcntl.gpr_adst := R_STATUS.cprnum;
ndpcntl.gpr_we := '1';
nstatus.cmdack := '1';
nstate := s_idle;
when c_cpfunc_rpsw => -- rpsw : read psw -----------
ndpcntl.dtmp_sel := c_dpath_dtmp_psw; -- DTMP = PSW
ndpcntl.dtmp_we := '1';
nstate := s_cp_rps;
when c_cpfunc_wpsw => -- wpsw : write psw ----------
ndpcntl.dres_sel := c_dpath_res_cpdin; -- DRES = CPDIN
ndpcntl.psr_func := c_psr_func_wall; -- write all fields
ndpcntl.psr_we := '1'; -- load new PS
nstatus.cmdack := '1';
nstate := s_idle;
when c_cpfunc_rmem => -- rmem : read memory --------
nvmcntl.cacc := '1';
nvmcntl.req := '1';
nstate := s_cp_memr_w;
when c_cpfunc_wmem => -- wmem : write memory -------
ndpcntl.dres_sel := c_dpath_res_cpdin; -- DRES = CPDIN
nvmcntl.wacc := '1'; -- write mem
nvmcntl.cacc := '1';
nvmcntl.req := '1';
nstate := s_cp_memw_w;
when others =>
nstatus.cmdack := '1';
nstatus.cmderr := '1';
nstate := s_idle;
end case;
elsif R_STATUS.waitsusp = '1' then
nstatus.waitsusp := '0';
nstate := s_op_wait;
elsif R_STATUS.cpugo = '1' then
if int_pending = '1' then
nintack := '1';
nstatus.intvect := INT_VECT;
nstate := s_int_ext;
else
nstate := s_ifetch;
end if;
end if;
when s_cp_regread =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A = DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
nstatus.cmdack := '1';
nstate := s_idle;
when s_cp_rps =>
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A = DTMP
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
nstatus.cmdack := '1';
nstate := s_idle;
when s_cp_memr_w =>
nstate := s_cp_memr_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
if (VM_STAT.ack or VM_STAT.err or VM_STAT.fail)='1' then
nstatus.cmdack := '1';
nstatus.trap_ysv := '0'; -- suppress traps on console
nstatus.trap_mmu := '0';
nstatus.cmdmerr := VM_STAT.err or VM_STAT.fail;
nstate := s_idle;
end if;
when s_cp_memw_w =>
nstate := s_cp_memw_w;
if (VM_STAT.ack or VM_STAT.err or VM_STAT.fail)='1' then
nstatus.cmdack := '1';
nstatus.trap_ysv := '0'; -- suppress traps on console
nstatus.trap_mmu := '0';
nstatus.cmdmerr := VM_STAT.err or VM_STAT.fail;
nstate := s_idle;
end if;
-- instruction fetch and decode ---------------------------------------------
when s_ifetch =>
nmmumoni.istart := '1'; -- do here; memread_i inc PC !
do_memread_i(nstate, ndpcntl, nvmcntl, s_ifetch_w);
when s_ifetch_w =>
nstate := s_ifetch_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ireg_we := '1';
nstate := s_idecode;
end if;
when s_idecode =>
nidstat := ID_STAT; -- register decode status
if ID_STAT.force_srcsp = '1' then
ndpcntl.gpr_asrc := c_gpr_sp;
end if;
ndpcntl.dsrc_sel := c_dpath_dsrc_src;
ndpcntl.dsrc_we := '1';
ndpcntl.ddst_sel := c_dpath_ddst_dst;
ndpcntl.ddst_we := '1';
nvmcntl.dspace := '0';
ndpcntl.vmaddr_sel := c_dpath_vmaddr_pc; -- VA = PC
if ID_STAT.do_pref_dec='1' and PSW.tflag='0' and int_pending='0' and
R_STATUS.cpugo='1' and not R_STATUS.cmdbusy='1'
then
nvmcntl.req := '1';
ndpcntl.gpr_pcinc := '1'; -- (pc)++
nmmumoni.istart := '1';
nstatus.prefdone := '1';
end if;
if ID_STAT.do_fork_op = '1' then
case ID_STAT.fork_op is
when c_fork_op_halt => nstate := s_op_halt;
when c_fork_op_wait => nstate := s_op_wait;
when c_fork_op_rtti => nstate := s_rti_getpc;
when c_fork_op_trap => nstate := s_op_trap;
when c_fork_op_reset=> nstate := s_op_reset;
when c_fork_op_rts => nstate := s_op_rts;
when c_fork_op_spl => nstate := s_op_spl;
when c_fork_op_mcc => nstate := s_op_mcc;
when c_fork_op_br => nstate := s_op_br;
when c_fork_op_mark => nstate := s_op_mark;
when c_fork_op_sob => nstate := s_op_sob;
when c_fork_op_mtp => nstate := s_opa_mtp;
when others => nstate := s_cpufail;
end case;
elsif ID_STAT.do_fork_srcr = '1' then
case ID_STAT.fork_srcr is
when c_fork_srcr_def => nstate := s_srcr_def;
when c_fork_srcr_inc => nstate := s_srcr_inc;
when c_fork_srcr_dec => nstate := s_srcr_dec;
when c_fork_srcr_ind => nstate := s_srcr_ind;
when others => nstate := s_cpufail;
end case;
elsif ID_STAT.do_fork_dstr = '1' then
do_fork_dstr(nstate, ID_STAT);
elsif ID_STAT.do_fork_dsta = '1' then
case ID_STAT.fork_dsta is -- 2nd dsta fork in s_opa_mtp_pop_w
when c_fork_dsta_def => do_fork_opa(nstate, ID_STAT);
when c_fork_dsta_inc => nstate := s_dsta_inc;
when c_fork_dsta_dec => nstate := s_dsta_dec;
when c_fork_dsta_ind => nstate := s_dsta_ind;
when others => nstate := s_cpufail;
end case;
elsif ID_STAT.do_fork_opg = '1' then
do_fork_opg(nstate, ID_STAT);
elsif ID_STAT.is_res = '1' then
nstate := s_trap_10; -- do trap 10;
else
nstate := s_cpufail; -- catch mistakes here...
end if;
-- source read states -------------------------------------------------------
-- flows:
-- 1 (r) s_srcr_def req (r)
-- s_srcr_def_w get (r)
-- -> do_fork_dstr or do_fork_opg
--
-- 2 (r)+ s_srcr_inc req (r); r+=s
-- s_srcr_inc_w get (r)
-- -> do_fork_dstr or do_fork_opg
--
-- 3 @(r)+ s_srcr_inc req (r); r+=s
-- s_srcr_inc_w get (r)
-- s_srcr_def req @(r)
-- s_srcr_def_w get @(r)
-- -> do_fork_dstr or do_fork_opg
--
-- 4 -(r) s_srcr_dec r-=s
-- s_srcr_dec1 req (r)
-- s_srcr_inc_w get (r)
-- -> do_fork_dstr or do_fork_opg
--
-- 5 @-(r) s_srcr_dec r-=s
-- s_srcr_dec1 req (r)
-- s_srcr_inc_w get (r)
-- s_srcr_def req @(r)
-- s_srcr_def_w get @(r)
-- -> do_fork_dstr or do_fork_opg
--
-- 6 n(r) s_srcr_ind req n
-- s_srcr_ind1_w get n; ea=r+n
-- s_srcr_ind2 req n(r)
-- s_srcr_ind2_w get n(r)
-- -> do_fork_dstr or do_fork_opg
--
-- 7 @n(r) s_srcr_ind req n
-- s_srcr_ind1_w get n; ea=r+n
-- s_srcr_ind2 req n(r)
-- s_srcr_ind2_w get n(r)
-- s_srcr_def req @n(r)
-- s_srcr_def_w get @n(r)
-- -> do_fork_dstr or do_fork_opg
when s_srcr_def =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
do_memread_d(nstate, nvmcntl, s_srcr_def_w,
bytop=>R_IDSTAT.is_bytop,
is_pci=>R_IDSTAT.is_srcpcmode1);
when s_srcr_def_w =>
nstate := s_srcr_def_w;
do_memcheck(nstate, nstatus, imemok);
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
if imemok then
ndpcntl.dsrc_we := '1'; -- update DSRC
if R_IDSTAT.do_fork_dstr = '1' then
do_fork_dstr(nstate, R_IDSTAT);
else
do_fork_opg(nstate, R_IDSTAT);
end if;
end if;
when s_srcr_inc =>
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, SRCDEF, SRCREG);
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := SRCREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '0';
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES (for if)
if DSTREG = SRCREG then -- prevent stale DDST copy
ndpcntl.ddst_we := '1'; -- update DDST
end if;
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
bytop := R_IDSTAT.is_bytop and not SRCDEF;
do_memread_d(nstate, nvmcntl, s_srcr_inc_w,
bytop=>bytop, is_pci=>R_IDSTAT.is_srcpc);
when s_srcr_inc_w =>
nstate := s_srcr_inc_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.dsrc_we := '1'; -- update DSRC
if SRCDEF = '1' then
nstate := s_srcr_def;
else
if R_IDSTAT.do_fork_dstr = '1' then
do_fork_dstr(nstate, R_IDSTAT);
else
do_fork_opg(nstate, R_IDSTAT);
end if;
end if;
end if;
when s_srcr_dec =>
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, SRCDEF, SRCREG);
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.gpr_adst := SRCREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '1';
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES (for if)
if DSTREG = SRCREG then -- prevent stale DDST copy
ndpcntl.ddst_we := '1'; -- update DDST
end if;
nstate := s_srcr_dec1;
when s_srcr_dec1 =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
bytop := R_IDSTAT.is_bytop and not SRCDEF;
do_memread_d(nstate, nvmcntl, s_srcr_inc_w, bytop=>bytop);
when s_srcr_ind =>
do_memread_i(nstate, ndpcntl, nvmcntl, s_srcr_ind1_w);
when s_srcr_ind1_w =>
nstate := s_srcr_ind1_w;
if R_IDSTAT.is_srcpc = '0' then
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A = DSRC
else
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC (for nn(pc))
end if;
ndpcntl.ounit_bsel := c_ounit_bsel_vmdout; -- OUNIT B = VMDOUT
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.ddst_sel := c_dpath_ddst_dst; -- DDST = R(DST)
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.ddst_we := '1'; -- update DDST (to reload PC)
nstate := s_srcr_ind2;
end if;
when s_srcr_ind2 =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
bytop := R_IDSTAT.is_bytop and not SRCDEF;
do_memread_d(nstate, nvmcntl, s_srcr_ind2_w, bytop=>bytop);
when s_srcr_ind2_w =>
nstate := s_srcr_ind2_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.dsrc_we := '1'; -- update DSRC
if SRCDEF = '1' then
nstate := s_srcr_def;
else
if R_IDSTAT.do_fork_dstr = '1' then
do_fork_dstr(nstate, R_IDSTAT);
else
do_fork_opg(nstate, R_IDSTAT);
end if;
end if;
end if;
-- destination read states --------------------------------------------------
-- flows:
-- 1 (r) s_dstr_def req (r) (rmw if rmw op)
-- s_dstr_def_w get (r)
-- -> do_fork_opg
--
-- 2 (r)+ s_dstr_inc req (r); r+=s (rmw if rmw op)
-- s_dstr_inc_w get (r)
-- -> do_fork_opg
--
-- 3 @(r)+ s_dstr_inc req (r); r+=s
-- s_dstr_inc_w get (r)
-- s_dstr_def req @(r) (rmw if rmw op)
-- s_dstr_def_w get @(r)
-- -> do_fork_opg
--
-- 4 -(r) s_dstr_dec r-=s
-- s_dstr_dec1 req (r) (rmw if rmw op)
-- s_dstr_inc_w get (r)
-- -> do_fork_opg
--
-- 5 @-(r) s_dstr_dec r-=s
-- s_dstr_dec1 req (r)
-- s_dstr_inc_w get (r)
-- s_dstr_def req @(r) (rmw if rmw op)
-- s_dstr_def_w get @(r)
-- -> do_fork_opg
--
-- 6 n(r) s_dstr_ind req n
-- s_dstr_ind1_w get n; ea=r+n
-- s_dstr_ind2 req n(r) (rmw if rmw op)
-- s_dstr_ind2_w get n(r)
-- -> do_fork_opg
--
-- 7 @n(r) s_dstr_ind req n
-- s_dstr_ind1_w get n; ea=r+n
-- s_dstr_ind2 req n(r)
-- s_dstr_ind2_w get n(r)
-- s_dstr_def req @n(r) (rmw if rmw op)
-- s_dstr_def_w get @n(r)
-- -> do_fork_opg
when s_dstr_def =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
do_memread_d(nstate, nvmcntl, s_dstr_def_w,
bytop=>R_IDSTAT.is_bytop, macc=>R_IDSTAT.is_rmwop);
when s_dstr_def_w =>
nstate := s_dstr_def_w;
do_memcheck(nstate, nstatus, imemok);
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
do_fork_opg(nstate, R_IDSTAT);
end if;
when s_dstr_inc =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, DSTDEF, DSTREG);
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := DSTREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '0';
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
macc := R_IDSTAT.is_rmwop and not DSTDEF;
bytop := R_IDSTAT.is_bytop and not DSTDEF;
do_memread_d(nstate, nvmcntl, s_dstr_inc_w,
bytop=>bytop, macc=>macc, is_pci=>R_IDSTAT.is_dstpc);
when s_dstr_inc_w =>
nstate := s_dstr_inc_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
if DSTDEF = '1' then
nstate := s_dstr_def;
else
do_fork_opg(nstate, R_IDSTAT);
end if;
end if;
when s_dstr_dec =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, DSTDEF, DSTREG);
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
ndpcntl.ddst_we := '1'; -- update DDST
ndpcntl.gpr_adst := DSTREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '1';
nstate := s_dstr_dec1;
when s_dstr_dec1 =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
macc := R_IDSTAT.is_rmwop and not DSTDEF;
bytop := R_IDSTAT.is_bytop and not DSTDEF;
do_memread_d(nstate, nvmcntl, s_dstr_inc_w,
bytop=>bytop, macc=>macc);
when s_dstr_ind =>
do_memread_i(nstate, ndpcntl, nvmcntl, s_dstr_ind1_w);
when s_dstr_ind1_w =>
nstate := s_dstr_ind1_w;
if R_IDSTAT.is_dstpc = '0' then
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A = DDST
else
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC (for nn(pc))
end if;
ndpcntl.ounit_bsel := c_ounit_bsel_vmdout;-- OUNIT B = VMDOUT
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
nstate := s_dstr_ind2;
end if;
when s_dstr_ind2 =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
macc := R_IDSTAT.is_rmwop and not DSTDEF;
bytop := R_IDSTAT.is_bytop and not DSTDEF;
do_memread_d(nstate, nvmcntl, s_dstr_ind2_w,
bytop=>bytop, macc=>macc);
when s_dstr_ind2_w =>
nstate := s_dstr_ind2_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
if DSTDEF = '1' then
nstate := s_dstr_def;
else
do_fork_opg(nstate, R_IDSTAT);
end if;
end if;
-- destination write states -------------------------------------------------
-- flows:
-- 1 (r) s_dstw_def wreq (r) check kstack
-- s_dstw_def_w ack (r)
-- -> do_fork_next
--
-- 2 (r)+ s_dstw_inc wreq (r) check kstack
-- s_dstw_inc_w ack (r); r+=s
-- -> do_fork_next
--
-- 3 @(r)+ s_dstw_inc rreq (r); r+=s
-- s_dstw_incdef_w get (r)
-- s_dstw_def246 wreq @(r)
-- s_dstw_def_w ack @(r)
-- -> do_fork_next
--
-- 4 -(r) s_dstw_dec r-=s
-- s_dstw_dec1 wreq (r) check kstack
-- s_dstw_def_w ack (r)
-- -> do_fork_next
--
-- 5 @-(r) s_dstw_dec r-=s
-- s_dstw_dec1 rreq (r)
-- s_dstw_incdef_w get (r)
-- s_dstw_def246 wreq @(r)
-- s_dstw_def_w ack @(r)
-- -> do_fork_next
--
-- 6 n(r) s_dstw_ind rreq n
-- s_dstw_ind_w get n; ea=r+n
-- s_dstw_dec1 wreq n(r) check kstack
-- s_dstw_def_w ack n(r)
-- -> do_fork_next
--
-- 7 @n(r) s_dstw_ind rreq n
-- s_dstw_ind_w get n; ea=r+n
-- s_dstw_dec1 rreq n(r)
-- s_dstw_incdef_w get n(r)
-- s_dstw_def246 wreq @n(r)
-- s_dstw_def_w ack @n(r)
-- -> do_fork_next
when s_dstw_def =>
ndpcntl.psr_ccwe := '1';
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
nvmcntl.kstack := is_dstkstack1246;
do_memwrite(nstate, nvmcntl, s_dstw_def_w);
when s_dstw_def_w =>
nstate := s_dstw_def_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_dstw_inc =>
ndpcntl.psr_ccwe := '1';
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST (for else)
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, DSTDEF, DSTREG); --(...)
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (for else)
if DSTDEF = '0' then
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
nvmcntl.kstack := is_dstkstack1246;
do_memwrite(nstate, nvmcntl, s_dstw_inc_w);
nstatus.do_gprwe := '1';
else
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := DSTREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '0';
do_memread_d(nstate, nvmcntl, s_dstw_incdef_w,
is_pci=>R_IDSTAT.is_dstpc);
end if;
when s_dstw_inc_w =>
nstate := s_dstw_inc_w;
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, DSTDEF, DSTREG);
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := DSTREG;
if R_STATUS.do_gprwe = '1' then
nmmumoni.regmod := '1';
nmmumoni.isdec := '0';
nmmumoni.trace_prev := '1'; -- ssr freeze of prev state
ndpcntl.gpr_we := '1'; -- update DST reg
end if;
nstatus.do_gprwe := '0';
do_memcheck(nstate, nstatus, imemok);
if imemok then
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_dstw_incdef_w =>
nstate := s_dstw_incdef_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
nstate := s_dstw_def246;
end if;
when s_dstw_dec =>
ndpcntl.psr_ccwe := '1';
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
do_const_opsize(ndpcntl, R_IDSTAT.is_bytop, DSTDEF, DSTREG);
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
ndpcntl.ddst_we := '1'; -- update DDST
ndpcntl.gpr_adst := DSTREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '1';
nstate := s_dstw_dec1;
when s_dstw_dec1 =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = from idec (for if)
if DSTDEF = '0' then
nvmcntl.kstack := is_dstkstack1246;
do_memwrite(nstate, nvmcntl, s_dstw_def_w);
else
do_memread_d(nstate, nvmcntl, s_dstw_incdef_w);
end if;
when s_dstw_ind =>
ndpcntl.psr_ccwe := '1';
do_memread_i(nstate, ndpcntl, nvmcntl, s_dstw_ind_w);
when s_dstw_ind_w =>
nstate := s_dstw_ind_w;
if R_IDSTAT.is_dstpc = '0' then
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A = DDST
else
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC (for nn(pc))
end if;
ndpcntl.ounit_bsel := c_ounit_bsel_vmdout;-- OUNIT B = VMDOUT
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
nstate := s_dstw_dec1;
end if;
when s_dstw_def246 =>
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
do_memwrite(nstate, nvmcntl, s_dstw_def_w);
-- destination address states -----------------------------------------------
-- flows:
-- 1 (r) -> do_fork_opa
--
-- 2 (r)+ s_dsta_inc r+=2
-- -> do_fork_opa
--
-- 3 @(r)+ s_dsta_inc req (r); r+=s
-- s_dsta_incdef_w get (r)
-- -> do_fork_opa
--
-- 4 -(r) s_dsta_dec r-=s
-- s_dsta_dec1 ?? FIXME ?? what is done here ??
-- -> do_fork_opa
--
-- 5 @-(r) s_dsta_dec r-=s
-- s_dsta_dec1 req (r)
-- s_dsta_incdef_w get (r)
-- -> do_fork_opa
--
-- 6 n(r) s_dsta_ind req n
-- s_dsta_ind_w get n; ea=r+n
-- s_dsta_dec1 ?? FIXME ?? what is done here ??
-- -> do_fork_opa
--
-- 7 @n(r) s_dsta_ind req n
-- s_dsta_ind_w get n; ea=r+n
-- s_dsta_dec1 req n(r)
-- s_dsta_incdef_w get n(r)
-- -> do_fork_opa
when s_dsta_inc =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_const := "000000010";
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(2)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := DSTREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '0';
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES (for if)
if R_IDSTAT.updt_dstadsrc = '1' then -- prevent stale DSRC copy
ndpcntl.dsrc_we := '1'; -- update DSRC
end if;
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
if DSTDEF = '0' then
do_fork_opa(nstate, R_IDSTAT);
else
do_memread_d(nstate, nvmcntl, s_dsta_incdef_w,
is_pci=>R_IDSTAT.is_dstpc);
end if;
when s_dsta_incdef_w =>
nstate := s_dsta_incdef_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
do_fork_opa(nstate, R_IDSTAT);
end if;
when s_dsta_dec =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_const := "000000010";
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const(2)
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
ndpcntl.ddst_we := '1'; -- update DDST
ndpcntl.gpr_adst := DSTREG;
ndpcntl.gpr_we := '1';
nmmumoni.regmod := '1';
nmmumoni.isdec := '1';
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES (for if)
if R_IDSTAT.updt_dstadsrc = '1' then -- prevent stale DSRC copy
ndpcntl.dsrc_we := '1'; -- update DSRC
end if;
nstate := s_dsta_dec1;
when s_dsta_dec1 =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
if DSTDEF = '0' then -- check here used also by
do_fork_opa(nstate, R_IDSTAT); -- s_dsta_ind flow !!
else
do_memread_d(nstate, nvmcntl, s_dsta_incdef_w);
end if;
when s_dsta_ind =>
do_memread_i(nstate, ndpcntl, nvmcntl, s_dsta_ind_w);
when s_dsta_ind_w =>
nstate := s_dsta_ind_w;
if R_IDSTAT.is_dstpc = '0' then
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A = DDST
else
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC (for nn(pc))
end if;
ndpcntl.ounit_bsel := c_ounit_bsel_vmdout;-- OUNIT B = VMDOUT
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- update DDST
nstate := s_dsta_dec1;
end if;
-- instruction operate states -----------------------------------------------
when s_op_halt => -- HALT
if is_kmode = '1' then -- if in kernel mode execute
nmmumoni.idone := '1';
nstatus.cpugo := '0';
nstatus.cpuhalt := '1';
nstatus.cpurust := c_cpurust_halt;
nstate := s_idle;
else -- otherwise trap
ncpuerr.illhlt := '1';
nstate := s_trap_4; -- trap 4 like 11/70
end if;
when s_op_wait => -- WAIT
nstate := s_op_wait; -- spin here
if is_kmode = '0' then -- but act as nop if not in kernel
nstate := s_idle;
elsif int_pending = '1' or -- bail out if pending interrupt
R_STATUS.cpustep='1' then -- or the instruction is only stepped
nstate := s_idle;
elsif R_STATUS.cmdbusy = '1' then -- suspend if a cp command is pending
nstatus.waitsusp := '1';
nstate := s_idle;
else
nstatus.cpuwait := '1'; -- if spinning here, signal with cpuwait
end if;
when s_op_trap => -- traps
lvector := "0000" & R_IDSTAT.trap_vec; -- vector
do_start_int(nstate, ndpcntl, lvector);
when s_op_reset => -- RESET
if is_kmode = '1' then -- if in kernel mode execute
nbreset := '1';
end if;
nstate := s_idle;
when s_op_rts => -- RTS
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
ndpcntl.gpr_we := '1'; -- load PC with reg(dst)
nstate := s_op_rts_pop;
when s_op_rts_pop =>
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_op_rts_pop_w,
nmmumoni, updt_sp=>'1');
when s_op_rts_pop_w =>
nstate := s_op_rts_pop_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.gpr_adst := DSTREG;
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.gpr_we := '1'; -- load R with (SP)+
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_op_spl => -- SPL
ndpcntl.dres_sel := c_dpath_res_ireg; -- DRES = IREG
ndpcntl.psr_func := c_psr_func_wspl;
if is_kmode = '1' then -- active only in kernel mode
ndpcntl.psr_we := '1';
nstate := s_ifetch; -- unconditionally fetch next
-- instruction like a 11/70
-- no interrupt recognition !
else
do_fork_next(nstate, nstatus, nmmumoni); -- in non-kernel, noop
end if;
when s_op_mcc => -- CLx/SEx
ndpcntl.dres_sel := c_dpath_res_ireg; -- DRES = IREG
ndpcntl.psr_func := c_psr_func_wcc;
ndpcntl.psr_we := '1';
do_fork_next(nstate, nstatus, nmmumoni);
when s_op_br => -- BR
nvmcntl.dspace := '0'; -- prepare do_fork_next_pref
ndpcntl.vmaddr_sel := c_dpath_vmaddr_pc; -- VA = PC
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC
ndpcntl.ounit_bsel := c_ounit_bsel_ireg8;-- OUNIT B = IREG8
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
-- note: cc are NZVC
case brcode(3 downto 1) is
when "000" => -- BR
brcond := '1';
when "001" => -- BNE/BEQ: if Z = x
brcond := PSW.cc(2);
when "010" => -- BGE/BLT: if N xor V = x
brcond := PSW.cc(3) xor PSW.cc(1);
when "011" => -- BGT/BLE: if Z or (N xor V) = x
brcond := PSW.cc(2) or (PSW.cc(3) xor PSW.cc(1));
when "100" => -- BPL/BMI: if N = x
brcond := PSW.cc(3);
when "101" => -- BHI/BLOS:if C or Z = x
brcond := PSW.cc(2) or PSW.cc(0);
when "110" => -- BVC/BVS: if V = x
brcond := PSW.cc(1);
when "111" => -- BCC/BCS: if C = x
brcond := PSW.cc(0);
when others => null;
end case;
ndpcntl.gpr_adst := c_gpr_pc;
if brcond = brcode(0) then -- this coding creates redundant code
ndpcntl.gpr_we := '1'; -- but synthesis optimizes this way !
do_fork_next(nstate, nstatus, nmmumoni);
else
do_fork_next_pref(nstate, nstatus, ndpcntl, nvmcntl, nmmumoni);
end if;
when s_op_mark => -- MARK
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC
ndpcntl.ounit_bsel := c_ounit_bsel_ireg6;-- OUNIT B = IREG6
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- update DSRC (with PC+2*nn)
ndpcntl.gpr_adst := c_gpr_r5; -- fetch r5
ndpcntl.ddst_sel := c_dpath_ddst_dst;
ndpcntl.ddst_we := '1';
nstate := s_op_mark1;
when s_op_mark1 =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A = DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
ndpcntl.gpr_we := '1'; -- load PC with r5
nstate := s_op_mark_pop;
when s_op_mark_pop =>
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_op_mark_pop_w,
nmmumoni, updt_sp=>'1');
when s_op_mark_pop_w =>
nstate := s_op_mark_pop_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.gpr_adst := c_gpr_r5;
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.gpr_we := '1'; -- load R5 with (sp)+
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_op_sob => -- SOB (dec)
-- comment fork_next_pref out (blog 2006-10-02) due to synthesis impact
--nvmcntl.dspace := '0'; -- prepare do_fork_next_pref
--ndpcntl.vmaddr_sel := c_dpath_vmaddr_pc; -- VA = PC
ndpcntl.dres_sel := R_IDSTAT.res_sel;
ndpcntl.gpr_adst := SRCREG;
ndpcntl.gpr_we := '1';
if DP_STAT.ccout_z = '0' then -- if z=0 branch, if z=1 fall thru
nstate := s_op_sob1;
else
--do_fork_next_pref(nstate, ndpcntl, nvmcntl, nmmumoni);
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_op_sob1 => -- SOB (br)
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A = PC
ndpcntl.ounit_bsel := c_ounit_bsel_ireg6;-- OUNIT B = IREG6
ndpcntl.ounit_opsub := '1'; -- OUNIT = A - B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
ndpcntl.gpr_we := '1';
do_fork_next(nstate, nstatus, nmmumoni);
when s_opg_gen =>
nvmcntl.dspace := '0'; -- prepare do_fork_next_pref
ndpcntl.vmaddr_sel := c_dpath_vmaddr_pc; -- VA = PC
ndpcntl.gpr_bytop := R_IDSTAT.is_bytop;
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
if R_IDSTAT.op_mov = '1' then -- in case of MOV xx,R
ndpcntl.gpr_bytop := '0'; -- no bytop, do sign extend
end if;
ndpcntl.psr_ccwe := '1';
if R_IDSTAT.is_dstw_reg = '1' then
ndpcntl.gpr_we := '1';
end if;
if R_IDSTAT.is_rmwop = '1' then
do_memwrite(nstate, nvmcntl, s_opg_gen_rmw_w, macc=>'1');
else
if R_STATUS.prefdone = '1' then
nstatus.prefdone :='0';
nstate := s_ifetch_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ireg_we := '1';
nstate := s_idecode;
end if;
else
if R_IDSTAT.is_dstw_pc = '1' then
nstate := s_idle;
else
do_fork_next_pref(nstate, nstatus, ndpcntl, nvmcntl, nmmumoni);
end if;
end if;
end if;
when s_opg_gen_rmw_w =>
nstate := s_opg_gen_rmw_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_opg_mul => -- MUL (oper)
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.gpr_adst := SRCREG; -- write high order result
ndpcntl.gpr_we := '1';
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- capture high order part
ndpcntl.dtmp_sel := c_dpath_dtmp_drese; -- DTMP = DRESE
ndpcntl.dtmp_we := '1'; -- capture low order part
nstate := s_opg_mul1;
when s_opg_mul1 => -- MUL (write odd reg)
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A = DTMP
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := SRCREG(2 downto 1) & "1";-- write odd reg !
ndpcntl.gpr_we := '1';
ndpcntl.psr_ccwe := '1';
do_fork_next(nstate, nstatus, nmmumoni);
when s_opg_div => -- DIV (load dd_low)
ndpcntl.munit_s_div := '1';
ndpcntl.gpr_asrc := SRCREG(2 downto 1) & "1";-- read odd reg !
ndpcntl.dtmp_sel := c_dpath_dtmp_dsrc;
ndpcntl.dtmp_we := '1';
nstate := s_opg_div_cn;
when s_opg_div_cn => -- DIV (1st...16th cycle)
ndpcntl.munit_s_div_cn := '1';
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dtmp_sel := c_dpath_dtmp_drese; -- DTMP = DRESE
nstate := s_opg_div_cn;
if DP_STAT.div_zero='1' or DP_STAT.div_ovfl='1' then
nstate := s_opg_div_zero;
else
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.dtmp_we := '1'; -- update DTMP
end if;
if DP_STAT.shc_tc = '1' then
nstate := s_opg_div_cr;
end if;
when s_opg_div_cr => -- DIV (reminder correction)
ndpcntl.munit_s_div_cr := '1';
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := DP_STAT.div_cr; -- update DSRC
nstate := s_opg_div_sq;
when s_opg_div_sq => -- DIV (store quotient)
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A=DTMP
ndpcntl.ounit_const := "00000000"&DP_STAT.div_cq;-- OUNIT const = Q corr.
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (q cor)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := SRCREG; -- write result
ndpcntl.gpr_we := '1';
ndpcntl.dtmp_sel := c_dpath_dtmp_dres; -- DTMP = DRES
ndpcntl.dtmp_we := '1'; -- update DTMP (Q)
nstate := s_opg_div_sr;
when s_opg_div_sr => -- DIV (store reminder)
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := SRCREG(2 downto 1) & "1";-- write odd reg !
ndpcntl.gpr_we := '1';
ndpcntl.psr_ccwe := '1';
do_fork_next(nstate, nstatus, nmmumoni);
when s_opg_div_zero => -- DIV (/0 or 0/ abort)
ndpcntl.psr_ccwe := '1';
do_fork_next(nstate, nstatus, nmmumoni);
when s_opg_ash => -- ASH (load shc)
ndpcntl.munit_s_ash := '1';
nstate := s_opg_ash_cn;
when s_opg_ash_cn => -- ASH (shift cycles)
nvmcntl.dspace := '0'; -- prepare do_fork_next_pref
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.gpr_adst := SRCREG; -- write result
ndpcntl.munit_s_ash_cn := '1';
ndpcntl.vmaddr_sel := c_dpath_vmaddr_pc; -- VA = PC
nstate := s_opg_ash_cn;
if DP_STAT.shc_tc = '0' then
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.dsrc_we := '1'; -- update DSRC
else
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_we := '1';
ndpcntl.psr_ccwe := '1';
do_fork_next_pref(nstate, nstatus, ndpcntl, nvmcntl, nmmumoni);
end if;
when s_opg_ashc => -- ASHC (load low, load shc)
ndpcntl.gpr_asrc := SRCREG(2 downto 1) & "1";-- read odd reg !
ndpcntl.dtmp_sel := c_dpath_dtmp_dsrc;
ndpcntl.dtmp_we := '1';
ndpcntl.munit_s_ashc := '1';
nstate := s_opg_ashc_cn;
when s_opg_ashc_cn => -- ASHC (shift cycles)
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dtmp_sel := c_dpath_dtmp_drese; -- DTMP = DRESE
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.gpr_adst := SRCREG; -- write result
ndpcntl.munit_s_ashc_cn := '1';
nstate := s_opg_ashc_cn;
if DP_STAT.shc_tc = '0' then
ndpcntl.dres_sel := R_IDSTAT.res_sel; -- DRES = choice of idec
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.dtmp_we := '1'; -- update DTMP
else
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_we := '1';
ndpcntl.psr_ccwe := '1';
nstate := s_opg_ashc_wl;
end if;
when s_opg_ashc_wl => -- ASHC (write low)
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A = DTMP
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := SRCREG(2 downto 1) & "1";-- write odd reg !
ndpcntl.gpr_we := '1';
do_fork_next(nstate, nstatus, nmmumoni);
-- dsta mode operations -----------------------------------------------------
when s_opa_jsr =>
ndpcntl.gpr_asrc := c_gpr_sp; -- (for else)
ndpcntl.dsrc_sel := c_dpath_dsrc_src; -- DSRC = regfile (for else)
if R_IDSTAT.is_dstmode0 = '1' then
nstate := s_trap_10; -- trap 10 like 11/70
else
ndpcntl.dsrc_we := '1';
nstate := s_opa_jsr1;
end if;
when s_opa_jsr1 =>
ndpcntl.gpr_asrc := SRCREG;
ndpcntl.dtmp_sel := c_dpath_dtmp_dsrc; -- DTMP = regfile
ndpcntl.dtmp_we := '1';
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_const := "000000010";
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(2)
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DDST = DRES
ndpcntl.dsrc_we := '1'; -- update DDST
ndpcntl.gpr_adst := c_gpr_sp;
ndpcntl.gpr_we := '1'; -- update SP
nmmumoni.regmod := '1';
nmmumoni.isdec := '1';
nstate := s_opa_jsr_push;
when s_opa_jsr_push =>
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A=DTMP
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
nvmcntl.dspace := '1';
nvmcntl.kstack := is_kmode;
nvmcntl.wacc := '1';
nvmcntl.req := '1';
nstate := s_opa_jsr_push_w;
when s_opa_jsr_push_w =>
nstate := s_opa_jsr_push_w;
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A=PC
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := SRCREG;
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.gpr_we := '1'; -- load R with PC
nstate := s_opa_jsr2;
end if;
when s_opa_jsr2 =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
ndpcntl.gpr_we := '1'; -- load PC with dsta
do_fork_next(nstate, nstatus, nmmumoni);
when s_opa_jmp =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
if R_IDSTAT.is_dstmode0 = '1' then
nstate := s_trap_10; -- trap 10 like 11/70
else
ndpcntl.gpr_we := '1'; -- load PC with dsta
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_opa_mtp =>
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_opa_mtp_pop_w,
nmmumoni, updt_sp=>'1');
when s_opa_mtp_pop_w =>
nstate := s_opa_mtp_pop_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.dtmp_sel := c_dpath_dtmp_dres; -- DTMP = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.dtmp_we := '1'; -- load DTMP
if R_IDSTAT.is_dstmode0 = '1' then -- handle register access
nstate := s_opa_mtp_reg;
else
case R_IDSTAT.fork_dsta is -- 2nd dsta fork in s_idecode
when c_fork_dsta_def => nstate := s_opa_mtp_mem;
when c_fork_dsta_inc => nstate := s_dsta_inc;
when c_fork_dsta_dec => nstate := s_dsta_dec;
when c_fork_dsta_ind => nstate := s_dsta_ind;
when others => nstate := s_cpufail;
end case;
end if;
end if;
ndpcntl.ddst_sel := c_dpath_ddst_dst; -- DDST = R(DST)
ndpcntl.ddst_we := '1'; -- update DDST (needed for sp)
when s_opa_mtp_reg =>
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A = DTMP
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.psr_ccwe := '1'; -- set cc (from ounit too)
ndpcntl.gpr_mode := PSW.pmode; -- load reg in pmode
ndpcntl.gpr_we := '1';
do_fork_next(nstate, nstatus, nmmumoni);
when s_opa_mtp_mem =>
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A = DTMP
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B = const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.psr_ccwe := '1'; -- set cc (from ounit too)
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst;-- VA = DDST
nvmcntl.dspace := IREG(15); -- msb indicates I/D: 0->I, 1->D
nvmcntl.mode := PSW.pmode;
nvmcntl.wacc := '1';
nvmcntl.req := '1';
nstate := s_opa_mtp_mem_w;
when s_opa_mtp_mem_w =>
nstate := s_opa_mtp_mem_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
do_fork_next(nstate, nstatus, nmmumoni);
end if;
when s_opa_mfp_reg =>
ndpcntl.gpr_mode := PSW.pmode; -- fetch reg in pmode
ndpcntl.ddst_sel := c_dpath_ddst_dst; -- DDST = reg(dst)
ndpcntl.ddst_we := '1';
nstate := s_opa_mfp_dec;
when s_opa_mfp_mem =>
ndpcntl.vmaddr_sel := c_dpath_vmaddr_ddst; -- VA = DDST
if PSW.cmode=c_psw_umode and -- if cm=pm=user then
PSW.cmode=c_psw_umode then -- MFPI works like it
nvmcntl.dspace := '1'; -- were MFPD
else
nvmcntl.dspace := IREG(15); -- msb indicates I/D: 0->I, 1->D
end if;
nvmcntl.mode := PSW.pmode;
nvmcntl.req := '1';
nstate := s_opa_mfp_mem_w;
when s_opa_mfp_mem_w =>
nstate := s_opa_mfp_mem_w;
do_memcheck(nstate, nstatus, imemok);
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
if imemok then
ndpcntl.ddst_we := '1';
nstate := s_opa_mfp_dec;
end if;
when s_opa_mfp_dec =>
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_const := "000000010";
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(2)
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.gpr_adst := c_gpr_sp;
ndpcntl.gpr_we := '1'; -- update SP
nmmumoni.regmod := '1';
nmmumoni.isdec := '1';
nstate := s_opa_mfp_push;
when s_opa_mfp_push =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.psr_ccwe := '1'; -- set cc (from ounit too)
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
nvmcntl.dspace := '1';
nvmcntl.kstack := is_kmode;
nvmcntl.wacc := '1';
nvmcntl.req := '1';
nstate := s_opa_mfp_push_w;
when s_opa_mfp_push_w =>
nstate := s_opa_mfp_push_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
do_fork_next(nstate, nstatus, nmmumoni);
end if;
-- trap and interrupt handling states ---------------------------------------
when s_trap_4 =>
lvector := "0000001"; -- vector (4)
do_start_int(nstate, ndpcntl, lvector);
when s_trap_10 =>
lvector := "0000010"; -- vector (10)
do_start_int(nstate, ndpcntl, lvector);
when s_trap_disp =>
if R_STATUS.trap_mmu = '1' then
nvmcntl.trap_done := '1'; -- mmu trap taken: set ssr0 trap bit
lvector := "0101010"; -- mmu trap: vector (250)
elsif R_STATUS.trap_ysv = '1' then
lvector := "0000001"; -- ysv trap: vector (4)
ncpuerr.ysv := '1';
else
lvector := "0000011"; -- trace trap: vector (14)
end if;
nstatus.trap_mmu := '0'; -- clear pending trap flags
nstatus.trap_ysv := '0'; --
do_start_int(nstate, ndpcntl, lvector);
when s_int_ext =>
lvector := R_STATUS.intvect; -- external vector
do_start_int(nstate, ndpcntl, lvector);
when s_int_getpc =>
nvmcntl.mode := c_psw_kmode; -- fetch PC from kernel D space
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_int_getpc_w, nmmumoni);
when s_int_getpc_w =>
nstate := s_int_getpc_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if VM_STAT.err = '1' then -- in case of vm-err
nstatus.cpugo := '0'; -- non-recoverable error
nstatus.cpurust := c_cpurust_vecfet; -- halt CPU
nstate := s_idle;
end if;
if imemok then
ndpcntl.ddst_we := '1'; -- DDST = new PC
nstate := s_int_getps;
end if;
when s_int_getps =>
nvmcntl.mode := c_psw_kmode; -- fetch PS from kernel D space
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_int_getps_w, nmmumoni);
when s_int_getps_w =>
nstate := s_int_getps_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.psr_func := c_psr_func_wint; -- interupt mode write
do_memcheck(nstate, nstatus, imemok);
if VM_STAT.err = '1' then -- in case of vm-err
nstatus.cpugo := '0'; -- non-recoverable error
nstatus.cpurust := c_cpurust_vecfet; -- halt CPU
nstate := s_idle;
end if;
if imemok then
ndpcntl.psr_we := '1'; -- store new PS
nstate := s_int_getsp;
end if;
when s_int_getsp =>
ndpcntl.gpr_asrc := c_gpr_sp;
ndpcntl.dsrc_we := '1'; -- DSRC = SP (in new mode)
nstate := s_int_decsp;
when s_int_decsp =>
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_const := "000000010"; -- OUNIT const=2
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.gpr_adst := c_gpr_sp;
ndpcntl.gpr_we := '1'; -- update SP too
nstate := s_int_pushps;
when s_int_pushps =>
ndpcntl.ounit_asel := c_ounit_asel_dtmp; -- OUNIT A=DTMP (old PS)
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
nvmcntl.wacc := '1'; -- write mem
nvmcntl.dspace := '1';
nvmcntl.kstack := is_kmode;
nvmcntl.req := '1';
nstate := s_int_pushps_w;
when s_int_pushps_w =>
ndpcntl.ounit_asel := c_ounit_asel_dsrc; -- OUNIT A=DSRC
ndpcntl.ounit_const := "000000010"; -- OUNIT const=2
ndpcntl.ounit_bsel := c_ounit_bsel_const;-- OUNIT B=const
ndpcntl.ounit_opsub := '1'; -- OUNIT = A-B
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.dsrc_sel := c_dpath_dsrc_res; -- DSRC = DRES
ndpcntl.gpr_adst := c_gpr_sp;
nstate := s_int_pushps_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.dsrc_we := '1'; -- update DSRC
ndpcntl.gpr_we := '1'; -- update SP too
nstate := s_int_pushpc;
end if;
when s_int_pushpc =>
ndpcntl.ounit_asel := c_ounit_asel_pc; -- OUNIT A=PC
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.vmaddr_sel := c_dpath_vmaddr_dsrc; -- VA = DSRC
nvmcntl.wacc := '1'; -- write mem
nvmcntl.dspace := '1';
nvmcntl.kstack := is_kmode;
nvmcntl.req := '1';
nstate := s_int_pushpc_w;
when s_int_pushpc_w =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
nstate := s_int_pushpc_w;
do_memcheck(nstate, nstatus, imemok);
if imemok then
nstatus.do_intrsv := '0'; -- signal end of rsv
ndpcntl.gpr_we := '1'; -- load new PC
do_fork_next(nstate, nstatus, nmmumoni); -- ???
end if;
-- return from trap or interrupt handling states ----------------------------
when s_rti_getpc =>
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_rti_getpc_w,
nmmumoni, updt_sp=>'1');
when s_rti_getpc_w =>
nstate := s_rti_getpc_w;
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
ndpcntl.ddst_sel := c_dpath_ddst_res; -- DDST = DRES
do_memcheck(nstate, nstatus, imemok);
if imemok then
ndpcntl.ddst_we := '1'; -- DDST = new PC
nstate := s_rti_getps;
end if;
when s_rti_getps =>
do_memread_srcinc(nstate, ndpcntl, nvmcntl, s_rti_getps_w,
nmmumoni, updt_sp=>'1');
when s_rti_getps_w =>
nstate := s_rti_getps_w;
do_memcheck(nstate, nstatus, imemok);
ndpcntl.dres_sel := c_dpath_res_vmdout; -- DRES = VMDOUT
if is_kmode = '1' then -- if in kernel mode
ndpcntl.psr_func := c_psr_func_wall; -- write all fields
else
ndpcntl.psr_func := c_psr_func_wrti; -- otherwise filter
end if;
if imemok then
ndpcntl.psr_we := '1'; -- load new PS
nstate := s_rti_newpc;
end if;
when s_rti_newpc =>
ndpcntl.ounit_asel := c_ounit_asel_ddst; -- OUNIT A=DDST
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const (0)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_adst := c_gpr_pc;
ndpcntl.gpr_we := '1'; -- load new PC
if R_IDSTAT.op_rtt = '1' then -- if RTT instruction
nstate := s_ifetch; -- force fetch
else -- otherwise RTI
do_fork_next(nstate, nstatus, nmmumoni);
end if;
-- exception abort states ---------------------------------------------------
when s_vmerr =>
nstate := s_cpufail;
-- setup for R_VMSTAT.err_rsv='1'
ndpcntl.ounit_azero := '1'; -- OUNIT A = 0
ndpcntl.ounit_const := "000000100"; -- emergency stack pointer
ndpcntl.ounit_bsel := c_ounit_bsel_const; -- OUNIT B=const(vector)
ndpcntl.dres_sel := c_dpath_res_ounit; -- DRES = OUNIT
ndpcntl.gpr_mode := c_psw_kmode; -- set kmode SP to 4
ndpcntl.gpr_adst := c_gpr_sp;
nstatus.trap_mmu :='0'; -- drop pending mmu trap
if R_VMSTAT.fail = '1' then -- vmbox failure
nstatus.cpugo := '0'; -- halt cpu
nstatus.cpurust := c_cpurust_vfail;
nstate := s_idle;
elsif R_STATUS.do_intrsv = '1' then -- double error
nstatus.cpugo := '0'; -- give up, HALT cpu
nstatus.cpurust := c_cpurust_recrsv;
nstate := s_idle;
elsif R_VMSTAT.err = '1' then -- normal vm errors
if R_VMSTAT.err_rsv = '1' then
nstatus.do_intrsv := '1'; -- signal start of rsv
ndpcntl.gpr_we := '1';
if R_VMSTAT.err_odd='1' or R_VMSTAT.err_mmu='1' then
ncpuerr.adderr := '1';
elsif R_VMSTAT.err_nxm = '1' then
ncpuerr.nxm := '1';
elsif R_VMSTAT.err_iobto = '1' then
ncpuerr.iobto := '1';
end if;
ncpuerr.rsv := '1';
nstate := s_trap_4;
elsif R_VMSTAT.err_odd = '1' then
ncpuerr.adderr := '1';
nstate := s_trap_4;
elsif R_VMSTAT.err_nxm = '1' then
ncpuerr.nxm := '1';
nstate := s_trap_4;
elsif R_VMSTAT.err_iobto = '1' then
ncpuerr.iobto := '1';
nstate := s_trap_4;
elsif R_VMSTAT.err_mmu = '1' then
lvector := "0101010"; -- vector (250)
do_start_int(nstate, ndpcntl, lvector);
end if;
end if;
when s_cpufail =>
nstatus.cpugo := '0';
nstatus.cpurust := c_cpurust_sfail;
nstate := s_idle;
when others =>
nstate := s_cpufail; --!!! catch undefined states !!!
end case;
if nstatus.cmdack = '1' then -- cmdack in next cycle ? Yes we test
-- nstatus here !!
nstatus.cmdbusy := '0';
ndpcntl.cpdout_we := '1';
end if;
N_STATE <= nstate;
N_STATUS <= nstatus;
N_CPUERR <= ncpuerr;
N_IDSTAT <= nidstat;
CRESET <= ncreset;
BRESET <= nbreset;
INT_ACK <= nintack;
DP_CNTL <= ndpcntl;
VM_CNTL <= nvmcntl;
nmmumoni.regnum := ndpcntl.gpr_adst;
nmmumoni.delta := ndpcntl.ounit_const(3 downto 0);
MMU_MONI <= nmmumoni;
end process proc_next;
proc_cpstat : process (R_STATUS)
begin
CP_STAT <= cp_stat_init;
CP_STAT.cmdbusy <= R_STATUS.cmdbusy;
CP_STAT.cmdack <= R_STATUS.cmdack;
CP_STAT.cmderr <= R_STATUS.cmderr;
CP_STAT.cmdmerr <= R_STATUS.cmdmerr;
CP_STAT.cpugo <= R_STATUS.cpugo;
CP_STAT.cpustep <= R_STATUS.cpustep;
CP_STAT.cpuhalt <= R_STATUS.cpuhalt;
CP_STAT.cpuwait <= R_STATUS.cpuwait;
CP_STAT.cpurust <= R_STATUS.cpurust;
end process proc_cpstat;
end syn;
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