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antonblanchard.microwatt/execute1.vhdl
Paul Mackerras 17fd069640 core: Allow multiple loadstore instructions to be in flight 
The idea here is that we can have multiple instructions in progress at
the same time as long as they all go to the same unit, because that
unit will keep them in order.  If we get an instruction for a
different unit, we wait for all the previous instructions to finish
before executing it.  Since the loadstore unit is the only one that is
currently pipelined, this boils down to saying that loadstore
instructions can go ahead while l_in.in_progress = 1 but other
instructions have to wait until it is 0.

This gives a 2% increase on coremark performance on the Arty A7-100
(from ~190 to ~194).

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2021-01-19 12:16:41 +11:00

1266 lines
45 KiB
VHDL
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library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library work;
use work.decode_types.all;
use work.common.all;
use work.helpers.all;
use work.crhelpers.all;
use work.insn_helpers.all;
use work.ppc_fx_insns.all;
entity execute1 is
generic (
EX1_BYPASS : boolean := true;
HAS_FPU : boolean := true;
-- Non-zero to enable log data collection
LOG_LENGTH : natural := 0
);
port (
clk : in std_ulogic;
rst : in std_ulogic;
-- asynchronous
flush_in : in std_ulogic;
busy_out : out std_ulogic;
e_in : in Decode2ToExecute1Type;
l_in : in Loadstore1ToExecute1Type;
fp_in : in FPUToExecute1Type;
ext_irq_in : std_ulogic;
interrupt_in : std_ulogic;
-- asynchronous
l_out : out Execute1ToLoadstore1Type;
fp_out : out Execute1ToFPUType;
e_out : out Execute1ToWritebackType;
bypass_data : out bypass_data_t;
bypass_cr_data : out cr_bypass_data_t;
dbg_msr_out : out std_ulogic_vector(63 downto 0);
icache_inval : out std_ulogic;
terminate_out : out std_ulogic;
log_out : out std_ulogic_vector(14 downto 0);
log_rd_addr : out std_ulogic_vector(31 downto 0);
log_rd_data : in std_ulogic_vector(63 downto 0);
log_wr_addr : in std_ulogic_vector(31 downto 0)
);
end entity execute1;
architecture behaviour of execute1 is
type reg_type is record
e : Execute1ToWritebackType;
cur_instr : Decode2ToExecute1Type;
busy: std_ulogic;
terminate: std_ulogic;
fp_exception_next : std_ulogic;
trace_next : std_ulogic;
prev_op : insn_type_t;
br_taken : std_ulogic;
mul_in_progress : std_ulogic;
mul_finish : std_ulogic;
div_in_progress : std_ulogic;
cntz_in_progress : std_ulogic;
log_addr_spr : std_ulogic_vector(31 downto 0);
end record;
constant reg_type_init : reg_type :=
(e => Execute1ToWritebackInit,
cur_instr => Decode2ToExecute1Init,
busy => '0', terminate => '0',
fp_exception_next => '0', trace_next => '0', prev_op => OP_ILLEGAL, br_taken => '0',
mul_in_progress => '0', mul_finish => '0', div_in_progress => '0', cntz_in_progress => '0',
others => (others => '0'));
signal r, rin : reg_type;
signal a_in, b_in, c_in : std_ulogic_vector(63 downto 0);
signal cr_in : std_ulogic_vector(31 downto 0);
signal xerc_in : xer_common_t;
signal valid_in : std_ulogic;
signal ctrl: ctrl_t := (others => (others => '0'));
signal ctrl_tmp: ctrl_t := (others => (others => '0'));
signal right_shift, rot_clear_left, rot_clear_right: std_ulogic;
signal rot_sign_ext: std_ulogic;
signal rotator_result: std_ulogic_vector(63 downto 0);
signal rotator_carry: std_ulogic;
signal logical_result: std_ulogic_vector(63 downto 0);
signal countzero_result: std_ulogic_vector(63 downto 0);
signal alu_result: std_ulogic_vector(63 downto 0);
signal adder_result: std_ulogic_vector(63 downto 0);
signal misc_result: std_ulogic_vector(63 downto 0);
signal muldiv_result: std_ulogic_vector(63 downto 0);
signal spr_result: std_ulogic_vector(63 downto 0);
signal result_mux_sel: std_ulogic_vector(2 downto 0);
signal sub_mux_sel: std_ulogic_vector(2 downto 0);
signal next_nia : std_ulogic_vector(63 downto 0);
signal current: Decode2ToExecute1Type;
signal carry_32 : std_ulogic;
signal carry_64 : std_ulogic;
signal overflow_32 : std_ulogic;
signal overflow_64 : std_ulogic;
signal trapval : std_ulogic_vector(4 downto 0);
signal write_cr_mask : std_ulogic_vector(7 downto 0);
signal write_cr_data : std_ulogic_vector(31 downto 0);
-- multiply signals
signal x_to_multiply: MultiplyInputType;
signal multiply_to_x: MultiplyOutputType;
-- divider signals
signal x_to_divider: Execute1ToDividerType;
signal divider_to_x: DividerToExecute1Type;
-- random number generator signals
signal random_raw : std_ulogic_vector(63 downto 0);
signal random_cond : std_ulogic_vector(63 downto 0);
signal random_err : std_ulogic;
-- signals for logging
signal exception_log : std_ulogic;
signal irq_valid_log : std_ulogic;
type privilege_level is (USER, SUPER);
type op_privilege_array is array(insn_type_t) of privilege_level;
constant op_privilege: op_privilege_array := (
OP_ATTN => SUPER,
OP_MFMSR => SUPER,
OP_MTMSRD => SUPER,
OP_RFID => SUPER,
OP_TLBIE => SUPER,
others => USER
);
function instr_is_privileged(op: insn_type_t; insn: std_ulogic_vector(31 downto 0))
return boolean is
begin
if op_privilege(op) = SUPER then
return true;
elsif op = OP_MFSPR or op = OP_MTSPR then
return insn(20) = '1';
else
return false;
end if;
end;
procedure set_carry(e: inout Execute1ToWritebackType;
carry32 : in std_ulogic;
carry : in std_ulogic) is
begin
e.xerc.ca32 := carry32;
e.xerc.ca := carry;
end;
procedure set_ov(e: inout Execute1ToWritebackType;
ov : in std_ulogic;
ov32 : in std_ulogic) is
begin
e.xerc.ov32 := ov32;
e.xerc.ov := ov;
if ov = '1' then
e.xerc.so := '1';
end if;
end;
function calc_ov(msb_a : std_ulogic; msb_b: std_ulogic;
ca: std_ulogic; msb_r: std_ulogic) return std_ulogic is
begin
return (ca xor msb_r) and not (msb_a xor msb_b);
end;
function decode_input_carry(ic : carry_in_t;
xerc : xer_common_t) return std_ulogic is
begin
case ic is
when ZERO =>
return '0';
when CA =>
return xerc.ca;
when OV =>
return xerc.ov;
when ONE =>
return '1';
end case;
end;
function msr_copy(msr: std_ulogic_vector(63 downto 0))
return std_ulogic_vector is
variable msr_out: std_ulogic_vector(63 downto 0);
begin
-- ISA says this:
-- Defined MSR bits are classified as either full func-
-- tion or partial function. Full function MSR bits are
-- saved in SRR1 or HSRR1 when an interrupt other
-- than a System Call Vectored interrupt occurs and
-- restored by rfscv, rfid, or hrfid, while partial func-
-- tion MSR bits are not saved or restored.
-- Full function MSR bits lie in the range 0:32, 37:41, and
-- 48:63, and partial function MSR bits lie in the range
-- 33:36 and 42:47. (Note this is IBM bit numbering).
msr_out := (others => '0');
msr_out(63 downto 31) := msr(63 downto 31);
msr_out(26 downto 22) := msr(26 downto 22);
msr_out(15 downto 0) := msr(15 downto 0);
return msr_out;
end;
-- Tell vivado to keep the hierarchy for the random module so that the
-- net names in the xdc file match.
attribute keep_hierarchy : string;
attribute keep_hierarchy of random_0 : label is "yes";
begin
rotator_0: entity work.rotator
port map (
rs => c_in,
ra => a_in,
shift => b_in(6 downto 0),
insn => e_in.insn,
is_32bit => e_in.is_32bit,
right_shift => right_shift,
arith => e_in.is_signed,
clear_left => rot_clear_left,
clear_right => rot_clear_right,
sign_ext_rs => rot_sign_ext,
result => rotator_result,
carry_out => rotator_carry
);
logical_0: entity work.logical
port map (
rs => c_in,
rb => b_in,
op => e_in.insn_type,
invert_in => e_in.invert_a,
invert_out => e_in.invert_out,
result => logical_result,
datalen => e_in.data_len
);
countzero_0: entity work.zero_counter
port map (
clk => clk,
rs => c_in,
count_right => e_in.insn(10),
is_32bit => e_in.is_32bit,
result => countzero_result
);
multiply_0: entity work.multiply
port map (
clk => clk,
m_in => x_to_multiply,
m_out => multiply_to_x
);
divider_0: entity work.divider
port map (
clk => clk,
rst => rst,
d_in => x_to_divider,
d_out => divider_to_x
);
random_0: entity work.random
port map (
clk => clk,
data => random_cond,
raw => random_raw,
err => random_err
);
dbg_msr_out <= ctrl.msr;
log_rd_addr <= r.log_addr_spr;
a_in <= e_in.read_data1;
b_in <= e_in.read_data2;
c_in <= e_in.read_data3;
cr_in <= e_in.cr;
-- XER forwarding. To avoid having to track XER hazards, we use
-- the previously latched value. Since the XER common bits
-- (SO, OV[32] and CA[32]) are only modified by instructions that are
-- handled here, we can just forward the result being sent to
-- writeback.
xerc_in <= r.e.xerc when r.e.write_xerc_enable = '1' or r.busy = '1' else e_in.xerc;
with e_in.unit select busy_out <=
l_in.busy or r.busy or fp_in.busy when LDST,
l_in.busy or l_in.in_progress or r.busy or fp_in.busy when others;
valid_in <= e_in.valid and not busy_out and not flush_in;
terminate_out <= r.terminate;
current <= e_in when r.busy = '0' else r.cur_instr;
-- Result mux
with current.result_sel select alu_result <=
adder_result when "000",
logical_result when "001",
rotator_result when "010",
muldiv_result when "011",
countzero_result when "100",
spr_result when "101",
next_nia when "110",
misc_result when others;
execute1_0: process(clk)
begin
if rising_edge(clk) then
if rst = '1' then
r <= reg_type_init;
ctrl.tb <= (others => '0');
ctrl.dec <= (others => '0');
ctrl.msr <= (MSR_SF => '1', MSR_LE => '1', others => '0');
else
r <= rin;
ctrl <= ctrl_tmp;
if valid_in = '1' then
report "execute " & to_hstring(e_in.nia) & " op=" & insn_type_t'image(e_in.insn_type) &
" wr=" & to_hstring(rin.e.write_reg) & " we=" & std_ulogic'image(rin.e.write_enable) &
" tag=" & integer'image(rin.e.instr_tag.tag) & std_ulogic'image(rin.e.instr_tag.valid);
end if;
end if;
end if;
end process;
-- Data path for integer instructions
execute1_dp: process(all)
variable a_inv : std_ulogic_vector(63 downto 0);
variable b_or_m1 : std_ulogic_vector(63 downto 0);
variable sum_with_carry : std_ulogic_vector(64 downto 0);
variable sign1, sign2 : std_ulogic;
variable abs1, abs2 : signed(63 downto 0);
variable addend : std_ulogic_vector(127 downto 0);
variable addg6s : std_ulogic_vector(63 downto 0);
variable crbit : integer range 0 to 31;
variable isel_result : std_ulogic_vector(63 downto 0);
variable darn : std_ulogic_vector(63 downto 0);
variable setb_result : std_ulogic_vector(63 downto 0);
variable mfcr_result : std_ulogic_vector(63 downto 0);
variable lo, hi : integer;
variable l : std_ulogic;
variable zerohi, zerolo : std_ulogic;
variable msb_a, msb_b : std_ulogic;
variable a_lt : std_ulogic;
variable a_lt_lo : std_ulogic;
variable a_lt_hi : std_ulogic;
variable newcrf : std_ulogic_vector(3 downto 0);
variable bf, bfa : std_ulogic_vector(2 downto 0);
variable crnum : crnum_t;
variable scrnum : crnum_t;
variable cr_operands : std_ulogic_vector(1 downto 0);
variable crresult : std_ulogic;
variable bt, ba, bb : std_ulogic_vector(4 downto 0);
variable btnum : integer range 0 to 3;
variable banum, bbnum : integer range 0 to 31;
variable j : integer;
begin
-- Main adder
if e_in.invert_a = '0' then
a_inv := a_in;
else
a_inv := not a_in;
end if;
if e_in.addm1 = '0' then
b_or_m1 := b_in;
else
b_or_m1 := (others => '1');
end if;
sum_with_carry := ppc_adde(a_inv, b_or_m1,
decode_input_carry(e_in.input_carry, xerc_in));
adder_result <= sum_with_carry(63 downto 0);
carry_32 <= sum_with_carry(32) xor a_inv(32) xor b_in(32);
carry_64 <= sum_with_carry(64);
overflow_32 <= calc_ov(a_inv(31), b_in(31), carry_32, sum_with_carry(31));
overflow_64 <= calc_ov(a_inv(63), b_in(63), carry_64, sum_with_carry(63));
-- signals to multiply and divide units
sign1 := '0';
sign2 := '0';
if e_in.is_signed = '1' then
if e_in.is_32bit = '1' then
sign1 := a_in(31);
sign2 := b_in(31);
else
sign1 := a_in(63);
sign2 := b_in(63);
end if;
end if;
-- take absolute values
if sign1 = '0' then
abs1 := signed(a_in);
else
abs1 := - signed(a_in);
end if;
if sign2 = '0' then
abs2 := signed(b_in);
else
abs2 := - signed(b_in);
end if;
-- Interface to multiply and divide units
x_to_divider.is_signed <= e_in.is_signed;
x_to_divider.is_32bit <= e_in.is_32bit;
x_to_divider.is_extended <= '0';
x_to_divider.is_modulus <= '0';
if e_in.insn_type = OP_MOD then
x_to_divider.is_modulus <= '1';
end if;
addend := (others => '0');
if e_in.insn(26) = '0' then
-- integer multiply-add, major op 4 (if it is a multiply)
addend(63 downto 0) := c_in;
if e_in.is_signed = '1' then
addend(127 downto 64) := (others => c_in(63));
end if;
end if;
if (sign1 xor sign2) = '1' then
addend := not addend;
end if;
x_to_multiply.is_32bit <= e_in.is_32bit;
x_to_multiply.not_result <= sign1 xor sign2;
x_to_multiply.addend <= addend;
x_to_divider.neg_result <= sign1 xor (sign2 and not x_to_divider.is_modulus);
if e_in.is_32bit = '0' then
-- 64-bit forms
x_to_multiply.data1 <= std_ulogic_vector(abs1);
x_to_multiply.data2 <= std_ulogic_vector(abs2);
if e_in.insn_type = OP_DIVE then
x_to_divider.is_extended <= '1';
end if;
x_to_divider.dividend <= std_ulogic_vector(abs1);
x_to_divider.divisor <= std_ulogic_vector(abs2);
else
-- 32-bit forms
x_to_multiply.data1 <= x"00000000" & std_ulogic_vector(abs1(31 downto 0));
x_to_multiply.data2 <= x"00000000" & std_ulogic_vector(abs2(31 downto 0));
x_to_divider.is_extended <= '0';
if e_in.insn_type = OP_DIVE then -- extended forms
x_to_divider.dividend <= std_ulogic_vector(abs1(31 downto 0)) & x"00000000";
else
x_to_divider.dividend <= x"00000000" & std_ulogic_vector(abs1(31 downto 0));
end if;
x_to_divider.divisor <= x"00000000" & std_ulogic_vector(abs2(31 downto 0));
end if;
case current.sub_select(1 downto 0) is
when "00" =>
muldiv_result <= multiply_to_x.result(63 downto 0);
when "01" =>
muldiv_result <= multiply_to_x.result(127 downto 64);
when "10" =>
muldiv_result <= multiply_to_x.result(63 downto 32) &
multiply_to_x.result(63 downto 32);
when others =>
muldiv_result <= divider_to_x.write_reg_data;
end case;
-- Compute misc_result
case current.sub_select is
when "000" =>
misc_result <= (others => '0');
when "001" =>
-- addg6s
addg6s := (others => '0');
for i in 0 to 14 loop
lo := i * 4;
hi := (i + 1) * 4;
if (a_in(hi) xor b_in(hi) xor sum_with_carry(hi)) = '0' then
addg6s(lo + 3 downto lo) := "0110";
end if;
end loop;
if sum_with_carry(64) = '0' then
addg6s(63 downto 60) := "0110";
end if;
misc_result <= addg6s;
when "010" =>
-- isel
crbit := to_integer(unsigned(insn_bc(e_in.insn)));
if cr_in(31-crbit) = '1' then
isel_result := a_in;
else
isel_result := b_in;
end if;
misc_result <= isel_result;
when "011" =>
-- darn
darn := (others => '1');
if random_err = '0' then
case e_in.insn(17 downto 16) is
when "00" =>
darn := x"00000000" & random_cond(31 downto 0);
when "10" =>
darn := random_raw;
when others =>
darn := random_cond;
end case;
end if;
misc_result <= darn;
when "100" =>
-- mfmsr
misc_result <= ctrl.msr;
when "101" =>
if e_in.insn(20) = '0' then
-- mfcr
mfcr_result := x"00000000" & cr_in;
else
-- mfocrf
crnum := fxm_to_num(insn_fxm(e_in.insn));
mfcr_result := (others => '0');
for i in 0 to 7 loop
lo := (7-i)*4;
hi := lo + 3;
if crnum = i then
mfcr_result(hi downto lo) := cr_in(hi downto lo);
end if;
end loop;
end if;
misc_result <= mfcr_result;
when "110" =>
-- setb
bfa := insn_bfa(e_in.insn);
crbit := to_integer(unsigned(bfa)) * 4;
setb_result := (others => '0');
if cr_in(31 - crbit) = '1' then
setb_result := (others => '1');
elsif cr_in(30 - crbit) = '1' then
setb_result(0) := '1';
end if;
misc_result <= setb_result;
when others =>
misc_result <= (others => '0');
end case;
-- compute comparison results
-- Note, we have done RB - RA, not RA - RB
if e_in.insn_type = OP_CMP then
l := insn_l(e_in.insn);
else
l := not e_in.is_32bit;
end if;
zerolo := not (or (a_in(31 downto 0) xor b_in(31 downto 0)));
zerohi := not (or (a_in(63 downto 32) xor b_in(63 downto 32)));
if zerolo = '1' and (l = '0' or zerohi = '1') then
-- values are equal
trapval <= "00100";
else
a_lt_lo := '0';
a_lt_hi := '0';
if unsigned(a_in(30 downto 0)) < unsigned(b_in(30 downto 0)) then
a_lt_lo := '1';
end if;
if unsigned(a_in(62 downto 31)) < unsigned(b_in(62 downto 31)) then
a_lt_hi := '1';
end if;
if l = '1' then
-- 64-bit comparison
msb_a := a_in(63);
msb_b := b_in(63);
a_lt := a_lt_hi or (zerohi and (a_in(31) xnor b_in(31)) and a_lt_lo);
else
-- 32-bit comparison
msb_a := a_in(31);
msb_b := b_in(31);
a_lt := a_lt_lo;
end if;
if msb_a /= msb_b then
-- Comparison is clear from MSB difference.
-- for signed, 0 is greater; for unsigned, 1 is greater
trapval <= msb_a & msb_b & '0' & msb_b & msb_a;
else
-- MSBs are equal, so signed and unsigned comparisons give the
-- same answer.
trapval <= a_lt & not a_lt & '0' & a_lt & not a_lt;
end if;
end if;
-- CR result mux
bf := insn_bf(e_in.insn);
crnum := to_integer(unsigned(bf));
newcrf := (others => '0');
case current.sub_select is
when "000" =>
-- CMP and CMPL instructions
if e_in.is_signed = '1' then
newcrf := trapval(4 downto 2) & xerc_in.so;
else
newcrf := trapval(1 downto 0) & trapval(2) & xerc_in.so;
end if;
when "001" =>
newcrf := ppc_cmprb(a_in, b_in, insn_l(e_in.insn));
when "010" =>
newcrf := ppc_cmpeqb(a_in, b_in);
when "011" =>
if current.insn(1) = '1' then
-- CR logical instructions
j := (7 - crnum) * 4;
newcrf := cr_in(j + 3 downto j);
bt := insn_bt(e_in.insn);
ba := insn_ba(e_in.insn);
bb := insn_bb(e_in.insn);
btnum := 3 - to_integer(unsigned(bt(1 downto 0)));
banum := 31 - to_integer(unsigned(ba));
bbnum := 31 - to_integer(unsigned(bb));
-- Bits 6-9 of the instruction word give the truth table
-- of the requested logical operation
cr_operands := cr_in(banum) & cr_in(bbnum);
crresult := e_in.insn(6 + to_integer(unsigned(cr_operands)));
for i in 0 to 3 loop
if i = btnum then
newcrf(i) := crresult;
end if;
end loop;
else
-- MCRF
bfa := insn_bfa(e_in.insn);
scrnum := to_integer(unsigned(bfa));
j := (7 - scrnum) * 4;
newcrf := cr_in(j + 3 downto j);
end if;
when "100" =>
-- MCRXRX
newcrf := xerc_in.ov & xerc_in.ca & xerc_in.ov32 & xerc_in.ca32;
when others =>
end case;
if current.insn_type = OP_MTCRF then
if e_in.insn(20) = '0' then
-- mtcrf
write_cr_mask <= insn_fxm(e_in.insn);
else
-- mtocrf: We require one hot priority encoding here
crnum := fxm_to_num(insn_fxm(e_in.insn));
write_cr_mask <= num_to_fxm(crnum);
end if;
write_cr_data <= c_in(31 downto 0);
else
write_cr_mask <= num_to_fxm(crnum);
write_cr_data <= newcrf & newcrf & newcrf & newcrf &
newcrf & newcrf & newcrf & newcrf;
end if;
end process;
execute1_1: process(all)
variable v : reg_type;
variable lo, hi : integer;
variable sh, mb, me : std_ulogic_vector(5 downto 0);
variable bo, bi : std_ulogic_vector(4 downto 0);
variable overflow : std_ulogic;
variable lv : Execute1ToLoadstore1Type;
variable irq_valid : std_ulogic;
variable exception : std_ulogic;
variable illegal : std_ulogic;
variable is_branch : std_ulogic;
variable is_direct_branch : std_ulogic;
variable taken_branch : std_ulogic;
variable abs_branch : std_ulogic;
variable spr_val : std_ulogic_vector(63 downto 0);
variable do_trace : std_ulogic;
variable hold_wr_data : std_ulogic;
variable fv : Execute1ToFPUType;
begin
is_branch := '0';
is_direct_branch := '0';
taken_branch := '0';
abs_branch := '0';
hold_wr_data := '0';
v := r;
v.e := Execute1ToWritebackInit;
v.e.redir_mode := ctrl.msr(MSR_IR) & not ctrl.msr(MSR_PR) &
not ctrl.msr(MSR_LE) & not ctrl.msr(MSR_SF);
v.e.xerc := xerc_in;
lv := Execute1ToLoadstore1Init;
fv := Execute1ToFPUInit;
x_to_multiply.valid <= '0';
x_to_divider.valid <= '0';
v.mul_in_progress := '0';
v.div_in_progress := '0';
v.cntz_in_progress := '0';
v.mul_finish := '0';
spr_result <= (others => '0');
spr_val := (others => '0');
ctrl_tmp <= ctrl;
-- FIXME: run at 512MHz not core freq
ctrl_tmp.tb <= std_ulogic_vector(unsigned(ctrl.tb) + 1);
ctrl_tmp.dec <= std_ulogic_vector(unsigned(ctrl.dec) - 1);
irq_valid := '0';
if ctrl.msr(MSR_EE) = '1' then
if ctrl.dec(63) = '1' then
v.e.intr_vec := 16#900#;
report "IRQ valid: DEC";
irq_valid := '1';
elsif ext_irq_in = '1' then
v.e.intr_vec := 16#500#;
report "IRQ valid: External";
irq_valid := '1';
end if;
end if;
v.terminate := '0';
icache_inval <= '0';
v.busy := '0';
-- Next insn adder used in a couple of places
next_nia <= std_ulogic_vector(unsigned(e_in.nia) + 4);
-- rotator control signals
right_shift <= '1' when e_in.insn_type = OP_SHR else '0';
rot_clear_left <= '1' when e_in.insn_type = OP_RLC or e_in.insn_type = OP_RLCL else '0';
rot_clear_right <= '1' when e_in.insn_type = OP_RLC or e_in.insn_type = OP_RLCR else '0';
rot_sign_ext <= '1' when e_in.insn_type = OP_EXTSWSLI else '0';
v.e.srr1 := (others => '0');
exception := '0';
illegal := '0';
if valid_in = '1' then
v.e.last_nia := e_in.nia;
else
v.e.last_nia := r.e.last_nia;
end if;
v.e.mode_32bit := not ctrl.msr(MSR_SF);
v.e.instr_tag := current.instr_tag;
do_trace := valid_in and ctrl.msr(MSR_SE);
if valid_in = '1' then
v.prev_op := e_in.insn_type;
end if;
-- Determine if there is any exception to be taken
-- before/instead of executing this instruction
if valid_in = '1' and e_in.second = '0' and l_in.in_progress = '0' then
if HAS_FPU and r.fp_exception_next = '1' then
-- This is used for FP-type program interrupts that
-- become pending due to MSR[FE0,FE1] changing from 00 to non-zero.
exception := '1';
v.e.intr_vec := 16#700#;
v.e.srr1(47 - 43) := '1';
v.e.srr1(47 - 47) := '1';
elsif r.trace_next = '1' then
-- Generate a trace interrupt rather than executing the next instruction
-- or taking any asynchronous interrupt
exception := '1';
v.e.intr_vec := 16#d00#;
v.e.srr1(47 - 33) := '1';
if r.prev_op = OP_LOAD or r.prev_op = OP_ICBI or r.prev_op = OP_ICBT or
r.prev_op = OP_DCBT or r.prev_op = OP_DCBST or r.prev_op = OP_DCBF then
v.e.srr1(47 - 35) := '1';
elsif r.prev_op = OP_STORE or r.prev_op = OP_DCBZ or r.prev_op = OP_DCBTST then
v.e.srr1(47 - 36) := '1';
end if;
elsif irq_valid = '1' then
-- Don't deliver the interrupt until we have a valid instruction
-- coming in, so we have a valid NIA to put in SRR0.
exception := '1';
elsif ctrl.msr(MSR_PR) = '1' and instr_is_privileged(e_in.insn_type, e_in.insn) then
-- generate a program interrupt
exception := '1';
v.e.intr_vec := 16#700#;
-- set bit 45 to indicate privileged instruction type interrupt
v.e.srr1(47 - 45) := '1';
report "privileged instruction";
elsif not HAS_FPU and e_in.fac = FPU then
-- make lfd/stfd/lfs/stfs etc. illegal in no-FPU implementations
illegal := '1';
elsif HAS_FPU and ctrl.msr(MSR_FP) = '0' and e_in.fac = FPU then
-- generate a floating-point unavailable interrupt
exception := '1';
v.e.intr_vec := 16#800#;
report "FP unavailable interrupt";
end if;
end if;
if valid_in = '1' and exception = '0' and illegal = '0' and e_in.unit = ALU then
v.cur_instr := e_in;
v.e.valid := '1';
case_0: case e_in.insn_type is
when OP_ILLEGAL =>
-- we need two cycles to write srr0 and 1
-- will need more when we have to write HEIR
illegal := '1';
when OP_SC =>
-- check bit 1 of the instruction is 1 so we know this is sc;
-- 0 would mean scv, so generate an illegal instruction interrupt
-- we need two cycles to write srr0 and 1
if e_in.insn(1) = '1' then
exception := '1';
v.e.intr_vec := 16#C00#;
v.e.last_nia := next_nia;
report "sc";
else
illegal := '1';
end if;
when OP_ATTN =>
-- check bits 1-10 of the instruction to make sure it's attn
-- if not then it is illegal
if e_in.insn(10 downto 1) = "0100000000" then
v.terminate := '1';
report "ATTN";
else
illegal := '1';
end if;
when OP_NOP | OP_DCBF | OP_DCBST | OP_DCBT | OP_DCBTST | OP_ICBT =>
-- Do nothing
when OP_ADD =>
if e_in.output_carry = '1' then
if e_in.input_carry /= OV then
set_carry(v.e, carry_32, carry_64);
else
v.e.xerc.ov := carry_64;
v.e.xerc.ov32 := carry_32;
end if;
end if;
if e_in.oe = '1' then
set_ov(v.e, overflow_64, overflow_32);
end if;
when OP_CMP =>
when OP_TRAP =>
-- trap instructions (tw, twi, td, tdi)
v.e.intr_vec := 16#700#;
-- set bit 46 to say trap occurred
v.e.srr1(47 - 46) := '1';
if or (trapval and insn_to(e_in.insn)) = '1' then
-- generate trap-type program interrupt
exception := '1';
report "trap";
end if;
when OP_ADDG6S =>
when OP_CMPRB =>
when OP_CMPEQB =>
when OP_AND | OP_OR | OP_XOR | OP_POPCNT | OP_PRTY | OP_CMPB | OP_EXTS |
OP_BPERM | OP_BCD =>
when OP_B =>
is_branch := '1';
taken_branch := '1';
is_direct_branch := '1';
abs_branch := e_in.br_abs;
if ctrl.msr(MSR_BE) = '1' then
do_trace := '1';
end if;
when OP_BC | OP_BCREG =>
-- read_data1 is CTR
-- for OP_BCREG, read_data2 is target register (CTR, LR or TAR)
-- If this instruction updates both CTR and LR, then it is
-- doubled; the first instruction decrements CTR and determines
-- whether the branch is taken, and the second does the
-- redirect and the LR update.
bo := insn_bo(e_in.insn);
bi := insn_bi(e_in.insn);
if e_in.second = '0' then
taken_branch := ppc_bc_taken(bo, bi, cr_in, a_in);
else
taken_branch := r.br_taken;
end if;
v.br_taken := taken_branch;
abs_branch := e_in.br_abs;
if e_in.repeat = '0' or e_in.second = '1' then
is_branch := '1';
if e_in.insn_type = OP_BC then
is_direct_branch := '1';
end if;
if ctrl.msr(MSR_BE) = '1' then
do_trace := '1';
end if;
end if;
when OP_RFID =>
v.e.redir_mode := (a_in(MSR_IR) or a_in(MSR_PR)) & not a_in(MSR_PR) &
not a_in(MSR_LE) & not a_in(MSR_SF);
-- Can't use msr_copy here because the partial function MSR
-- bits should be left unchanged, not zeroed.
ctrl_tmp.msr(63 downto 31) <= a_in(63 downto 31);
ctrl_tmp.msr(26 downto 22) <= a_in(26 downto 22);
ctrl_tmp.msr(15 downto 0) <= a_in(15 downto 0);
if a_in(MSR_PR) = '1' then
ctrl_tmp.msr(MSR_EE) <= '1';
ctrl_tmp.msr(MSR_IR) <= '1';
ctrl_tmp.msr(MSR_DR) <= '1';
end if;
-- mark this as a branch so CFAR gets updated
is_branch := '1';
taken_branch := '1';
abs_branch := '1';
if HAS_FPU then
v.fp_exception_next := fp_in.exception and
(a_in(MSR_FE0) or a_in(MSR_FE1));
end if;
do_trace := '0';
when OP_CNTZ =>
v.e.valid := '0';
v.cntz_in_progress := '1';
v.busy := '1';
when OP_ISEL =>
when OP_CROP =>
when OP_MCRXRX =>
when OP_DARN =>
when OP_MFMSR =>
when OP_MFSPR =>
report "MFSPR to SPR " & integer'image(decode_spr_num(e_in.insn)) &
"=" & to_hstring(a_in);
if is_fast_spr(e_in.read_reg1) = '1' then
spr_val := a_in;
if decode_spr_num(e_in.insn) = SPR_XER then
-- bits 0:31 and 35:43 are treated as reserved and return 0s when read using mfxer
spr_val(63 downto 32) := (others => '0');
spr_val(63-32) := xerc_in.so;
spr_val(63-33) := xerc_in.ov;
spr_val(63-34) := xerc_in.ca;
spr_val(63-35 downto 63-43) := "000000000";
spr_val(63-44) := xerc_in.ov32;
spr_val(63-45) := xerc_in.ca32;
end if;
else
spr_val := c_in;
case decode_spr_num(e_in.insn) is
when SPR_TB =>
spr_val := ctrl.tb;
when SPR_TBU =>
spr_val(63 downto 32) := (others => '0');
spr_val(31 downto 0) := ctrl.tb(63 downto 32);
when SPR_DEC =>
spr_val := ctrl.dec;
when SPR_CFAR =>
spr_val := ctrl.cfar;
when SPR_PVR =>
spr_val(63 downto 32) := (others => '0');
spr_val(31 downto 0) := PVR_MICROWATT;
when 724 => -- LOG_ADDR SPR
spr_val := log_wr_addr & r.log_addr_spr;
when 725 => -- LOG_DATA SPR
spr_val := log_rd_data;
v.log_addr_spr := std_ulogic_vector(unsigned(r.log_addr_spr) + 1);
when others =>
-- mfspr from unimplemented SPRs should be a nop in
-- supervisor mode and a program interrupt for user mode
if is_fast_spr(e_in.read_reg1) = '0' and ctrl.msr(MSR_PR) = '1' then
illegal := '1';
end if;
end case;
end if;
spr_result <= spr_val;
when OP_MFCR =>
when OP_MTCRF =>
when OP_MTMSRD =>
if e_in.insn(16) = '1' then
-- just update EE and RI
ctrl_tmp.msr(MSR_EE) <= c_in(MSR_EE);
ctrl_tmp.msr(MSR_RI) <= c_in(MSR_RI);
else
-- Architecture says to leave out bits 3 (HV), 51 (ME)
-- and 63 (LE) (IBM bit numbering)
if e_in.is_32bit = '0' then
ctrl_tmp.msr(63 downto 61) <= c_in(63 downto 61);
ctrl_tmp.msr(59 downto 32) <= c_in(59 downto 32);
end if;
ctrl_tmp.msr(31 downto 13) <= c_in(31 downto 13);
ctrl_tmp.msr(11 downto 1) <= c_in(11 downto 1);
if c_in(MSR_PR) = '1' then
ctrl_tmp.msr(MSR_EE) <= '1';
ctrl_tmp.msr(MSR_IR) <= '1';
ctrl_tmp.msr(MSR_DR) <= '1';
end if;
if HAS_FPU then
v.fp_exception_next := fp_in.exception and
(c_in(MSR_FE0) or c_in(MSR_FE1));
end if;
end if;
when OP_MTSPR =>
report "MTSPR to SPR " & integer'image(decode_spr_num(e_in.insn)) &
"=" & to_hstring(c_in);
if is_fast_spr(e_in.write_reg) then
if decode_spr_num(e_in.insn) = SPR_XER then
v.e.xerc.so := c_in(63-32);
v.e.xerc.ov := c_in(63-33);
v.e.xerc.ca := c_in(63-34);
v.e.xerc.ov32 := c_in(63-44);
v.e.xerc.ca32 := c_in(63-45);
end if;
else
-- slow spr
case decode_spr_num(e_in.insn) is
when SPR_DEC =>
ctrl_tmp.dec <= c_in;
when 724 => -- LOG_ADDR SPR
v.log_addr_spr := c_in(31 downto 0);
when others =>
-- mtspr to unimplemented SPRs should be a nop in
-- supervisor mode and a program interrupt for user mode
if ctrl.msr(MSR_PR) = '1' then
illegal := '1';
end if;
end case;
end if;
when OP_RLC | OP_RLCL | OP_RLCR | OP_SHL | OP_SHR | OP_EXTSWSLI =>
if e_in.output_carry = '1' then
set_carry(v.e, rotator_carry, rotator_carry);
end if;
when OP_SETB =>
when OP_ISYNC =>
v.e.redirect := '1';
v.e.br_offset := std_ulogic_vector(to_unsigned(4, 64));
when OP_ICBI =>
icache_inval <= '1';
when OP_MUL_L64 | OP_MUL_H64 | OP_MUL_H32 =>
v.e.valid := '0';
v.mul_in_progress := '1';
v.busy := '1';
x_to_multiply.valid <= '1';
when OP_DIV | OP_DIVE | OP_MOD =>
v.e.valid := '0';
v.div_in_progress := '1';
v.busy := '1';
x_to_divider.valid <= '1';
when others =>
v.terminate := '1';
report "illegal";
end case;
-- Mispredicted branches cause a redirect
if is_branch = '1' then
if taken_branch = '1' then
ctrl_tmp.cfar <= e_in.nia;
end if;
if taken_branch = '1' then
v.e.br_offset := b_in;
v.e.abs_br := abs_branch;
else
v.e.br_offset := std_ulogic_vector(to_unsigned(4, 64));
end if;
if taken_branch /= e_in.br_pred then
v.e.redirect := '1';
end if;
v.e.br_last := is_direct_branch;
v.e.br_taken := taken_branch;
end if;
elsif valid_in = '1' and exception = '0' and illegal = '0' then
-- instruction for other units, i.e. LDST
if e_in.unit = LDST then
lv.valid := '1';
elsif e_in.unit = NONE then
illegal := '1';
elsif HAS_FPU and e_in.unit = FPU then
fv.valid := '1';
end if;
-- Handling an ITLB miss doesn't count as having executed an instruction
if e_in.insn_type = OP_FETCH_FAILED then
do_trace := '0';
end if;
end if;
-- The following cases all occur when r.busy = 1 and therefore
-- valid_in = 0. Hence they don't happen in the same cycle as any of
-- the cases above which depend on valid_in = 1.
if r.cntz_in_progress = '1' then
-- cnt[lt]z always takes two cycles
v.e.valid := '1';
elsif r.mul_in_progress = '1' or r.div_in_progress = '1' then
if (r.mul_in_progress = '1' and multiply_to_x.valid = '1') or
(r.div_in_progress = '1' and divider_to_x.valid = '1') then
if r.mul_in_progress = '1' then
overflow := '0';
else
overflow := divider_to_x.overflow;
end if;
if r.mul_in_progress = '1' and current.oe = '1' then
-- have to wait until next cycle for overflow indication
v.mul_finish := '1';
v.busy := '1';
else
-- We must test oe because the RC update code in writeback
-- will use the xerc value to set CR0:SO so we must not clobber
-- xerc if OE wasn't set.
if current.oe = '1' then
v.e.xerc.ov := overflow;
v.e.xerc.ov32 := overflow;
if overflow = '1' then
v.e.xerc.so := '1';
end if;
end if;
v.e.valid := '1';
end if;
else
v.busy := '1';
v.mul_in_progress := r.mul_in_progress;
v.div_in_progress := r.div_in_progress;
end if;
elsif r.mul_finish = '1' then
hold_wr_data := '1';
v.e.xerc.ov := multiply_to_x.overflow;
v.e.xerc.ov32 := multiply_to_x.overflow;
if multiply_to_x.overflow = '1' then
v.e.xerc.so := '1';
end if;
v.e.valid := '1';
end if;
if illegal = '1' then
exception := '1';
v.e.intr_vec := 16#700#;
-- Since we aren't doing Hypervisor emulation assist (0xe40) we
-- set bit 44 to indicate we have an illegal
v.e.srr1(47 - 44) := '1';
report "illegal";
end if;
v.e.interrupt := exception;
if do_trace = '1' then
v.trace_next := '1';
end if;
if interrupt_in = '1' then
ctrl_tmp.msr(MSR_SF) <= '1';
ctrl_tmp.msr(MSR_EE) <= '0';
ctrl_tmp.msr(MSR_PR) <= '0';
ctrl_tmp.msr(MSR_SE) <= '0';
ctrl_tmp.msr(MSR_BE) <= '0';
ctrl_tmp.msr(MSR_FP) <= '0';
ctrl_tmp.msr(MSR_FE0) <= '0';
ctrl_tmp.msr(MSR_FE1) <= '0';
ctrl_tmp.msr(MSR_IR) <= '0';
ctrl_tmp.msr(MSR_DR) <= '0';
ctrl_tmp.msr(MSR_RI) <= '0';
ctrl_tmp.msr(MSR_LE) <= '1';
v.trace_next := '0';
v.fp_exception_next := '0';
end if;
if hold_wr_data = '0' then
v.e.write_data := alu_result;
else
v.e.write_data := r.e.write_data;
end if;
v.e.write_reg := current.write_reg;
v.e.write_enable := current.write_reg_enable and v.e.valid and not exception;
v.e.rc := current.rc and v.e.valid and not exception;
v.e.write_cr_data := write_cr_data;
v.e.write_cr_mask := write_cr_mask;
v.e.write_cr_enable := current.output_cr and v.e.valid and not exception;
v.e.write_xerc_enable := current.output_xer and v.e.valid and not exception;
bypass_data.tag.valid <= current.instr_tag.valid and current.write_reg_enable and v.e.valid;
bypass_data.tag.tag <= current.instr_tag.tag;
bypass_data.data <= v.e.write_data;
bypass_cr_data.tag.valid <= current.instr_tag.valid and current.output_cr and v.e.valid;
bypass_cr_data.tag.tag <= current.instr_tag.tag;
for i in 0 to 7 loop
if v.e.write_cr_mask(i) = '1' then
bypass_cr_data.data(i*4 + 3 downto i*4) <= v.e.write_cr_data(i*4 + 3 downto i*4);
else
bypass_cr_data.data(i*4 + 3 downto i*4) <= cr_in(i*4 + 3 downto i*4);
end if;
end loop;
-- Outputs to loadstore1 (async)
lv.op := e_in.insn_type;
lv.nia := e_in.nia;
lv.instr_tag := e_in.instr_tag;
lv.addr1 := a_in;
lv.addr2 := b_in;
lv.data := c_in;
lv.write_reg := e_in.write_reg;
lv.length := e_in.data_len;
lv.byte_reverse := e_in.byte_reverse xnor ctrl.msr(MSR_LE);
lv.sign_extend := e_in.sign_extend;
lv.update := e_in.update;
lv.xerc := xerc_in;
lv.reserve := e_in.reserve;
lv.rc := e_in.rc;
lv.insn := e_in.insn;
-- decode l*cix and st*cix instructions here
if e_in.insn(31 downto 26) = "011111" and e_in.insn(10 downto 9) = "11" and
e_in.insn(5 downto 1) = "10101" then
lv.ci := '1';
end if;
lv.virt_mode := ctrl.msr(MSR_DR);
lv.priv_mode := not ctrl.msr(MSR_PR);
lv.mode_32bit := not ctrl.msr(MSR_SF);
lv.is_32bit := e_in.is_32bit;
lv.repeat := e_in.repeat;
lv.second := e_in.second;
-- Outputs to FPU
fv.op := e_in.insn_type;
fv.nia := e_in.nia;
fv.insn := e_in.insn;
fv.itag := e_in.instr_tag;
fv.single := e_in.is_32bit;
fv.fe_mode := ctrl.msr(MSR_FE0) & ctrl.msr(MSR_FE1);
fv.fra := a_in;
fv.frb := b_in;
fv.frc := c_in;
fv.frt := e_in.write_reg;
fv.rc := e_in.rc;
fv.out_cr := e_in.output_cr;
-- Update registers
rin <= v;
-- update outputs
l_out <= lv;
e_out <= r.e;
e_out.msr <= msr_copy(ctrl.msr);
fp_out <= fv;
exception_log <= exception;
irq_valid_log <= irq_valid;
end process;
e1_log: if LOG_LENGTH > 0 generate
signal log_data : std_ulogic_vector(14 downto 0);
begin
ex1_log : process(clk)
begin
if rising_edge(clk) then
log_data <= ctrl.msr(MSR_EE) & ctrl.msr(MSR_PR) &
ctrl.msr(MSR_IR) & ctrl.msr(MSR_DR) &
exception_log &
irq_valid_log &
interrupt_in &
"000" &
r.e.write_enable &
r.e.valid &
(r.e.redirect or r.e.interrupt) &
r.busy &
flush_in;
end if;
end process;
log_out <= log_data;
end generate;
end architecture behaviour;
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