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A tiny Open POWER ISA softcore written in VHDL 2008
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microwatt/execute1.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 (
SIM : boolean := false;
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 : WritebackToExecute1Type;
-- 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;
bypass2_data : out bypass_data_t;
bypass2_cr_data : out cr_bypass_data_t;
dbg_ctrl_out : out ctrl_t;
icache_inval : out std_ulogic;
terminate_out : out std_ulogic;
-- PMU event buses
wb_events : in WritebackEventType;
ls_events : in Loadstore1EventType;
dc_events : in DcacheEventType;
ic_events : in IcacheEventType;
-- Access to SPRs from core_debug module
dbg_spr_req : in std_ulogic;
dbg_spr_ack : out std_ulogic;
dbg_spr_addr : in std_ulogic_vector(7 downto 0);
dbg_spr_data : out std_ulogic_vector(63 downto 0);
-- debug
sim_dump : in std_ulogic;
sim_dump_done : out std_ulogic;
log_out : out std_ulogic_vector(11 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 side_effect_type is record
terminate : std_ulogic;
icache_inval : std_ulogic;
write_msr : std_ulogic;
write_xerlow : std_ulogic;
write_dec : std_ulogic;
write_cfar : std_ulogic;
write_loga : std_ulogic;
inc_loga : std_ulogic;
write_pmuspr : std_ulogic;
ramspr_write_even : std_ulogic;
ramspr_write_odd : std_ulogic;
mult_32s : std_ulogic;
end record;
constant side_effect_init : side_effect_type := (others => '0');
type actions_type is record
e : Execute1ToWritebackType;
se : side_effect_type;
complete : std_ulogic;
exception : std_ulogic;
trap : std_ulogic;
advance_nia : std_ulogic;
new_msr : std_ulogic_vector(63 downto 0);
take_branch : std_ulogic;
direct_branch : std_ulogic;
start_mul : std_ulogic;
start_div : std_ulogic;
do_trace : std_ulogic;
fp_intr : std_ulogic;
res2_sel : std_ulogic_vector(1 downto 0);
bypass_valid : std_ulogic;
ramspr_odd_data : std_ulogic_vector(63 downto 0);
end record;
constant actions_type_init : actions_type :=
(e => Execute1ToWritebackInit, se => side_effect_init,
new_msr => (others => '0'), res2_sel => "00",
ramspr_odd_data => 64x"0", others => '0');
type reg_stage1_type is record
e : Execute1ToWritebackType;
se : side_effect_type;
busy: std_ulogic;
fp_exception_next : std_ulogic;
trace_next : std_ulogic;
prev_op : insn_type_t;
oe : std_ulogic;
mul_select : std_ulogic_vector(1 downto 0);
res2_sel : std_ulogic_vector(1 downto 0);
spr_select : spr_id;
pmu_spr_num : std_ulogic_vector(4 downto 0);
mul_in_progress : std_ulogic;
mul_finish : std_ulogic;
div_in_progress : std_ulogic;
no_instr_avail : std_ulogic;
instr_dispatch : std_ulogic;
ext_interrupt : std_ulogic;
taken_branch_event : std_ulogic;
br_mispredict : std_ulogic;
msr : std_ulogic_vector(63 downto 0);
xerc : xer_common_t;
xerc_valid : std_ulogic;
ramspr_wraddr : ramspr_index;
ramspr_odd_data : std_ulogic_vector(63 downto 0);
end record;
constant reg_stage1_type_init : reg_stage1_type :=
(e => Execute1ToWritebackInit, se => side_effect_init,
busy => '0',
fp_exception_next => '0', trace_next => '0', prev_op => OP_ILLEGAL,
oe => '0', mul_select => "00", res2_sel => "00",
spr_select => spr_id_init, pmu_spr_num => 5x"0",
mul_in_progress => '0', mul_finish => '0', div_in_progress => '0',
no_instr_avail => '0', instr_dispatch => '0', ext_interrupt => '0',
taken_branch_event => '0', br_mispredict => '0',
msr => 64x"0",
xerc => xerc_init, xerc_valid => '0',
ramspr_wraddr => (others => '0'), ramspr_odd_data => 64x"0");
type reg_stage2_type is record
e : Execute1ToWritebackType;
se : side_effect_type;
ext_interrupt : std_ulogic;
taken_branch_event : std_ulogic;
br_mispredict : std_ulogic;
log_addr_spr : std_ulogic_vector(31 downto 0);
end record;
constant reg_stage2_type_init : reg_stage2_type :=
(e => Execute1ToWritebackInit, se => side_effect_init,
log_addr_spr => 32x"0", others => '0');
signal ex1, ex1in : reg_stage1_type;
signal ex2, ex2in : reg_stage2_type;
signal actions : actions_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 mshort_p : std_ulogic_vector(31 downto 0) := (others => '0');
signal valid_in : std_ulogic;
signal ctrl: ctrl_t := ctrl_t_init;
signal ctrl_tmp: ctrl_t := ctrl_t_init;
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 do_popcnt: std_ulogic;
signal countbits_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 shortmul_result: std_ulogic_vector(63 downto 0);
signal spr_result: std_ulogic_vector(63 downto 0);
signal next_nia : std_ulogic_vector(63 downto 0);
signal s1_sel : std_ulogic_vector(2 downto 0);
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;
signal x_to_mult_32s: MultiplyInputType;
signal mult_32s_to_x: MultiplyOutputType;
-- divider signals
signal x_to_divider: Execute1ToDividerType;
signal divider_to_x: DividerToExecute1Type := DividerToExecute1Init;
-- 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;
-- PMU signals
signal x_to_pmu : Execute1ToPMUType;
signal pmu_to_x : PMUToExecute1Type;
-- signals for logging
signal exception_log : std_ulogic;
signal irq_valid_log : std_ulogic;
-- SPR-related signals
type ramspr_half_t is array(ramspr_index_range) of std_ulogic_vector(63 downto 0);
signal even_sprs : ramspr_half_t := (others => (others => '0'));
signal odd_sprs : ramspr_half_t := (others => (others => '0'));
signal ramspr_even : std_ulogic_vector(63 downto 0);
signal ramspr_odd : std_ulogic_vector(63 downto 0);
signal ramspr_result : std_ulogic_vector(63 downto 0);
signal ramspr_rd_odd : std_ulogic;
signal ramspr_wr_addr : ramspr_index;
signal ramspr_even_wr_data : std_ulogic_vector(63 downto 0);
signal ramspr_even_wr_enab : std_ulogic;
signal ramspr_odd_wr_data : std_ulogic_vector(63 downto 0);
signal ramspr_odd_wr_enab : std_ulogic;
signal stage2_stall : 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;
function intr_srr1(msr: std_ulogic_vector; flags: std_ulogic_vector)
return std_ulogic_vector is
variable srr1: std_ulogic_vector(63 downto 0);
begin
srr1(63 downto 31) := msr(63 downto 31);
srr1(30 downto 27) := flags(14 downto 11);
srr1(26 downto 22) := msr(26 downto 22);
srr1(21 downto 16) := flags(5 downto 0);
srr1(15 downto 0) := msr(15 downto 0);
return srr1;
end;
-- Work out whether a signed value fits into n bits,
-- that is, see if it is in the range -2^(n-1) .. 2^(n-1) - 1
function fits_in_n_bits(val: std_ulogic_vector; n: integer) return boolean is
variable x, xp1: std_ulogic_vector(val'left downto val'right);
begin
x := val;
if val(val'left) = '0' then
x := not val;
end if;
xp1 := bit_reverse(std_ulogic_vector(unsigned(bit_reverse(x)) + 1));
x := x and not xp1;
-- For positive inputs, x has ones at the positions
-- to the left of the leftmost 1 bit in val.
-- For negative inputs, x has ones to the left of
-- the leftmost 0 bit in val.
return x(n - 1) = '1';
end;
function assemble_xer(xerc: xer_common_t; xer_low: std_ulogic_vector)
return std_ulogic_vector is
begin
return 32x"0" & xerc.so & xerc.ov & xerc.ca & "000000000" &
xerc.ov32 & xerc.ca32 & xer_low(17 downto 0);
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
);
countbits_0: entity work.bit_counter
port map (
clk => clk,
rs => c_in,
stall => stage2_stall,
count_right => e_in.insn(10),
is_32bit => e_in.is_32bit,
do_popcnt => do_popcnt,
datalen => e_in.data_len,
result => countbits_result
);
multiply_0: entity work.multiply
port map (
clk => clk,
m_in => x_to_multiply,
m_out => multiply_to_x
);
mult_32s_0: entity work.multiply_32s
port map (
clk => clk,
stall => stage2_stall,
m_in => x_to_mult_32s,
m_out => mult_32s_to_x
);
divider_0: if not HAS_FPU generate
div_0: entity work.divider
port map (
clk => clk,
rst => rst,
d_in => x_to_divider,
d_out => divider_to_x
);
end generate;
random_0: entity work.random
port map (
clk => clk,
data => random_cond,
raw => random_raw,
err => random_err
);
pmu_0: entity work.pmu
port map (
clk => clk,
rst => rst,
p_in => x_to_pmu,
p_out => pmu_to_x
);
dbg_ctrl_out <= ctrl;
log_rd_addr <= ex2.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;
x_to_pmu.occur <= (instr_complete => wb_events.instr_complete,
fp_complete => wb_events.fp_complete,
ld_complete => ls_events.load_complete,
st_complete => ls_events.store_complete,
itlb_miss => ls_events.itlb_miss,
dc_load_miss => dc_events.load_miss,
dc_ld_miss_resolved => dc_events.dcache_refill,
dc_store_miss => dc_events.store_miss,
dtlb_miss => dc_events.dtlb_miss,
dtlb_miss_resolved => dc_events.dtlb_miss_resolved,
icache_miss => ic_events.icache_miss,
itlb_miss_resolved => ic_events.itlb_miss_resolved,
no_instr_avail => ex1.no_instr_avail,
dispatch => ex1.instr_dispatch,
ext_interrupt => ex2.ext_interrupt,
br_taken_complete => ex2.taken_branch_event,
br_mispredict => ex2.br_mispredict,
others => '0');
x_to_pmu.nia <= e_in.nia;
x_to_pmu.addr <= (others => '0');
x_to_pmu.addr_v <= '0';
x_to_pmu.spr_num <= ex1.pmu_spr_num;
x_to_pmu.spr_val <= ex1.e.write_data;
x_to_pmu.run <= '1';
-- XER forwarding. The CA and CA32 bits are only modified by instructions
-- that are handled here, so for them we can just use the result most
-- recently sent to writeback, unless a pipeline flush has happened in the
-- meantime.
-- Hazards for SO/OV/OV32 are handled by control.vhdl as there may be other
-- units writing to them. No forwarding is done because performance of
-- instructions that alter them is not considered significant.
xerc_in.so <= e_in.xerc.so;
xerc_in.ov <= e_in.xerc.ov;
xerc_in.ov32 <= e_in.xerc.ov32;
xerc_in.ca <= ex1.xerc.ca when ex1.xerc_valid = '1' else e_in.xerc.ca;
xerc_in.ca32 <= ex1.xerc.ca32 when ex1.xerc_valid = '1' else e_in.xerc.ca32;
-- N.B. the busy signal from each source includes the
-- stage2 stall from that source in it.
busy_out <= l_in.busy or ex1.busy or fp_in.busy;
valid_in <= e_in.valid and not (busy_out or flush_in or ex1.e.redirect or ex1.e.interrupt);
-- SPRs stored in two small RAM arrays (two so that we can read and write
-- two SPRs in each cycle).
ramspr_read: process(all)
variable even_rd_data, odd_rd_data : std_ulogic_vector(63 downto 0);
variable wr_addr : ramspr_index;
variable even_wr_enab, odd_wr_enab : std_ulogic;
variable even_wr_data, odd_wr_data : std_ulogic_vector(63 downto 0);
variable doit : std_ulogic;
begin
-- Read address mux and async RAM reading
if is_X(e_in.ramspr_even_rdaddr) then
even_rd_data := (others => 'X');
else
even_rd_data := even_sprs(to_integer(e_in.ramspr_even_rdaddr));
end if;
if is_X(e_in.ramspr_even_rdaddr) then
odd_rd_data := (others => 'X');
else
odd_rd_data := odd_sprs(to_integer(e_in.ramspr_odd_rdaddr));
end if;
-- Write address and data muxes
doit := ex1.e.valid and not stage2_stall and not flush_in;
even_wr_enab := (ex1.se.ramspr_write_even and doit) or interrupt_in.intr;
odd_wr_enab := (ex1.se.ramspr_write_odd and doit) or interrupt_in.intr;
if interrupt_in.intr = '1' then
wr_addr := RAMSPR_SRR0;
else
wr_addr := ex1.ramspr_wraddr;
end if;
if interrupt_in.intr = '1' then
even_wr_data := ex2.e.last_nia;
odd_wr_data := intr_srr1(ctrl.msr, interrupt_in.srr1);
else
even_wr_data := ex1.e.write_data;
odd_wr_data := ex1.ramspr_odd_data;
end if;
ramspr_wr_addr <= wr_addr;
ramspr_even_wr_data <= even_wr_data;
ramspr_even_wr_enab <= even_wr_enab;
ramspr_odd_wr_data <= odd_wr_data;
ramspr_odd_wr_enab <= odd_wr_enab;
-- SPR RAM read with write data bypass
-- We assume no instruction executes in the cycle immediately following
-- an interrupt, so we don't need to bypass interrupt data
if ex1.se.ramspr_write_even = '1' and e_in.ramspr_even_rdaddr = ex1.ramspr_wraddr then
ramspr_even <= ex1.e.write_data;
else
ramspr_even <= even_rd_data;
end if;
if ex1.se.ramspr_write_odd = '1' and e_in.ramspr_odd_rdaddr = ex1.ramspr_wraddr then
ramspr_odd <= ex1.ramspr_odd_data;
else
ramspr_odd <= odd_rd_data;
end if;
if e_in.ramspr_rd_odd = '0' then
ramspr_result <= ramspr_even;
else
ramspr_result <= ramspr_odd;
end if;
end process;
ramspr_write: process(clk)
begin
if rising_edge(clk) then
if ramspr_even_wr_enab = '1' then
assert not is_X(ramspr_wr_addr) report "Writing to unknown address" severity FAILURE;
even_sprs(to_integer(ramspr_wr_addr)) <= ramspr_even_wr_data;
report "writing even spr " & integer'image(to_integer(ramspr_wr_addr)) & " data=" &
to_hstring(ramspr_even_wr_data);
end if;
if ramspr_odd_wr_enab = '1' then
assert not is_X(ramspr_wr_addr) report "Writing to unknown address" severity FAILURE;
odd_sprs(to_integer(ramspr_wr_addr)) <= ramspr_odd_wr_data;
report "writing odd spr " & integer'image(to_integer(ramspr_wr_addr)) & " data=" &
to_hstring(ramspr_odd_wr_data);
end if;
end if;
end process;
-- First stage result mux
s1_sel <= e_in.result_sel when ex1.busy = '0' else "100";
with s1_sel select alu_result <=
adder_result when "000",
logical_result when "001",
rotator_result when "010",
shortmul_result when "011",
muldiv_result when "100",
ramspr_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
ex1 <= reg_stage1_type_init;
ex2 <= reg_stage2_type_init;
ctrl <= ctrl_t_init;
ctrl.msr <= (MSR_SF => '1', MSR_LE => '1', others => '0');
ex1.msr <= (MSR_SF => '1', MSR_LE => '1', others => '0');
else
ex1 <= ex1in;
ex2 <= ex2in;
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(ex1in.e.write_reg) & " we=" & std_ulogic'image(ex1in.e.write_enable) &
" tag=" & integer'image(ex1in.e.instr_tag.tag) & std_ulogic'image(ex1in.e.instr_tag.valid);
end if;
-- We mustn't get stalled on a cycle where execute2 is
-- completing an instruction or generating an interrupt
if ex2.e.valid = '1' or ex2.e.interrupt = '1' then
assert stage2_stall = '0' severity failure;
end if;
end if;
end if;
end process;
ex_dbg_spr: process(clk)
begin
if rising_edge(clk) then
if rst = '0' and dbg_spr_req = '1' then
if e_in.dbg_spr_access = '1' and dbg_spr_ack = '0' then
if dbg_spr_addr(7) = '1' then
dbg_spr_data <= ramspr_result;
else
dbg_spr_data <= assemble_xer(xerc_in, ctrl.xer_low);
end if;
dbg_spr_ack <= '1';
end if;
else
dbg_spr_ack <= '0';
end if;
end if;
end process;
-- Data path for integer instructions (first execute stage)
execute1_dp: process(all)
variable a_inv : 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;
sum_with_carry := ppc_adde(a_inv, b_in,
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 multiplier
addend := (others => '0');
if e_in.reg_valid3 = '1' 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;
x_to_multiply.data1 <= std_ulogic_vector(a_in);
x_to_multiply.data2 <= std_ulogic_vector(b_in);
x_to_multiply.is_signed <= e_in.is_signed;
x_to_multiply.subtract <= '0';
x_to_multiply.addend <= addend;
-- Interface to divide unit
if not HAS_FPU then
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;
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;
x_to_divider.flush <= flush_in;
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
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_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;
end if;
-- signals to 32-bit multiplier
x_to_mult_32s.data1 <= 32x"0" & a_in(31 downto 0);
x_to_mult_32s.data2 <= 32x"0" & b_in(31 downto 0);
x_to_mult_32s.is_signed <= e_in.is_signed;
-- The following are unused, but set here to avoid X states
x_to_mult_32s.subtract <= '0';
x_to_mult_32s.addend <= (others => '0');
shortmul_result <= std_ulogic_vector(resize(signed(mshort_p), 64));
case ex1.mul_select 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 e_in.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 <= ex1.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 is_X(a_in) or is_X(b_in) then
a_lt_lo := 'X';
a_lt_hi := 'X';
else
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;
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);
newcrf := (others => '0');
case e_in.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 is_X(e_in.insn) then
newcrf := (others => 'X');
elsif e_in.insn(1) = '1' then
-- CR logical instructions
crnum := to_integer(unsigned(bf));
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.ov32 & xerc_in.ca & xerc_in.ca32;
when others =>
end case;
if e_in.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;
elsif e_in.output_cr = '1' and not is_X(bf) then
crnum := to_integer(unsigned(bf));
write_cr_mask <= num_to_fxm(crnum);
else
write_cr_mask <= (others => '0');
end if;
for i in 0 to 7 loop
if write_cr_mask(i) = '0' then
write_cr_data(i*4 + 3 downto i*4) <= cr_in(i*4 + 3 downto i*4);
elsif e_in.insn_type = OP_MTCRF then
write_cr_data(i*4 + 3 downto i*4) <= c_in(i*4 + 3 downto i*4);
else
write_cr_data(i*4 + 3 downto i*4) <= newcrf;
end if;
end loop;
end process;
execute1_actions: process(all)
variable v: actions_type;
variable bo, bi : std_ulogic_vector(4 downto 0);
variable illegal : std_ulogic;
variable privileged : std_ulogic;
variable slow_op : std_ulogic;
variable owait : std_ulogic;
variable srr1 : std_ulogic_vector(63 downto 0);
begin
v := actions_type_init;
v.e.write_data := alu_result;
v.e.write_reg := e_in.write_reg;
v.e.write_enable := e_in.write_reg_enable;
v.e.rc := e_in.rc;
v.e.write_cr_data := write_cr_data;
v.e.write_cr_mask := write_cr_mask;
v.e.write_cr_enable := e_in.output_cr;
v.e.write_xerc_enable := e_in.output_xer;
v.e.xerc := xerc_in;
v.new_msr := ex1.msr;
v.e.redir_mode := ex1.msr(MSR_IR) & not ex1.msr(MSR_PR) &
not ex1.msr(MSR_LE) & not ex1.msr(MSR_SF);
v.e.intr_vec := 16#700#;
v.e.mode_32bit := not ex1.msr(MSR_SF);
v.e.instr_tag := e_in.instr_tag;
v.e.last_nia := e_in.nia;
v.e.br_offset := 64x"4";
v.se.ramspr_write_even := e_in.ramspr_write_even;
v.se.ramspr_write_odd := e_in.ramspr_write_odd;
v.ramspr_odd_data := c_in;
if e_in.dec_ctr = '1' then
v.ramspr_odd_data := std_ulogic_vector(unsigned(ramspr_odd) - 1);
end if;
-- Note the difference between v.exception and v.trap:
-- v.exception signals a condition that prevents execution of the
-- instruction, and hence shouldn't depend on operand data, so as to
-- avoid timing chains through both data and control paths.
-- v.trap also means we want to generate an interrupt, but doesn't
-- cancel instruction execution (hence we need to avoid setting any
-- side-effect flags or write enables when generating a trap).
-- With v.trap = 1 we will assert both ex1.e.valid and ex1.e.interrupt
-- to writeback, and it will complete the instruction and take
-- and interrupt. It is OK for v.trap to depend on operand data.
illegal := '0';
privileged := '0';
slow_op := '0';
owait := '0';
if ex1.msr(MSR_PR) = '1' and instr_is_privileged(e_in.insn_type, e_in.insn) then
privileged := '1';
end if;
if (not HAS_FPU and e_in.fac = FPU) or e_in.unit = NONE then
-- make lfd/stfd/lfs/stfs etc. illegal in no-FPU implementations
illegal := '1';
end if;
v.do_trace := ex1.msr(MSR_SE);
case_0: case e_in.insn_type is
when OP_ILLEGAL =>
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
if e_in.insn(1) = '1' then
v.trap := '1';
v.advance_nia := '1';
v.e.intr_vec := 16#C00#;
if e_in.valid = '1' then
report "sc";
end if;
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.se.terminate := '1';
if e_in.valid = '1' then
report "ATTN";
end if;
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
v.trap := '1';
if e_in.valid = '1' then
report "trap";
end if;
end if;
when OP_ADDG6S =>
when OP_CMPRB =>
when OP_CMPEQB =>
when OP_AND | OP_OR | OP_XOR | OP_PRTY | OP_CMPB | OP_EXTS |
OP_BPERM | OP_BCD =>
when OP_B =>
v.take_branch := '1';
v.direct_branch := '1';
v.e.br_last := '1';
v.e.br_taken := '1';
v.e.br_offset := b_in;
v.e.abs_br := insn_aa(e_in.insn);
if e_in.br_pred = '0' then
-- should never happen
v.e.redirect := '1';
end if;
if ex1.msr(MSR_BE) = '1' then
v.do_trace := '1';
end if;
v.se.write_cfar := '1';
when OP_BC =>
-- If CTR is being decremented, it is in ramspr_odd.
bo := insn_bo(e_in.insn);
bi := insn_bi(e_in.insn);
v.take_branch := ppc_bc_taken(bo, bi, cr_in, ramspr_odd);
if v.take_branch = '1' then
v.e.br_offset := b_in;
v.e.abs_br := insn_aa(e_in.insn);
end if;
-- Mispredicted branches cause a redirect
if v.take_branch /= e_in.br_pred then
v.e.redirect := '1';
end if;
v.direct_branch := '1';
v.e.br_last := '1';
v.e.br_taken := v.take_branch;
if ex1.msr(MSR_BE) = '1' then
v.do_trace := '1';
end if;
v.se.write_cfar := v.take_branch;
when OP_BCREG =>
-- If CTR is being decremented, it is in ramspr_odd.
-- The target address is in ramspr_result (LR, CTR or TAR).
bo := insn_bo(e_in.insn);
bi := insn_bi(e_in.insn);
v.take_branch := ppc_bc_taken(bo, bi, cr_in, ramspr_odd);
if v.take_branch = '1' then
v.e.br_offset := ramspr_result;
v.e.abs_br := '1';
end if;
-- Indirect branches are never predicted taken
v.e.redirect := v.take_branch;
v.e.br_taken := v.take_branch;
if ex1.msr(MSR_BE) = '1' then
v.do_trace := '1';
end if;
v.se.write_cfar := v.take_branch;
when OP_RFID =>
srr1 := ramspr_odd;
v.e.redir_mode := (srr1(MSR_IR) or srr1(MSR_PR)) & not srr1(MSR_PR) &
not srr1(MSR_LE) & not srr1(MSR_SF);
-- Can't use msr_copy here because the partial function MSR
-- bits should be left unchanged, not zeroed.
v.new_msr(63 downto 31) := srr1(63 downto 31);
v.new_msr(26 downto 22) := srr1(26 downto 22);
v.new_msr(15 downto 0) := srr1(15 downto 0);
if srr1(MSR_PR) = '1' then
v.new_msr(MSR_EE) := '1';
v.new_msr(MSR_IR) := '1';
v.new_msr(MSR_DR) := '1';
end if;
v.se.write_msr := '1';
v.e.br_offset := ramspr_result;
v.e.abs_br := '1';
v.e.redirect := '1';
v.se.write_cfar := '1';
if HAS_FPU then
v.fp_intr := fp_in.exception and
(srr1(MSR_FE0) or srr1(MSR_FE1));
end if;
v.do_trace := '0';
when OP_CNTZ | OP_POPCNT =>
v.res2_sel := "01";
slow_op := '1';
when OP_ISEL =>
when OP_CROP =>
when OP_MCRXRX =>
when OP_DARN =>
when OP_MFMSR =>
when OP_MFSPR =>
if e_in.spr_is_ram = '1' then
if e_in.valid = '1' and not is_X(e_in.insn) then
report "MFSPR to SPR " & integer'image(decode_spr_num(e_in.insn)) &
"=" & to_hstring(alu_result);
end if;
elsif e_in.spr_select.valid = '1' then
if e_in.valid = '1' and not is_X(e_in.insn) then
report "MFSPR to slow SPR " & integer'image(decode_spr_num(e_in.insn));
end if;
slow_op := '1';
if e_in.spr_select.ispmu = '0' then
case e_in.spr_select.sel is
when SPRSEL_LOGD =>
v.se.inc_loga := '1';
when others =>
end case;
v.res2_sel := "10";
else
v.res2_sel := "11";
end if;
else
-- mfspr from unimplemented SPRs should be a nop in
-- supervisor mode and a program interrupt for user mode
if e_in.valid = '1' and not is_X(e_in.insn) then
report "MFSPR to SPR " & integer'image(decode_spr_num(e_in.insn)) &
" invalid";
end if;
if ex1.msr(MSR_PR) = '1' then
illegal := '1';
end if;
end if;
when OP_MFCR =>
when OP_MTCRF =>
when OP_MTMSRD =>
v.se.write_msr := '1';
if e_in.insn(16) = '1' then
-- just update EE and RI
v.new_msr(MSR_EE) := c_in(MSR_EE);
v.new_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
v.new_msr(63 downto 61) := c_in(63 downto 61);
v.new_msr(59 downto 32) := c_in(59 downto 32);
end if;
v.new_msr(31 downto 13) := c_in(31 downto 13);
v.new_msr(11 downto 1) := c_in(11 downto 1);
if c_in(MSR_PR) = '1' then
v.new_msr(MSR_EE) := '1';
v.new_msr(MSR_IR) := '1';
v.new_msr(MSR_DR) := '1';
end if;
if HAS_FPU then
v.fp_intr := fp_in.exception and
(c_in(MSR_FE0) or c_in(MSR_FE1));
end if;
end if;
when OP_MTSPR =>
if e_in.valid = '1' and not is_X(e_in.insn) then
report "MTSPR to SPR " & integer'image(decode_spr_num(e_in.insn)) &
"=" & to_hstring(c_in);
end if;
v.se.write_pmuspr := e_in.spr_select.ispmu;
if e_in.spr_select.valid = '1' and e_in.spr_select.ispmu = '0' then
case e_in.spr_select.sel is
when SPRSEL_XER =>
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);
v.se.write_xerlow := '1';
when SPRSEL_DEC =>
v.se.write_dec := '1';
when SPRSEL_LOGA =>
v.se.write_loga := '1';
when others =>
end case;
end if;
if e_in.spr_select.valid = '0' and e_in.spr_is_ram = '0' then
-- mtspr to unimplemented SPRs should be a nop in
-- supervisor mode and a program interrupt for user mode
if ex1.msr(MSR_PR) = '1' then
illegal := '1';
end if;
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';
when OP_ICBI =>
v.se.icache_inval := '1';
when OP_MUL_L64 =>
if e_in.is_32bit = '1' then
v.se.mult_32s := '1';
v.res2_sel := "00";
slow_op := '1';
else
-- Use standard multiplier
v.start_mul := '1';
slow_op := '1';
owait := '1';
end if;
when OP_MUL_H64 =>
v.start_mul := '1';
slow_op := '1';
owait := '1';
when OP_MUL_H32 =>
v.se.mult_32s := '1';
v.res2_sel := "01";
slow_op := '1';
when OP_DIV | OP_DIVE | OP_MOD =>
if not HAS_FPU then
v.start_div := '1';
slow_op := '1';
owait := '1';
end if;
when OP_FETCH_FAILED =>
-- Handling an ITLB miss doesn't count as having executed an instruction
v.do_trace := '0';
when others =>
if e_in.valid = '1' and e_in.unit = ALU then
report "unhandled insn_type " & insn_type_t'image(e_in.insn_type);
end if;
end case;
if privileged = '1' then
-- generate a program interrupt
v.exception := '1';
-- set bit 45 to indicate privileged instruction type interrupt
v.e.srr1(47 - 45) := '1';
if e_in.valid = '1' then
report "privileged instruction";
end if;
elsif illegal = '1' then
v.exception := '1';
-- 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';
if e_in.valid = '1' then
report "illegal instruction";
end if;
elsif HAS_FPU and ex1.msr(MSR_FP) = '0' and e_in.fac = FPU then
-- generate a floating-point unavailable interrupt
v.exception := '1';
v.e.intr_vec := 16#800#;
if e_in.valid = '1' then
report "FP unavailable interrupt";
end if;
end if;
if e_in.unit = ALU then
v.complete := e_in.valid and not v.exception and not owait;
v.bypass_valid := e_in.valid and not v.exception and not slow_op;
end if;
actions <= v;
end process;
-- First execute stage
execute1_1: process(all)
variable v : reg_stage1_type;
variable overflow : std_ulogic;
variable lv : Execute1ToLoadstore1Type;
variable irq_valid : std_ulogic;
variable exception : std_ulogic;
variable fv : Execute1ToFPUType;
variable go : std_ulogic;
variable bypass_valid : std_ulogic;
begin
v := ex1;
if (ex1.busy or l_in.busy or fp_in.busy) = '0' then
v.e := actions.e;
v.e.valid := '0';
v.oe := e_in.oe;
v.spr_select := e_in.spr_select;
v.pmu_spr_num := e_in.insn(20 downto 16);
v.mul_select := e_in.sub_select(1 downto 0);
v.se := side_effect_init;
v.ramspr_wraddr := e_in.ramspr_wraddr;
v.ramspr_odd_data := actions.ramspr_odd_data;
end if;
lv := Execute1ToLoadstore1Init;
fv := Execute1ToFPUInit;
x_to_multiply.valid <= '0';
x_to_mult_32s.valid <= '0';
x_to_divider.valid <= '0';
v.ext_interrupt := '0';
v.taken_branch_event := '0';
v.br_mispredict := '0';
v.busy := '0';
bypass_valid := '0';
irq_valid := ex1.msr(MSR_EE) and (pmu_to_x.intr or ctrl.dec(63) or ext_irq_in);
-- 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';
do_popcnt <= '1' when e_in.insn_type = OP_POPCNT else '0';
if valid_in = '1' then
v.prev_op := e_in.insn_type;
end if;
-- Determine if there is any interrupt to be taken
-- before/instead of executing this instruction
exception := valid_in and actions.exception;
if valid_in = '1' and e_in.second = '0' then
if HAS_FPU and ex1.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 := (others => '0');
v.e.srr1(47 - 43) := '1';
v.e.srr1(47 - 47) := '1';
elsif ex1.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 := (others => '0');
v.e.srr1(47 - 33) := '1';
if ex1.prev_op = OP_LOAD or ex1.prev_op = OP_ICBI or ex1.prev_op = OP_ICBT or
ex1.prev_op = OP_DCBT or ex1.prev_op = OP_DCBST or ex1.prev_op = OP_DCBF then
v.e.srr1(47 - 35) := '1';
elsif ex1.prev_op = OP_STORE or ex1.prev_op = OP_DCBZ or
ex1.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.
if pmu_to_x.intr = '1' then
v.e.intr_vec := 16#f00#;
report "IRQ valid: PMU";
elsif ctrl.dec(63) = '1' then
v.e.intr_vec := 16#900#;
report "IRQ valid: DEC";
elsif ext_irq_in = '1' then
v.e.intr_vec := 16#500#;
report "IRQ valid: External";
v.ext_interrupt := '1';
end if;
v.e.srr1 := (others => '0');
exception := '1';
end if;
end if;
v.no_instr_avail := not (e_in.valid or l_in.busy or ex1.busy or fp_in.busy);
go := valid_in and not exception;
v.instr_dispatch := go;
if go = '1' then
v.se := actions.se;
v.e.valid := actions.complete;
bypass_valid := actions.bypass_valid;
v.taken_branch_event := actions.take_branch;
v.trace_next := actions.do_trace;
v.fp_exception_next := actions.fp_intr;
v.res2_sel := actions.res2_sel;
v.msr := actions.new_msr;
x_to_multiply.valid <= actions.start_mul;
x_to_mult_32s.valid <= actions.se.mult_32s;
v.mul_in_progress := actions.start_mul;
x_to_divider.valid <= actions.start_div;
v.div_in_progress := actions.start_div;
v.br_mispredict := v.e.redirect and actions.direct_branch;
exception := actions.trap;
if actions.advance_nia = '1' then
v.e.last_nia := next_nia;
end if;
-- Go busy while division is happening because the
-- divider is not pipelined. Also go busy while a
-- multiply is happening in order to stop following
-- instructions from using the wrong XER value
-- (and for simplicity in the OE=0 case).
v.busy := actions.start_div or actions.start_mul;
-- instruction for other units, i.e. LDST
if e_in.unit = LDST then
lv.valid := '1';
end if;
if HAS_FPU and e_in.unit = FPU then
fv.valid := '1';
end if;
end if;
if not HAS_FPU and ex1.div_in_progress = '1' then
v.div_in_progress := not divider_to_x.valid;
v.busy := not divider_to_x.valid;
if divider_to_x.valid = '1' and ex1.oe = '1' then
v.e.xerc.ov := divider_to_x.overflow;
v.e.xerc.ov32 := divider_to_x.overflow;
if divider_to_x.overflow = '1' then
v.e.xerc.so := '1';
end if;
end if;
v.e.valid := divider_to_x.valid;
v.e.write_data := alu_result;
bypass_valid := v.e.valid;
end if;
if ex1.mul_in_progress = '1' then
v.mul_in_progress := not multiply_to_x.valid;
v.mul_finish := multiply_to_x.valid and ex1.oe;
v.e.valid := multiply_to_x.valid and not ex1.oe;
v.busy := not v.e.valid;
v.e.write_data := alu_result;
bypass_valid := v.e.valid;
end if;
if ex1.mul_finish = '1' then
v.mul_finish := '0';
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 v.e.write_xerc_enable = '1' and v.e.valid = '1' then
v.xerc := v.e.xerc;
v.xerc_valid := '1';
end if;
if (ex1.busy or l_in.busy or fp_in.busy) = '0' then
v.e.interrupt := exception;
end if;
if v.e.valid = '0' then
v.e.redirect := '0';
v.e.br_last := '0';
end if;
if flush_in = '1' then
v.e.valid := '0';
v.e.interrupt := '0';
v.e.redirect := '0';
v.e.br_last := '0';
v.busy := '0';
v.div_in_progress := '0';
v.mul_in_progress := '0';
v.mul_finish := '0';
v.xerc_valid := '0';
end if;
if flush_in = '1' or interrupt_in.intr = '1' then
v.msr := ctrl_tmp.msr;
end if;
if interrupt_in.intr = '1' then
v.trace_next := '0';
v.fp_exception_next := '0';
end if;
bypass_data.tag.valid <= v.e.write_enable and bypass_valid;
bypass_data.tag.tag <= v.e.instr_tag.tag;
bypass_data.data <= alu_result;
bypass_cr_data.tag.valid <= v.e.write_cr_enable and bypass_valid;
bypass_cr_data.tag.tag <= v.e.instr_tag.tag;
bypass_cr_data.data <= v.e.write_cr_data;
-- Outputs to loadstore1 (async)
lv.op := e_in.insn_type;
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 ex1.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;
-- invert_a field is overloaded for load/store instructions
-- to mark l*cix and st*cix
lv.ci := e_in.invert_a;
lv.virt_mode := ex1.msr(MSR_DR);
lv.priv_mode := not ex1.msr(MSR_PR);
lv.mode_32bit := not ex1.msr(MSR_SF);
lv.is_32bit := e_in.is_32bit;
lv.repeat := e_in.repeat;
lv.second := e_in.second;
lv.e2stall := fp_in.f2stall;
-- Outputs to FPU
fv.op := e_in.insn_type;
fv.insn := e_in.insn;
fv.itag := e_in.instr_tag;
fv.single := e_in.is_32bit;
fv.is_signed := e_in.is_signed;
fv.fe_mode := ex1.msr(MSR_FE0) & ex1.msr(MSR_FE1);
fv.fra := a_in;
fv.frb := b_in;
fv.frc := c_in;
fv.valid_a := e_in.reg_valid1;
fv.valid_b := e_in.reg_valid2;
fv.valid_c := e_in.reg_valid3;
fv.frt := e_in.write_reg;
fv.rc := e_in.rc;
fv.out_cr := e_in.output_cr;
fv.m32b := not ex1.msr(MSR_SF);
fv.oe := e_in.oe;
fv.xerc := xerc_in;
fv.stall := l_in.l2stall;
-- Update registers
ex1in <= v;
-- update outputs
l_out <= lv;
fp_out <= fv;
irq_valid_log <= irq_valid;
end process;
-- Slow SPR read mux
with ex1.spr_select.sel select spr_result <=
ctrl.tb when SPRSEL_TB,
32x"0" & ctrl.tb(63 downto 32) when SPRSEL_TBU,
ctrl.dec when SPRSEL_DEC,
32x"0" & PVR_MICROWATT when SPRSEL_PVR,
log_wr_addr & ex2.log_addr_spr when SPRSEL_LOGA,
log_rd_data when SPRSEL_LOGD,
ctrl.cfar when SPRSEL_CFAR,
assemble_xer(ex1.e.xerc, ctrl.xer_low) when others;
stage2_stall <= l_in.l2stall or fp_in.f2stall;
-- Second execute stage control
execute2_1: process(all)
variable v : reg_stage2_type;
variable bypass_valid : std_ulogic;
variable rcresult : std_ulogic_vector(63 downto 0);
variable sprres : std_ulogic_vector(63 downto 0);
variable ex_result : std_ulogic_vector(63 downto 0);
variable cr_res : std_ulogic_vector(31 downto 0);
variable cr_mask : std_ulogic_vector(7 downto 0);
variable sign, zero : std_ulogic;
variable rcnz_hi, rcnz_lo : std_ulogic;
begin
v := ex2;
if stage2_stall = '0' then
v.e := ex1.e;
v.se := ex1.se;
v.ext_interrupt := ex1.ext_interrupt;
v.taken_branch_event := ex1.taken_branch_event;
v.br_mispredict := ex1.br_mispredict;
end if;
if ex1.se.mult_32s = '1' and ex1.oe = '1' then
v.e.xerc.ov := mult_32s_to_x.overflow;
v.e.xerc.ov32 := mult_32s_to_x.overflow;
if mult_32s_to_x.overflow = '1' then
v.e.xerc.so := '1';
end if;
end if;
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);
x_to_pmu.mfspr <= '0';
x_to_pmu.mtspr <= '0';
x_to_pmu.tbbits(3) <= ctrl.tb(63 - 47);
x_to_pmu.tbbits(2) <= ctrl.tb(63 - 51);
x_to_pmu.tbbits(1) <= ctrl.tb(63 - 55);
x_to_pmu.tbbits(0) <= ctrl.tb(63 - 63);
x_to_pmu.pmm_msr <= ctrl.msr(MSR_PMM);
x_to_pmu.pr_msr <= ctrl.msr(MSR_PR);
if v.e.valid = '0' or flush_in = '1' then
v.e.write_enable := '0';
v.e.write_cr_enable := '0';
v.e.write_xerc_enable := '0';
v.e.redirect := '0';
v.e.br_last := '0';
v.taken_branch_event := '0';
v.br_mispredict := '0';
end if;
if flush_in = '1' then
v.e.valid := '0';
v.e.interrupt := '0';
v.se := side_effect_init;
v.ext_interrupt := '0';
end if;
-- This is split like this because mfspr doesn't have an Rc bit,
-- and we don't want the zero-detect logic to be after the
-- SPR mux for timing reasons.
if ex1.se.mult_32s = '1' then
if ex1.res2_sel(0) = '0' then
rcresult := mult_32s_to_x.result(63 downto 0);
else
rcresult := mult_32s_to_x.result(63 downto 32) &
mult_32s_to_x.result(63 downto 32);
end if;
elsif ex1.res2_sel(0) = '0' then
rcresult := ex1.e.write_data;
else
rcresult := countbits_result;
end if;
if ex1.res2_sel(0) = '0' then
sprres := spr_result;
else
sprres := pmu_to_x.spr_val;
end if;
if ex1.res2_sel(1) = '0' then
ex_result := rcresult;
else
ex_result := sprres;
end if;
cr_res := ex1.e.write_cr_data;
cr_mask := ex1.e.write_cr_mask;
if ex1.e.rc = '1' and ex1.e.write_enable = '1' then
rcnz_lo := or (rcresult(31 downto 0));
if ex1.e.mode_32bit = '0' then
rcnz_hi := or (rcresult(63 downto 32));
zero := not (rcnz_hi or rcnz_lo);
sign := ex_result(63);
else
zero := not rcnz_lo;
sign := ex_result(31);
end if;
cr_res(31) := sign;
cr_res(30) := not (sign or zero);
cr_res(29) := zero;
cr_res(28) := v.e.xerc.so;
cr_mask(7) := '1';
end if;
if stage2_stall = '0' then
v.e.write_data := ex_result;
v.e.write_cr_data := cr_res;
v.e.write_cr_mask := cr_mask;
if ex1.e.rc = '1' and ex1.e.write_enable = '1' and v.e.valid = '1' then
v.e.write_cr_enable := '1';
end if;
if ex1.se.write_msr = '1' then
ctrl_tmp.msr <= ex1.msr;
end if;
if ex1.se.write_xerlow = '1' then
ctrl_tmp.xer_low <= ex1.e.write_data(17 downto 0);
end if;
if ex1.se.write_dec = '1' then
ctrl_tmp.dec <= ex1.e.write_data;
end if;
if ex1.se.write_cfar = '1' then
ctrl_tmp.cfar <= ex1.e.last_nia;
end if;
if ex1.se.write_loga = '1' then
v.log_addr_spr := ex1.e.write_data(31 downto 0);
elsif ex1.se.inc_loga = '1' then
v.log_addr_spr := std_ulogic_vector(unsigned(ex2.log_addr_spr) + 1);
end if;
x_to_pmu.mtspr <= ex1.se.write_pmuspr;
end if;
if interrupt_in.intr = '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';
end if;
bypass_valid := ex1.e.valid;
if stage2_stall = '1' and ex1.res2_sel(1) = '1' then
bypass_valid := '0';
end if;
bypass2_data.tag.valid <= ex1.e.write_enable and bypass_valid;
bypass2_data.tag.tag <= ex1.e.instr_tag.tag;
bypass2_data.data <= ex_result;
bypass2_cr_data.tag.valid <= (ex1.e.write_cr_enable or (ex1.e.rc and ex1.e.write_enable))
and bypass_valid;
bypass2_cr_data.tag.tag <= ex1.e.instr_tag.tag;
bypass2_cr_data.data <= cr_res;
-- Update registers
ex2in <= v;
-- update outputs
e_out <= ex2.e;
e_out.msr <= msr_copy(ctrl.msr);
terminate_out <= ex2.se.terminate;
icache_inval <= ex2.se.icache_inval;
exception_log <= v.e.interrupt;
end process;
sim_dump_test: if SIM generate
dump_exregs: process(all)
variable xer : std_ulogic_vector(63 downto 0);
begin
if sim_dump = '1' then
report "LR " & to_hstring(even_sprs(to_integer(RAMSPR_LR)));
report "CTR " & to_hstring(odd_sprs(to_integer(RAMSPR_CTR)));
sim_dump_done <= '1';
else
sim_dump_done <= '0';
end if;
end process;
end generate;
-- Keep GHDL synthesis happy
sim_dump_test_synth: if not SIM generate
sim_dump_done <= '0';
end generate;
e1_log: if LOG_LENGTH > 0 generate
signal log_data : std_ulogic_vector(11 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.intr &
ex2.e.write_enable &
ex2.e.valid &
(ex2.e.redirect or ex2.e.interrupt) &
ex1.busy &
flush_in;
end if;
end process;
log_out <= log_data;
end generate;
end architecture behaviour;