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Merge pull request #105 from paulusmack/writeback

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Writeback
pull/110/head
Anton Blanchard 5 years ago committed by GitHub
parent 640af89e72 57b200d6cb
commit 4433118c91
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GPG Key ID: 4AEE18F83AFDEB23
15 changed files with 190 additions and 239 deletions
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9
Makefile
Unescape Escape View File

@ -17,7 +17,7 @@ common.o: decode_types.o
control.o: gpr_hazard.o cr_hazard.o
sim_jtag.o: sim_jtag_socket.o
core_tb.o: common.o wishbone_types.o core.o soc.o sim_jtag.o
core.o: common.o wishbone_types.o fetch1.o fetch2.o icache.o decode1.o decode2.o register_file.o cr_file.o execute1.o execute2.o loadstore1.o loadstore2.o multiply.o writeback.o core_debug.o divider.o
core.o: common.o wishbone_types.o fetch1.o fetch2.o icache.o decode1.o decode2.o register_file.o cr_file.o execute1.o loadstore1.o loadstore2.o multiply.o writeback.o core_debug.o divider.o
core_debug.o: common.o
countzero.o:
countzero_tb.o: common.o glibc_random.o countzero.o
@ -27,7 +27,6 @@ decode1.o: common.o decode_types.o
decode2.o: decode_types.o common.o helpers.o insn_helpers.o control.o
decode_types.o:
execute1.o: decode_types.o common.o helpers.o crhelpers.o insn_helpers.o ppc_fx_insns.o rotator.o logical.o countzero.o
execute2.o: common.o crhelpers.o ppc_fx_insns.o
fetch1.o: common.o
fetch2.o: common.o wishbone_types.o
glibc_random_helpers.o:
@ -43,9 +42,9 @@ loadstore1.o: common.o helpers.o
loadstore2.o: common.o helpers.o wishbone_types.o
logical.o: decode_types.o
multiply_tb.o: decode_types.o common.o glibc_random.o ppc_fx_insns.o multiply.o
multiply.o: common.o decode_types.o ppc_fx_insns.o crhelpers.o
multiply.o: common.o decode_types.o
divider_tb.o: decode_types.o common.o glibc_random.o ppc_fx_insns.o divider.o
divider.o: common.o decode_types.o crhelpers.o
divider.o: common.o decode_types.o
ppc_fx_insns.o: helpers.o
register_file.o: common.o
rotator.o: common.o
@ -58,7 +57,7 @@ sim_uart.o: wishbone_types.o sim_console.o
soc.o: common.o wishbone_types.o core.o wishbone_arbiter.o sim_uart.o simple_ram_behavioural.o dmi_dtm_xilinx.o wishbone_debug_master.o
wishbone_arbiter.o: wishbone_types.o
wishbone_types.o:
writeback.o: common.o
writeback.o: common.o crhelpers.o
dmi_dtm_tb.o: dmi_dtm_xilinx.o wishbone_debug_master.o
dmi_dtm_xilinx.o: wishbone_types.o sim-unisim/unisim_vcomponents.o
wishbone_debug_master.o: wishbone_types.o

37
common.vhdl
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@ -64,6 +64,7 @@ package common is
is_32bit: std_ulogic;
is_signed: std_ulogic;
insn: std_ulogic_vector(31 downto 0);
data_len: std_ulogic_vector(3 downto 0);
end record;
constant Decode2ToExecute1Init : Decode2ToExecute1Type :=
(valid => '0', insn_type => OP_ILLEGAL, lr => '0', rc => '0', invert_a => '0',
@ -155,31 +156,27 @@ package common is
write_enable: std_ulogic;
write_reg : std_ulogic_vector(4 downto 0);
write_data : std_ulogic_vector(63 downto 0);
write_len : std_ulogic_vector(3 downto 0);
write_shift : std_ulogic_vector(2 downto 0);
sign_extend : std_ulogic;
byte_reverse : std_ulogic;
second_word : std_ulogic;
end record;
constant Loadstore2ToWritebackInit : Loadstore2ToWritebackType := (valid => '0', write_enable => '0', others => (others => '0'));
constant Loadstore2ToWritebackInit : Loadstore2ToWritebackType := (valid => '0', write_enable => '0', sign_extend => '0', byte_reverse => '0', second_word => '0', others => (others => '0'));

type Execute1ToExecute2Type is record
type Execute1ToWritebackType is record
valid: std_ulogic;
write_enable : std_ulogic;
write_reg: std_ulogic_vector(4 downto 0);
write_data: std_ulogic_vector(63 downto 0);
write_cr_enable : std_ulogic;
write_cr_mask : std_ulogic_vector(7 downto 0);
write_cr_data : std_ulogic_vector(31 downto 0);
rc : std_ulogic;
end record;
constant Execute1ToExecute2Init : Execute1ToExecute2Type := (valid => '0', write_enable => '0', write_cr_enable => '0', rc => '0', others => (others => '0'));

type Execute2ToWritebackType is record
valid: std_ulogic;
write_enable : std_ulogic;
write_reg: std_ulogic_vector(4 downto 0);
write_data: std_ulogic_vector(63 downto 0);
write_len : std_ulogic_vector(3 downto 0);
write_cr_enable : std_ulogic;
write_cr_mask : std_ulogic_vector(7 downto 0);
write_cr_data : std_ulogic_vector(31 downto 0);
sign_extend: std_ulogic;
end record;
constant Execute2ToWritebackInit : Execute2ToWritebackType := (valid => '0', write_enable => '0', write_cr_enable => '0', others => (others => '0'));
constant Execute1ToWritebackInit : Execute1ToWritebackType := (valid => '0', rc => '0', write_enable => '0', write_cr_enable => '0', sign_extend => '0', others => (others => '0'));

type MultiplyToWritebackType is record
valid: std_ulogic;
@ -187,11 +184,9 @@ package common is
write_reg_enable : std_ulogic;
write_reg_nr: std_ulogic_vector(4 downto 0);
write_reg_data: std_ulogic_vector(63 downto 0);
write_cr_enable: std_ulogic;
write_cr_mask: std_ulogic_vector(7 downto 0);
write_cr_data: std_ulogic_vector(31 downto 0);
rc: std_ulogic;
end record;
constant MultiplyToWritebackInit : MultiplyToWritebackType := (valid => '0', write_reg_enable => '0', write_cr_enable => '0', others => (others => '0'));
constant MultiplyToWritebackInit : MultiplyToWritebackType := (valid => '0', write_reg_enable => '0', rc => '0', others => (others => '0'));

type DividerToWritebackType is record
valid: std_ulogic;
@ -199,11 +194,9 @@ package common is
write_reg_enable : std_ulogic;
write_reg_nr: std_ulogic_vector(4 downto 0);
write_reg_data: std_ulogic_vector(63 downto 0);
write_cr_enable: std_ulogic;
write_cr_mask: std_ulogic_vector(7 downto 0);
write_cr_data: std_ulogic_vector(31 downto 0);
rc: std_ulogic;
end record;
constant DividerToWritebackInit : DividerToWritebackType := (valid => '0', write_reg_enable => '0', write_cr_enable => '0', others => (others => '0'));
constant DividerToWritebackInit : DividerToWritebackType := (valid => '0', write_reg_enable => '0', rc => '0', others => (others => '0'));

type WritebackToRegisterFileType is record
write_reg : std_ulogic_vector(4 downto 0);

14
core.vhdl
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@ -54,8 +54,7 @@ architecture behave of core is
signal writeback_to_cr_file: WritebackToCrFileType;

-- execute signals
signal execute1_to_execute2: Execute1ToExecute2Type;
signal execute2_to_writeback: Execute2ToWritebackType;
signal execute1_to_writeback: Execute1ToWritebackType;
signal execute1_to_fetch1: Execute1ToFetch1Type;

-- load store signals
@ -204,17 +203,10 @@ begin
flush_out => flush,
e_in => decode2_to_execute1,
f_out => execute1_to_fetch1,
e_out => execute1_to_execute2,
e_out => execute1_to_writeback,
terminate_out => terminate
);

execute2_0: entity work.execute2
port map (
clk => clk,
e_in => execute1_to_execute2,
e_out => execute2_to_writeback
);

loadstore1_0: entity work.loadstore1
port map (
clk => clk,
@ -249,7 +241,7 @@ begin
writeback_0: entity work.writeback
port map (
clk => clk,
e_in => execute2_to_writeback,
e_in => execute1_to_writeback,
l_in => loadstore2_to_writeback,
m_in => multiply_to_writeback,
d_in => divider_to_writeback,

6
decode1.vhdl
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@ -164,9 +164,9 @@ architecture behaviour of decode1 is
2#0111101001# => (DIV, OP_DIV, RA, RB, NONE, RT, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'), -- divd
2#0111101011# => (DIV, OP_DIV, RA, RB, NONE, RT, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'), -- divw
2#0100011100# => (ALU, OP_XOR, NONE, RB, RS, RA, '0', '0', '0', '1', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- eqv
2#1110111010# => (ALU, OP_EXTSB, NONE, NONE, RS, RA, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- extsb
2#1110011010# => (ALU, OP_EXTSH, NONE, NONE, RS, RA, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- extsh
2#1111011010# => (ALU, OP_EXTSW, NONE, NONE, RS, RA, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- extsw
2#1110111010# => (ALU, OP_EXTS, NONE, NONE, RS, RA, '0', '0', '0', '0', ZERO, '0', is1B, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- extsb
2#1110011010# => (ALU, OP_EXTS, NONE, NONE, RS, RA, '0', '0', '0', '0', ZERO, '0', is2B, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- extsh
2#1111011010# => (ALU, OP_EXTS, NONE, NONE, RS, RA, '0', '0', '0', '0', ZERO, '0', is4B, '0', '0', '0', '0', '0', '0', RC, '0', '0'), -- extsw
-- 2#110111101-# extswsli
2#1111010110# => (ALU, OP_NOP, NONE, NONE, NONE, NONE, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), -- icbi
2#0000010110# => (ALU, OP_NOP, NONE, NONE, NONE, NONE, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), -- icbt

29
decode2.vhdl
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@ -208,6 +208,7 @@ begin
variable decoded_reg_b : decode_input_reg_t;
variable decoded_reg_c : decode_input_reg_t;
variable signed_division: std_ulogic;
variable length : std_ulogic_vector(3 downto 0);
begin
v := r;

@ -231,6 +232,19 @@ begin
r_out.read2_enable <= decoded_reg_b.reg_valid;
r_out.read3_enable <= decoded_reg_c.reg_valid;

case d_in.decode.length is
when is1B =>
length := "0001";
when is2B =>
length := "0010";
when is4B =>
length := "0100";
when is8B =>
length := "1000";
when NONE =>
length := "0000";
end case;

-- execute unit
v.e.nia := d_in.nia;
v.e.insn_type := d_in.decode.insn_type;
@ -252,6 +266,7 @@ begin
v.e.lr := insn_lk(d_in.insn);
end if;
v.e.insn := d_in.insn;
v.e.data_len := length;

-- multiply unit
v.m.insn_type := d_in.decode.insn_type;
@ -336,19 +351,7 @@ begin
v.l.load := '0';
end if;

case d_in.decode.length is
when is1B =>
v.l.length := "0001";
when is2B =>
v.l.length := "0010";
when is4B =>
v.l.length := "0100";
when is8B =>
v.l.length := "1000";
when NONE =>
v.l.length := "0000";
end case;

v.l.length := length;
v.l.byte_reverse := d_in.decode.byte_reverse;
v.l.sign_extend := d_in.decode.sign_extend;
v.l.update := d_in.decode.update;

2
decode_types.vhdl
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@ -8,7 +8,7 @@ package decode_types is
OP_CNTZ, OP_CRAND,
OP_CRANDC, OP_CREQV, OP_CRNAND, OP_CRNOR, OP_CROR, OP_CRORC,
OP_CRXOR, OP_DARN, OP_DCBF, OP_DCBST, OP_DCBT, OP_DCBTST,
OP_DCBZ, OP_DIV, OP_EXTSB, OP_EXTSH, OP_EXTSW,
OP_DCBZ, OP_DIV, OP_EXTS,
OP_EXTSWSLI, OP_ICBI, OP_ICBT, OP_ISEL, OP_ISYNC,
OP_LOAD, OP_STORE, OP_MADDHD, OP_MADDHDU, OP_MADDLD, OP_MCRF,
OP_MCRXR, OP_MCRXRX, OP_MFCR, OP_MFSPR, OP_MOD,

15
divider.vhdl
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@ -5,7 +5,6 @@ use ieee.numeric_std.all;
library work;
use work.common.all;
use work.decode_types.all;
use work.crhelpers.all;

entity divider is
port (
@ -37,7 +36,6 @@ architecture behaviour of divider is
signal overflow : std_ulogic;
signal ovf32 : std_ulogic;
signal did_ovf : std_ulogic;
signal cr_data : std_ulogic_vector(2 downto 0);

begin
divider_0: process(clk)
@ -114,7 +112,7 @@ begin
divider_1: process(all)
begin
d_out.write_reg_nr <= write_reg;
d_out.write_cr_mask <= num_to_fxm(0);
d_out.rc <= rc;

if is_modulus = '1' then
result <= dend(128 downto 65);
@ -144,29 +142,18 @@ begin
else
oresult <= sresult;
end if;

if (did_ovf = '1') or (or (sresult) = '0') then
cr_data <= "001";
elsif (sresult(63) = '1') and not ((is_32bit = '1') and (is_modulus = '0')) then
cr_data <= "100";
else
cr_data <= "010";
end if;
end process;

divider_out: process(clk)
begin
if rising_edge(clk) then
d_out.write_reg_data <= oresult;
d_out.write_cr_data <= cr_data & '0' & x"0000000";
if count = "1000000" then
d_out.valid <= '1';
d_out.write_reg_enable <= '1';
d_out.write_cr_enable <= rc;
else
d_out.valid <= '0';
d_out.write_reg_enable <= '0';
d_out.write_cr_enable <= '0';
end if;
end if;
end process;

30
divider_tb.vhdl
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@ -68,7 +68,7 @@ begin
assert d2.write_reg_enable = '1';
assert d2.write_reg_nr = "10001";
assert d2.write_reg_data = x"000000000000f001" report "result " & to_hstring(d2.write_reg_data);
assert d2.write_cr_enable = '0';
assert d2.rc = '0';

wait for clk_period;
assert d2.valid = '0' report "valid";
@ -92,9 +92,7 @@ begin
assert d2.write_reg_enable = '1';
assert d2.write_reg_nr = "10001";
assert d2.write_reg_data = x"000000000000f001" report "result " & to_hstring(d2.write_reg_data);
assert d2.write_cr_enable = '1';
assert d2.write_cr_mask = "10000000";
assert d2.write_cr_data = x"40000000" report "cr data is " & to_hstring(d2.write_cr_data);
assert d2.rc = '1';

wait for clk_period;
assert d2.valid = '0';
@ -129,8 +127,6 @@ begin
end if;
assert to_hstring(behave_rt) = to_hstring(d2.write_reg_data)
report "bad divd expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divd";
end loop;
end loop;
end loop;
@ -165,8 +161,6 @@ begin
end if;
assert to_hstring(behave_rt) = to_hstring(d2.write_reg_data)
report "bad divdu expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divdu";
end loop;
end loop;
end loop;
@ -207,8 +201,6 @@ begin
end if;
assert to_hstring(behave_rt) = to_hstring(d2.write_reg_data)
report "bad divde expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data) & " for ra = " & to_hstring(ra) & " rb = " & to_hstring(rb);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divde";
end loop;
end loop;
end loop;
@ -246,8 +238,6 @@ begin
end if;
assert to_hstring(behave_rt) = to_hstring(d2.write_reg_data)
report "bad divdeu expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data) & " for ra = " & to_hstring(ra) & " rb = " & to_hstring(rb);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divdeu";
end loop;
end loop;
end loop;
@ -284,8 +274,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad divw expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divw";
end loop;
end loop;
end loop;
@ -322,8 +310,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad divwu expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divwu";
end loop;
end loop;
end loop;
@ -363,8 +349,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad divwe expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data) & " for ra = " & to_hstring(ra) & " rb = " & to_hstring(rb);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divwe";
end if;
end loop;
end loop;
@ -402,8 +386,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad divweu expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data) & " for ra = " & to_hstring(ra) & " rb = " & to_hstring(rb);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divweu";
end loop;
end loop;
end loop;
@ -441,8 +423,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad modsd expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for modsd";
end loop;
end loop;
end loop;
@ -480,8 +460,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad modud expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for modud";
end loop;
end loop;
end loop;
@ -524,8 +502,6 @@ begin
end if;
assert behave_rt = d2.write_reg_data
report "bad modsw expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for modsw";
end loop;
end loop;
end loop;
@ -563,8 +539,6 @@ begin
end if;
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
report "bad moduw expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for moduw";
end loop;
end loop;
end loop;

20
execute1.vhdl
Unescape Escape View File

@ -25,7 +25,7 @@ entity execute1 is
-- asynchronous
f_out : out Execute1ToFetch1Type;

e_out : out Execute1ToExecute2Type;
e_out : out Execute1ToWritebackType;

terminate_out : out std_ulogic
);
@ -34,7 +34,7 @@ end entity execute1;
architecture behaviour of execute1 is
type reg_type is record
--f : Execute1ToFetch1Type;
e : Execute1ToExecute2Type;
e : Execute1ToWritebackType;
end record;

signal r, rin : reg_type;
@ -124,7 +124,7 @@ begin
newcrf := (others => '0');

v := r;
v.e := Execute1ToExecute2Init;
v.e := Execute1ToWritebackInit;
--v.f := Execute1ToFetch1TypeInit;

ctrl_tmp <= ctrl;
@ -143,6 +143,8 @@ begin

v.e.valid := '1';
v.e.write_reg := e_in.write_reg;
v.e.write_len := x"8";
v.e.sign_extend := '0';

case_0: case e_in.insn_type is

@ -230,14 +232,10 @@ begin
when OP_CNTZ =>
result := countzero_result;
result_en := 1;
when OP_EXTSB =>
result := ppc_extsb(e_in.read_data3);
result_en := 1;
when OP_EXTSH =>
result := ppc_extsh(e_in.read_data3);
result_en := 1;
when OP_EXTSW =>
result := ppc_extsw(e_in.read_data3);
when OP_EXTS =>
v.e.write_len := e_in.data_len;
v.e.sign_extend := '1';
result := e_in.read_data3;
result_en := 1;
when OP_ISEL =>
crnum := to_integer(unsigned(insn_bc(e_in.insn)));

57
execute2.vhdl
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@ -1,57 +0,0 @@
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

library work;
use work.common.all;
use work.crhelpers.all;
use work.ppc_fx_insns.all;

-- 2 cycle ALU
-- We handle rc form instructions here

entity execute2 is
port (
clk : in std_ulogic;

e_in : in Execute1ToExecute2Type;
e_out : out Execute2ToWritebackType
);
end execute2;

architecture behave of execute2 is
signal r, rin : Execute2ToWritebackType;
begin
execute2_0: process(clk)
begin
if rising_edge(clk) then
r <= rin;
end if;
end process;

execute2_1: process(all)
variable v : Execute2ToWritebackType;
begin
v := rin;

v.valid := e_in.valid;
v.write_enable := e_in.write_enable;
v.write_reg := e_in.write_reg;
v.write_data := e_in.write_data;
v.write_cr_enable := e_in.write_cr_enable;
v.write_cr_mask := e_in.write_cr_mask;
v.write_cr_data := e_in.write_cr_data;

if e_in.valid = '1' and e_in.rc = '1' then
v.write_cr_enable := '1';
v.write_cr_mask := num_to_fxm(0);
v.write_cr_data := ppc_cmpi('1', e_in.write_data, x"0000") & x"0000000";
end if;

-- Update registers
rin <= v;

-- Update outputs
e_out <= r;
end process;
end;

56
loadstore2.vhdl
Unescape Escape View File

@ -26,9 +26,6 @@ architecture behave of loadstore2 is
signal l_saved : Loadstore1ToLoadstore2Type;
signal w_tmp : Loadstore2ToWritebackType;
signal m_tmp : wishbone_master_out;
signal read_data : std_ulogic_vector(63 downto 0);
signal read_data_shift : std_ulogic_vector(2 downto 0);
signal sign_extend_byte_reverse: std_ulogic_vector(1 downto 0);
signal dlength : std_ulogic_vector(3 downto 0);

type state_t is (IDLE, WAITING_FOR_READ_ACK, WAITING_FOR_WRITE_ACK);
@ -61,37 +58,6 @@ architecture behave of loadstore2 is
end function wishbone_data_sel;
begin

loadstore2_1: process(all)
variable tmp : std_ulogic_vector(63 downto 0);
variable data : std_ulogic_vector(63 downto 0);
begin
tmp := std_logic_vector(shift_right(unsigned(read_data), to_integer(unsigned(read_data_shift)) * 8));
data := (others => '0');
case to_integer(unsigned(dlength)) is
when 0 =>
when 1 =>
data(7 downto 0) := tmp(7 downto 0);
when 2 =>
data(15 downto 0) := tmp(15 downto 0);
when 4 =>
data(31 downto 0) := tmp(31 downto 0);
when 8 =>
data(63 downto 0) := tmp(63 downto 0);
when others =>
assert false report "invalid length" severity failure;
data(63 downto 0) := tmp(63 downto 0);
end case;

case sign_extend_byte_reverse is
when "10" =>
w_tmp.write_data <= sign_extend(data, to_integer(unsigned(l_saved.length)));
when "01" =>
w_tmp.write_data <= byte_reverse(data, to_integer(unsigned(l_saved.length)));
when others =>
w_tmp.write_data <= data;
end case;
end process;

w_out <= w_tmp;
m_out <= m_tmp;

@ -102,11 +68,13 @@ begin
w_tmp.valid <= '0';
w_tmp.write_enable <= '0';
w_tmp.write_reg <= (others => '0');
w_tmp.write_len <= "1000";
w_tmp.write_shift <= "000";
w_tmp.sign_extend <= '0';
w_tmp.byte_reverse <= '0';
w_tmp.second_word <= '0';

l_saved <= l_saved;
read_data_shift <= "000";
sign_extend_byte_reverse <= "00";
dlength <= "1000";

case_0: case state is
when IDLE =>
@ -131,7 +99,7 @@ begin
if l_in.update = '1' then
w_tmp.write_enable <= '1';
w_tmp.write_reg <= l_in.update_reg;
read_data <= l_in.addr;
w_tmp.write_data <= l_in.addr;
end if;

state <= WAITING_FOR_READ_ACK;
@ -148,15 +116,15 @@ begin

when WAITING_FOR_READ_ACK =>
if m_in.ack = '1' then
read_data <= m_in.dat;
read_data_shift <= l_saved.addr(2 downto 0);
dlength <= l_saved.length;
sign_extend_byte_reverse <= l_saved.sign_extend & l_saved.byte_reverse;

-- write data to register file
w_tmp.valid <= '1';
w_tmp.write_enable <= '1';
w_tmp.write_data <= m_in.dat;
w_tmp.write_reg <= l_saved.write_reg;
w_tmp.write_len <= l_saved.length;
w_tmp.write_shift <= l_saved.addr(2 downto 0);
w_tmp.sign_extend <= l_saved.sign_extend;
w_tmp.byte_reverse <= l_saved.byte_reverse;

m_tmp <= wishbone_master_out_init;
state <= IDLE;
@ -168,7 +136,7 @@ begin
if l_saved.update = '1' then
w_tmp.write_enable <= '1';
w_tmp.write_reg <= l_saved.update_reg;
read_data <= l_saved.addr;
w_tmp.write_data <= l_saved.addr;
end if;

m_tmp <= wishbone_master_out_init;

1
microwatt.core
Unescape Escape View File

@ -24,7 +24,6 @@ filesets:
- cr_hazard.vhdl
- control.vhdl
- execute1.vhdl
- execute2.vhdl
- loadstore1.vhdl
- loadstore2.vhdl
- multiply.vhdl

9
multiply.vhdl
Unescape Escape View File

@ -5,8 +5,6 @@ use ieee.numeric_std.all;
library work;
use work.common.all;
use work.decode_types.all;
use work.ppc_fx_insns.all;
use work.crhelpers.all;

entity multiply is
generic (
@ -88,12 +86,7 @@ begin
if v.multiply_pipeline(PIPELINE_DEPTH-1).valid = '1' then
m_out.valid <= '1';
m_out.write_reg_enable <= '1';

if v.multiply_pipeline(PIPELINE_DEPTH-1).rc = '1' then
m_out.write_cr_enable <= '1';
m_out.write_cr_mask <= num_to_fxm(0);
m_out.write_cr_data <= ppc_cmpi('1', d2, x"0000") & x"0000000";
end if;
m_out.rc <= v.multiply_pipeline(PIPELINE_DEPTH-1).rc;
end if;

rin <= v;

5
multiply_tb.vhdl
Unescape Escape View File

@ -61,7 +61,7 @@ begin
assert m2.write_reg_enable = '1';
assert m2.write_reg_nr = "10001";
assert m2.write_reg_data = x"0000000001111000";
assert m2.write_cr_enable = '0';
assert m2.rc = '0';

wait for clk_period;
assert m2.valid = '0';
@ -79,8 +79,7 @@ begin
assert m2.write_reg_enable = '1';
assert m2.write_reg_nr = "10001";
assert m2.write_reg_data = x"0000000001111000";
assert m2.write_cr_enable = '1';
assert m2.write_cr_data = x"40000000";
assert m2.rc = '1';

-- test mulld
mulld_loop : for i in 0 to 1000 loop

139
writeback.vhdl
Unescape Escape View File

@ -4,12 +4,13 @@ use ieee.numeric_std.all;

library work;
use work.common.all;
use work.crhelpers.all;

entity writeback is
port (
clk : in std_ulogic;

e_in : in Execute2ToWritebackType;
e_in : in Execute1ToWritebackType;
l_in : in Loadstore2ToWritebackType;
m_in : in MultiplyToWritebackType;
d_in : in DividerToWritebackType;
@ -22,12 +23,44 @@ entity writeback is
end entity writeback;

architecture behaviour of writeback is
subtype byte_index_t is unsigned(2 downto 0);
type permutation_t is array(0 to 7) of byte_index_t;
subtype byte_trim_t is std_ulogic_vector(1 downto 0);
type trim_ctl_t is array(0 to 7) of byte_trim_t;
type byte_sel_t is array(0 to 7) of std_ulogic;

signal data_len : unsigned(3 downto 0);
signal data_in : std_ulogic_vector(63 downto 0);
signal data_permuted : std_ulogic_vector(63 downto 0);
signal data_trimmed : std_ulogic_vector(63 downto 0);
signal data_latched : std_ulogic_vector(63 downto 0);
signal perm : permutation_t;
signal use_second : byte_sel_t;
signal byte_offset : unsigned(2 downto 0);
signal brev_lenm1 : unsigned(2 downto 0);
signal trim_ctl : trim_ctl_t;
signal rc : std_ulogic;
signal partial_write : std_ulogic;
signal sign_extend : std_ulogic;
signal negative : std_ulogic;
signal second_word : std_ulogic;
begin
writeback_0: process(clk)
begin
if rising_edge(clk) then
if partial_write = '1' then
data_latched <= data_permuted;
end if;
end if;
end process;

writeback_1: process(all)
variable x : std_ulogic_vector(0 downto 0);
variable y : std_ulogic_vector(0 downto 0);
variable z : std_ulogic_vector(0 downto 0);
variable w : std_ulogic_vector(0 downto 0);
variable j : integer;
variable k : unsigned(3 downto 0);
begin
x := "" & e_in.valid;
y := "" & l_in.valid;
@ -41,10 +74,11 @@ begin
w := "" & d_in.write_reg_enable;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z)) + to_integer(unsigned(w))) <= 1 severity failure;

x := "" & e_in.write_cr_enable;
y := "" & m_in.write_cr_enable;
z := "" & d_in.write_cr_enable;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1 severity failure;
w := "" & e_in.write_cr_enable;
x := "" & (e_in.write_enable and e_in.rc);
y := "" & (m_in.valid and m_in.rc);
z := "" & (d_in.valid and d_in.rc);
assert (to_integer(unsigned(w)) + to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1 severity failure;

w_out <= WritebackToRegisterFileInit;
c_out <= WritebackToCrFileInit;
@ -54,10 +88,22 @@ begin
complete_out <= '1';
end if;

rc <= '0';
brev_lenm1 <= "000";
byte_offset <= "000";
data_len <= x"8";
partial_write <= '0';
sign_extend <= '0';
second_word <= '0';
data_in <= (others => '0');

if e_in.write_enable = '1' then
w_out.write_reg <= e_in.write_reg;
w_out.write_data <= e_in.write_data;
data_in <= e_in.write_data;
w_out.write_enable <= '1';
data_len <= unsigned(e_in.write_len);
sign_extend <= e_in.sign_extend;
rc <= e_in.rc;
end if;

if e_in.write_cr_enable = '1' then
@ -68,32 +114,89 @@ begin

if l_in.write_enable = '1' then
w_out.write_reg <= l_in.write_reg;
w_out.write_data <= l_in.write_data;
data_in <= l_in.write_data;
data_len <= unsigned(l_in.write_len);
byte_offset <= unsigned(l_in.write_shift);
sign_extend <= l_in.sign_extend;
if l_in.byte_reverse = '1' then
brev_lenm1 <= unsigned(l_in.write_len(2 downto 0)) - 1;
end if;
w_out.write_enable <= '1';
second_word <= l_in.second_word;
if l_in.valid = '0' and (data_len + byte_offset > 8) then
partial_write <= '1';
end if;
end if;

if m_in.write_reg_enable = '1' then
w_out.write_enable <= '1';
w_out.write_reg <= m_in.write_reg_nr;
w_out.write_data <= m_in.write_reg_data;
end if;

if m_in.write_cr_enable = '1' then
c_out.write_cr_enable <= '1';
c_out.write_cr_mask <= m_in.write_cr_mask;
c_out.write_cr_data <= m_in.write_cr_data;
data_in <= m_in.write_reg_data;
rc <= m_in.rc;
end if;

if d_in.write_reg_enable = '1' then
w_out.write_enable <= '1';
w_out.write_reg <= d_in.write_reg_nr;
w_out.write_data <= d_in.write_reg_data;
data_in <= d_in.write_reg_data;
rc <= d_in.rc;
end if;

if d_in.write_cr_enable = '1' then
-- shift and byte-reverse data bytes
for i in 0 to 7 loop
k := ('0' & (to_unsigned(i, 3) xor brev_lenm1)) + ('0' & byte_offset);
perm(i) <= k(2 downto 0);
use_second(i) <= k(3);
end loop;
for i in 0 to 7 loop
j := to_integer(perm(i)) * 8;
data_permuted(i * 8 + 7 downto i * 8) <= data_in(j + 7 downto j);
end loop;

-- If the data can arrive split over two cycles, this will be correct
-- provided we don't have both sign extension and byte reversal.
negative <= (data_len(2) and data_permuted(31)) or (data_len(1) and data_permuted(15)) or
(data_len(0) and data_permuted(7));

-- trim and sign-extend
for i in 0 to 7 loop
if i < to_integer(data_len) then
if second_word = '1' then
trim_ctl(i) <= '1' & not use_second(i);
else
trim_ctl(i) <= not use_second(i) & '0';
end if;
else
trim_ctl(i) <= '0' & (negative and sign_extend);
end if;
end loop;
for i in 0 to 7 loop
case trim_ctl(i) is
when "11" =>
data_trimmed(i * 8 + 7 downto i * 8) <= data_latched(i * 8 + 7 downto i * 8);
when "10" =>
data_trimmed(i * 8 + 7 downto i * 8) <= data_permuted(i * 8 + 7 downto i * 8);
when "01" =>
data_trimmed(i * 8 + 7 downto i * 8) <= x"FF";
when others =>
data_trimmed(i * 8 + 7 downto i * 8) <= x"00";
end case;
end loop;

-- deliver to regfile
w_out.write_data <= data_trimmed;

-- test value against 0 and set CR0 if requested
if rc = '1' then
c_out.write_cr_enable <= '1';
c_out.write_cr_mask <= d_in.write_cr_mask;
c_out.write_cr_data <= d_in.write_cr_data;
c_out.write_cr_mask <= num_to_fxm(0);
if data_trimmed(63) = '1' then
c_out.write_cr_data <= x"80000000";
elsif or (data_trimmed(62 downto 0)) = '1' then
c_out.write_cr_data <= x"40000000";
else
c_out.write_cr_data <= x"20000000";
end if;
end if;
end process;
end;

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