Add a divider unit and a testbench for it

This adds a divider unit, connected to the core in much the same way
that the multiplier unit is connected.  The division algorithm is
very simple-minded, taking 64 clock cycles for any division (even
32-bit division instructions).

The decoding is simplified by making use of regularities in the
instruction encoding for div* and mod* instructions.  Instead of
having PPC_* encodings from the first-stage decoder for each of the
different div* and mod* instructions, we now just have PPC_DIV and
PPC_MOD, and the inputs to the divider that indicate what sort of
division operation to do are derived from instruction word bits.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
pull/68/head
Paul Mackerras 5 years ago
parent 6571b13308
commit d5bc6c8824

@ -2,7 +2,7 @@ GHDL=ghdl
GHDLFLAGS=--std=08 GHDLFLAGS=--std=08
CFLAGS=-O2 -Wall CFLAGS=-O2 -Wall


all = core_tb simple_ram_behavioural_tb soc_reset_tb icache_tb multiply_tb all = core_tb simple_ram_behavioural_tb soc_reset_tb icache_tb multiply_tb divider_tb
# XXX # XXX
# loadstore_tb fetch_tb # loadstore_tb fetch_tb


@ -13,7 +13,7 @@ all: $(all)


common.o: decode_types.o common.o: decode_types.o
core_tb.o: common.o core.o soc.o core_tb.o: common.o core.o soc.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.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 divider.o writeback.o
cr_file.o: common.o cr_file.o: common.o
crhelpers.o: common.o crhelpers.o: common.o
decode1.o: common.o decode_types.o decode1.o: common.o decode_types.o
@ -33,6 +33,8 @@ loadstore1.o: common.o
loadstore2.o: common.o helpers.o wishbone_types.o loadstore2.o: common.o helpers.o wishbone_types.o
multiply_tb.o: common.o glibc_random.o ppc_fx_insns.o multiply.o multiply_tb.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 ppc_fx_insns.o crhelpers.o
divider_tb.o: common.o glibc_random.o ppc_fx_insns.o divider.o
divider.o: common.o decode_types.o ppc_fx_insns.o crhelpers.o
ppc_fx_insns.o: helpers.o ppc_fx_insns.o: helpers.o
register_file.o: common.o register_file.o: common.o
sim_console.o: sim_console.o:
@ -64,6 +66,9 @@ loadstore_tb: loadstore_tb.o
multiply_tb: multiply_tb.o multiply_tb: multiply_tb.o
$(GHDL) -e $(GHDLFLAGS) $@ $(GHDL) -e $(GHDLFLAGS) $@


divider_tb: divider_tb.o
$(GHDL) -e $(GHDLFLAGS) $@

simple_ram_tb: simple_ram_tb.o simple_ram_tb: simple_ram_tb.o
$(GHDL) -e $(GHDLFLAGS) $@ $(GHDL) -e $(GHDLFLAGS) $@



@ -73,6 +73,19 @@ package common is
end record; end record;
constant Decode2ToMultiplyInit : Decode2ToMultiplyType := (valid => '0', insn_type => OP_ILLEGAL, rc => '0', others => (others => '0')); constant Decode2ToMultiplyInit : Decode2ToMultiplyType := (valid => '0', insn_type => OP_ILLEGAL, rc => '0', others => (others => '0'));


type Decode2ToDividerType is record
valid: std_ulogic;
write_reg: std_ulogic_vector(4 downto 0);
dividend: std_ulogic_vector(63 downto 0);
divisor: std_ulogic_vector(63 downto 0);
neg_result: std_ulogic;
is_32bit: std_ulogic;
is_extended: std_ulogic;
is_modulus: std_ulogic;
rc: std_ulogic;
end record;
constant Decode2ToDividerInit: Decode2ToDividerType := (valid => '0', neg_result => '0', is_32bit => '0', is_extended => '0', is_modulus => '0', rc => '0', others => (others => '0'));

type Decode2ToRegisterFileType is record type Decode2ToRegisterFileType is record
read1_enable : std_ulogic; read1_enable : std_ulogic;
read1_reg : std_ulogic_vector(4 downto 0); read1_reg : std_ulogic_vector(4 downto 0);
@ -173,6 +186,18 @@ package common is
end record; 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', write_cr_enable => '0', others => (others => '0'));


type DividerToWritebackType is record
valid: std_ulogic;

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);
end record;
constant DividerToWritebackInit : DividerToWritebackType := (valid => '0', write_reg_enable => '0', write_cr_enable => '0', others => (others => '0'));

type WritebackToRegisterFileType is record type WritebackToRegisterFileType is record
write_reg : std_ulogic_vector(4 downto 0); write_reg : std_ulogic_vector(4 downto 0);
write_data : std_ulogic_vector(63 downto 0); write_data : std_ulogic_vector(63 downto 0);

@ -63,6 +63,10 @@ architecture behave of core is
signal decode2_to_multiply: Decode2ToMultiplyType; signal decode2_to_multiply: Decode2ToMultiplyType;
signal multiply_to_writeback: MultiplyToWritebackType; signal multiply_to_writeback: MultiplyToWritebackType;


-- divider signals
signal decode2_to_divider: Decode2ToDividerType;
signal divider_to_writeback: DividerToWritebackType;

-- local signals -- local signals
signal fetch1_stall_in : std_ulogic; signal fetch1_stall_in : std_ulogic;
signal fetch2_stall_in : std_ulogic; signal fetch2_stall_in : std_ulogic;
@ -146,6 +150,7 @@ begin
e_out => decode2_to_execute1, e_out => decode2_to_execute1,
l_out => decode2_to_loadstore1, l_out => decode2_to_loadstore1,
m_out => decode2_to_multiply, m_out => decode2_to_multiply,
d_out => decode2_to_divider,
r_in => register_file_to_decode2, r_in => register_file_to_decode2,
r_out => decode2_to_register_file, r_out => decode2_to_register_file,
c_in => cr_file_to_decode2, c_in => cr_file_to_decode2,
@ -211,12 +216,21 @@ begin
m_out => multiply_to_writeback m_out => multiply_to_writeback
); );


divider_0: entity work.divider
port map (
clk => clk,
rst => rst,
d_in => decode2_to_divider,
d_out => divider_to_writeback
);

writeback_0: entity work.writeback writeback_0: entity work.writeback
port map ( port map (
clk => clk, clk => clk,
e_in => execute2_to_writeback, e_in => execute2_to_writeback,
l_in => loadstore2_to_writeback, l_in => loadstore2_to_writeback,
m_in => multiply_to_writeback, m_in => multiply_to_writeback,
d_in => divider_to_writeback,
w_out => writeback_to_register_file, w_out => writeback_to_register_file,
c_out => writeback_to_cr_file, c_out => writeback_to_cr_file,
complete_out => complete complete_out => complete

@ -79,14 +79,7 @@ architecture behaviour of decode1 is
PPC_DCBT => (ALU, OP_NOP, NONE, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), PPC_DCBT => (ALU, OP_NOP, NONE, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'),
PPC_DCBTST => (ALU, OP_NOP, NONE, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), PPC_DCBTST => (ALU, OP_NOP, NONE, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'),
--PPC_DCBZ --PPC_DCBZ
PPC_DIVD => (ALU, OP_DIVD, RA, RB, NONE, RT, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'), PPC_DIV => (DIV, OP_DIV, RA, RB, NONE, RT, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
--PPC_DIVDE
--PPC_DIVDEU
PPC_DIVDU => (ALU, OP_DIVDU, RA, RB, NONE, RT, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
PPC_DIVW => (ALU, OP_DIVW, RA, RB, NONE, RT, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
--PPC_DIVWE
--PPC_DIVWEU
PPC_DIVWU => (ALU, OP_DIVWU, RA, RB, NONE, RT, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
PPC_EQV => (ALU, OP_EQV, RS, RB, NONE, RA, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'), PPC_EQV => (ALU, OP_EQV, RS, RB, NONE, RA, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
PPC_EXTSB => (ALU, OP_EXTSB, RS, NONE, NONE, RA, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'), PPC_EXTSB => (ALU, OP_EXTSB, RS, NONE, NONE, RA, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
PPC_EXTSH => (ALU, OP_EXTSH, RS, NONE, NONE, RA, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'), PPC_EXTSH => (ALU, OP_EXTSH, RS, NONE, NONE, RA, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
@ -141,10 +134,7 @@ architecture behaviour of decode1 is
PPC_MTCTR => (ALU, OP_MTCTR, RS, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), PPC_MTCTR => (ALU, OP_MTCTR, RS, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'),
PPC_MTLR => (ALU, OP_MTLR, RS, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), PPC_MTLR => (ALU, OP_MTLR, RS, NONE, NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'),
--PPC_MFSPR --PPC_MFSPR
--PPC_MODSD PPC_MOD => (DIV, OP_MOD, RA, RB, NONE, RT, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC, '0', '1'),
--PPC_MODSW
--PPC_MODUD
--PPC_MODUW
PPC_MTCRF => (ALU, OP_MTCRF, RS, NONE, NONE, NONE, FXM, NONE, NONE, '0', '1', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), PPC_MTCRF => (ALU, OP_MTCRF, RS, NONE, NONE, NONE, FXM, NONE, NONE, '0', '1', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'),
PPC_MTOCRF => (ALU, OP_MTOCRF, RS, NONE, NONE, NONE, FXM, NONE, NONE, '0', '1', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), PPC_MTOCRF => (ALU, OP_MTOCRF, RS, NONE, NONE, NONE, FXM, NONE, NONE, '0', '1', '0', '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'),
--PPC_MTSPR --PPC_MTSPR
@ -404,30 +394,9 @@ begin
elsif std_match(f_in.insn, "011111---------------1111110110-") then elsif std_match(f_in.insn, "011111---------------1111110110-") then
report "PPC_dcbz"; report "PPC_dcbz";
ppc_insn := PPC_DCBZ; ppc_insn := PPC_DCBZ;
elsif std_match(f_in.insn, "011111---------------0111101001-") then elsif std_match(f_in.insn, "011111----------------11--010-1-") then
report "PPC_divd"; report "PPC_div";
ppc_insn := PPC_DIVD; ppc_insn := PPC_DIV;
elsif std_match(f_in.insn, "011111---------------0110101001-") then
report "PPC_divde";
ppc_insn := PPC_DIVDE;
elsif std_match(f_in.insn, "011111---------------0110001001-") then
report "PPC_divdeu";
ppc_insn := PPC_DIVDEU;
elsif std_match(f_in.insn, "011111---------------0111001001-") then
report "PPC_divdu";
ppc_insn := PPC_DIVDU;
elsif std_match(f_in.insn, "011111---------------0111101011-") then
report "PPC_divw";
ppc_insn := PPC_DIVW;
elsif std_match(f_in.insn, "011111---------------0110101011-") then
report "PPC_divwe";
ppc_insn := PPC_DIVWE;
elsif std_match(f_in.insn, "011111---------------0110001011-") then
report "PPC_divweu";
ppc_insn := PPC_DIVWEU;
elsif std_match(f_in.insn, "011111---------------0111001011-") then
report "PPC_divwu";
ppc_insn := PPC_DIVWU;
elsif std_match(f_in.insn, "011111---------------0100011100-") then elsif std_match(f_in.insn, "011111---------------0100011100-") then
report "PPC_eqv"; report "PPC_eqv";
ppc_insn := PPC_EQV; ppc_insn := PPC_EQV;
@ -588,18 +557,9 @@ begin
elsif std_match(f_in.insn, "011111---------------0101010011-") then elsif std_match(f_in.insn, "011111---------------0101010011-") then
report "PPC_mfspr"; report "PPC_mfspr";
ppc_insn := PPC_MFSPR; ppc_insn := PPC_MFSPR;
elsif std_match(f_in.insn, "011111---------------1100001001-") then elsif std_match(f_in.insn, "011111----------------1000010-1-") then
report "PPC_modsd"; report "PPC_mod";
ppc_insn := PPC_MODSD; ppc_insn := PPC_MOD;
elsif std_match(f_in.insn, "011111---------------1100001011-") then
report "PPC_modsw";
ppc_insn := PPC_MODSW;
elsif std_match(f_in.insn, "011111---------------0100001001-") then
report "PPC_modud";
ppc_insn := PPC_MODUD;
elsif std_match(f_in.insn, "011111---------------0100001011-") then
report "PPC_moduw";
ppc_insn := PPC_MODUW;
elsif std_match(f_in.insn, "011111-----0---------0010010000-") then elsif std_match(f_in.insn, "011111-----0---------0010010000-") then
report "PPC_mtcrf"; report "PPC_mtcrf";
ppc_insn := PPC_MTCRF; ppc_insn := PPC_MTCRF;

@ -22,6 +22,7 @@ entity decode2 is


e_out : out Decode2ToExecute1Type; e_out : out Decode2ToExecute1Type;
m_out : out Decode2ToMultiplyType; m_out : out Decode2ToMultiplyType;
d_out : out Decode2ToDividerType;
l_out : out Decode2ToLoadstore1Type; l_out : out Decode2ToLoadstore1Type;


r_in : in RegisterFileToDecode2Type; r_in : in RegisterFileToDecode2Type;
@ -43,6 +44,7 @@ architecture behaviour of decode2 is
type reg_type is record type reg_type is record
e : Decode2ToExecute1Type; e : Decode2ToExecute1Type;
m : Decode2ToMultiplyType; m : Decode2ToMultiplyType;
d : Decode2ToDividerType;
l : Decode2ToLoadstore1Type; l : Decode2ToLoadstore1Type;
end record; end record;


@ -190,7 +192,7 @@ begin
if rising_edge(clk) then if rising_edge(clk) then
assert r_int.outstanding <= 1 report "Outstanding bad " & integer'image(r_int.outstanding) severity failure; assert r_int.outstanding <= 1 report "Outstanding bad " & integer'image(r_int.outstanding) severity failure;


if rin.e.valid = '1' or rin.l.valid = '1' or rin.m.valid = '1' then if rin.e.valid = '1' or rin.l.valid = '1' or rin.m.valid = '1' or rin.d.valid = '1' then
report "execute " & to_hstring(rin.e.nia); report "execute " & to_hstring(rin.e.nia);
end if; end if;
r <= rin; r <= rin;
@ -217,9 +219,13 @@ begin
variable v_int : reg_internal_type; variable v_int : reg_internal_type;
variable mul_a : std_ulogic_vector(63 downto 0); variable mul_a : std_ulogic_vector(63 downto 0);
variable mul_b : std_ulogic_vector(63 downto 0); variable mul_b : std_ulogic_vector(63 downto 0);
variable dividend : std_ulogic_vector(63 downto 0);
variable divisor : std_ulogic_vector(63 downto 0);
variable absdend : std_ulogic_vector(31 downto 0);
variable decoded_reg_a : decode_input_reg_t; variable decoded_reg_a : decode_input_reg_t;
variable decoded_reg_b : decode_input_reg_t; variable decoded_reg_b : decode_input_reg_t;
variable decoded_reg_c : decode_input_reg_t; variable decoded_reg_c : decode_input_reg_t;
variable signed_division: std_ulogic;
variable is_valid : std_ulogic; variable is_valid : std_ulogic;
begin begin
v := r; v := r;
@ -228,6 +234,7 @@ begin
v.e := Decode2ToExecute1Init; v.e := Decode2ToExecute1Init;
v.l := Decode2ToLoadStore1Init; v.l := Decode2ToLoadStore1Init;
v.m := Decode2ToMultiplyInit; v.m := Decode2ToMultiplyInit;
v.d := Decode2ToDividerInit;


mul_a := (others => '0'); mul_a := (others => '0');
mul_b := (others => '0'); mul_b := (others => '0');
@ -290,6 +297,73 @@ begin
end if; end if;
end if; end if;


-- divide unit
-- PPC divide and modulus instruction words have these bits in
-- the bottom 11 bits: o1dns 010t1 r
-- where o = OE for div instrs, signedness for mod instrs
-- d = 1 for div*, 0 for mod*
-- n = 1 for normal, 0 for extended (dividend << 32/64)
-- s = 1 for signed, 0 for unsigned (for div*)
-- t = 1 for 32-bit, 0 for 64-bit
-- r = RC bit (record condition code)
-- For signed division/modulus, we take absolute values and
-- tell the divider what the sign of the result should be,
-- which is the dividend sign for modulus, and the XOR of
-- the dividend and divisor signs for division.
dividend := decoded_reg_a.data;
divisor := decoded_reg_b.data;
v.d.write_reg := decode_output_reg(d_in.decode.output_reg_a, d_in.insn);
v.d.is_modulus := not d_in.insn(8);
if d_in.insn(8) = '1' then
signed_division := d_in.insn(6);
else
signed_division := d_in.insn(10);
end if;
if d_in.insn(2) = '0' then
-- 64-bit forms
v.d.is_32bit := '0';
if d_in.insn(8) = '1' and d_in.insn(7) = '0' then
v.d.is_extended := '1';
end if;
if signed_division = '1' and dividend(63) = '1' then
v.d.neg_result := '1';
v.d.dividend := std_ulogic_vector(- signed(dividend));
else
v.d.dividend := dividend;
end if;
if signed_division = '1' and divisor(63) = '1' then
if d_in.insn(8) = '1' then
v.d.neg_result := not v.d.neg_result;
end if;
v.d.divisor := std_ulogic_vector(- signed(divisor));
else
v.d.divisor := divisor;
end if;
else
-- 32-bit forms
v.d.is_32bit := '1';
if signed_division = '1' and dividend(31) = '1' then
v.d.neg_result := '1';
absdend := std_ulogic_vector(- signed(dividend(31 downto 0)));
else
absdend := dividend(31 downto 0);
end if;
if d_in.insn(8) = '1' and d_in.insn(7) = '0' then -- extended forms
v.d.dividend := absdend & x"00000000";
else
v.d.dividend := x"00000000" & absdend;
end if;
if signed_division = '1' and divisor(31) = '1' then
if d_in.insn(8) = '1' then
v.d.neg_result := not v.d.neg_result;
end if;
v.d.divisor := x"00000000" & std_ulogic_vector(- signed(divisor(31 downto 0)));
else
v.d.divisor := x"00000000" & divisor(31 downto 0);
end if;
end if;
v.d.rc := decode_rc(d_in.decode.rc, d_in.insn);

-- load/store unit -- load/store unit
v.l.update_reg := decoded_reg_a.reg; v.l.update_reg := decoded_reg_a.reg;
v.l.addr1 := decoded_reg_a.data; v.l.addr1 := decoded_reg_a.data;
@ -363,6 +437,7 @@ begin


v.e.valid := '0'; v.e.valid := '0';
v.m.valid := '0'; v.m.valid := '0';
v.d.valid := '0';
v.l.valid := '0'; v.l.valid := '0';
case d_in.decode.unit is case d_in.decode.unit is
when ALU => when ALU =>
@ -371,6 +446,8 @@ begin
v.l.valid := is_valid; v.l.valid := is_valid;
when MUL => when MUL =>
v.m.valid := is_valid; v.m.valid := is_valid;
when DIV =>
v.d.valid := is_valid;
when NONE => when NONE =>
v.e.valid := is_valid; v.e.valid := is_valid;
v.e.insn_type := OP_ILLEGAL; v.e.insn_type := OP_ILLEGAL;
@ -379,11 +456,12 @@ begin
if flush_in = '1' then if flush_in = '1' then
v.e.valid := '0'; v.e.valid := '0';
v.m.valid := '0'; v.m.valid := '0';
v.d.valid := '0';
v.l.valid := '0'; v.l.valid := '0';
end if; end if;


-- track outstanding instructions -- track outstanding instructions
if v.e.valid = '1' or v.l.valid = '1' or v.m.valid = '1' then if v.e.valid = '1' or v.l.valid = '1' or v.m.valid = '1' or v.d.valid = '1' then
v_int.outstanding := v_int.outstanding + 1; v_int.outstanding := v_int.outstanding + 1;
end if; end if;


@ -393,6 +471,7 @@ begin
v.e := Decode2ToExecute1Init; v.e := Decode2ToExecute1Init;
v.l := Decode2ToLoadStore1Init; v.l := Decode2ToLoadStore1Init;
v.m := Decode2ToMultiplyInit; v.m := Decode2ToMultiplyInit;
v.d := Decode2ToDividerInit;
end if; end if;


-- Update registers -- Update registers
@ -403,5 +482,6 @@ begin
e_out <= r.e; e_out <= r.e;
l_out <= r.l; l_out <= r.l;
m_out <= r.m; m_out <= r.m;
d_out <= r.d;
end process; end process;
end architecture behaviour; end architecture behaviour;

@ -11,9 +11,8 @@ package decode_types is
PPC_CMPRB, PPC_CNTLZD, PPC_CNTLZW, PPC_CNTTZD, PPC_CNTTZW, PPC_CMPRB, PPC_CNTLZD, PPC_CNTLZW, PPC_CNTTZD, PPC_CNTTZW,
PPC_CRAND, PPC_CRANDC, PPC_CREQV, PPC_CRNAND, PPC_CRNOR, PPC_CRAND, PPC_CRANDC, PPC_CREQV, PPC_CRNAND, PPC_CRNOR,
PPC_CROR, PPC_CRORC, PPC_CRXOR, PPC_DARN, PPC_DCBF, PPC_DCBST, PPC_CROR, PPC_CRORC, PPC_CRXOR, PPC_DARN, PPC_DCBF, PPC_DCBST,
PPC_DCBT, PPC_DCBTST, PPC_DCBZ, PPC_DIVD, PPC_DIVDE, PPC_DCBT, PPC_DCBTST, PPC_DCBZ, PPC_DIV,
PPC_DIVDEU, PPC_DIVDU, PPC_DIVW, PPC_DIVWE, PPC_DIVWEU, PPC_EQV, PPC_EXTSB, PPC_EXTSH, PPC_EXTSW,
PPC_DIVWU, PPC_EQV, PPC_EXTSB, PPC_EXTSH, PPC_EXTSW,
PPC_EXTSWSLI, PPC_ICBI, PPC_ICBT, PPC_ISEL, PPC_ISYNC, PPC_EXTSWSLI, PPC_ICBI, PPC_ICBT, PPC_ISEL, PPC_ISYNC,
PPC_LBARX, PPC_LBZ, PPC_LBZU, PPC_LBZUX, PPC_LBZX, PPC_LD, PPC_LBARX, PPC_LBZ, PPC_LBZU, PPC_LBZUX, PPC_LBZX, PPC_LD,
PPC_LDARX, PPC_LDBRX, PPC_LDU, PPC_LDUX, PPC_LDX, PPC_LHA, PPC_LDARX, PPC_LDBRX, PPC_LDU, PPC_LDUX, PPC_LDX, PPC_LHA,
@ -22,7 +21,7 @@ package decode_types is
PPC_LWAX, PPC_LWBRX, PPC_LWZ, PPC_LWZU, PPC_LWZUX, PPC_LWZX, PPC_LWAX, PPC_LWBRX, PPC_LWZ, PPC_LWZU, PPC_LWZUX, PPC_LWZX,
PPC_MADDHD, PPC_MADDHDU, PPC_MADDLD, PPC_MCRF, PPC_MCRXR, PPC_MADDHD, PPC_MADDHDU, PPC_MADDLD, PPC_MCRF, PPC_MCRXR,
PPC_MCRXRX, PPC_MFCR, PPC_MFOCRF, PPC_MFSPR, PPC_MFTB, PPC_MCRXRX, PPC_MFCR, PPC_MFOCRF, PPC_MFSPR, PPC_MFTB,
PPC_MODSD, PPC_MODSW, PPC_MODUD, PPC_MODUW, PPC_MTCRF, PPC_MOD, PPC_MTCRF,
PPC_MFCTR, PPC_MTCTR, PPC_MFLR, PPC_MTLR, PPC_MTOCRF, PPC_MFCTR, PPC_MTCTR, PPC_MFLR, PPC_MTLR, PPC_MTOCRF,
PPC_MTSPR, PPC_MULHD, PPC_MULHDU, PPC_MULHW, PPC_MULHWU, PPC_MTSPR, PPC_MULHD, PPC_MULHDU, PPC_MULHW, PPC_MULHWU,
PPC_MULLD, PPC_MULLI, PPC_MULLW, PPC_NAND, PPC_NEG, PPC_NOR, PPC_NOP, PPC_MULLD, PPC_MULLI, PPC_MULLW, PPC_NAND, PPC_NEG, PPC_NOR, PPC_NOP,
@ -46,12 +45,11 @@ package decode_types is
OP_CNTLZD, OP_CNTLZW, OP_CNTTZD, OP_CNTTZW, OP_CRAND, OP_CNTLZD, OP_CNTLZW, OP_CNTTZD, OP_CNTTZW, OP_CRAND,
OP_CRANDC, OP_CREQV, OP_CRNAND, OP_CRNOR, OP_CROR, OP_CRORC, 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_CRXOR, OP_DARN, OP_DCBF, OP_DCBST, OP_DCBT, OP_DCBTST,
OP_DCBZ, OP_DIVD, OP_DIVDE, OP_DIVDEU, OP_DIVDU, OP_DIVW, OP_DCBZ, OP_DIV, OP_EQV, OP_EXTSB, OP_EXTSH,
OP_DIVWE, OP_DIVWEU, OP_DIVWU, OP_EQV, OP_EXTSB, OP_EXTSH,
OP_EXTSW, OP_EXTSWSLI, OP_ICBI, OP_ICBT, OP_ISEL, OP_ISYNC, OP_EXTSW, OP_EXTSWSLI, OP_ICBI, OP_ICBT, OP_ISEL, OP_ISYNC,
OP_LOAD, OP_STORE, OP_MADDHD, OP_MADDHDU, OP_MADDLD, OP_MCRF, OP_LOAD, OP_STORE, OP_MADDHD, OP_MADDHDU, OP_MADDLD, OP_MCRF,
OP_MCRXR, OP_MCRXRX, OP_MFCR, OP_MFOCRF, OP_MFCTR, OP_MFLR, OP_MCRXR, OP_MCRXRX, OP_MFCR, OP_MFOCRF, OP_MFCTR, OP_MFLR,
OP_MFTB, OP_MFSPR, OP_MODSD, OP_MODSW, OP_MODUD, OP_MODUW, OP_MFTB, OP_MFSPR, OP_MOD,
OP_MTCRF, OP_MTOCRF, OP_MTCTR, OP_MTLR, OP_MTSPR, OP_MUL_L64, OP_MTCRF, OP_MTOCRF, OP_MTCTR, OP_MTLR, OP_MTSPR, OP_MUL_L64,
OP_MUL_H64, OP_MUL_H32, OP_NAND, OP_NEG, OP_NOR, OP_OR, OP_MUL_H64, OP_MUL_H32, OP_NAND, OP_NEG, OP_NOR, OP_OR,
OP_ORC, OP_POPCNTB, OP_POPCNTD, OP_POPCNTW, OP_PRTYD, OP_ORC, OP_POPCNTB, OP_POPCNTD, OP_POPCNTW, OP_PRTYD,
@ -88,7 +86,7 @@ package decode_types is


constant TOO_OFFSET : integer := 0; constant TOO_OFFSET : integer := 0;


type unit_t is (NONE, ALU, LDST, MUL); type unit_t is (NONE, ALU, LDST, MUL, DIV);
type length_t is (NONE, is1B, is2B, is4B, is8B); type length_t is (NONE, is1B, is2B, is4B, is8B);


type decode_rom_t is record type decode_rom_t is record

@ -0,0 +1,127 @@
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

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

entity divider is
port (
clk : in std_logic;
rst : in std_logic;
d_in : in Decode2ToDividerType;
d_out : out DividerToWritebackType
);
end entity divider;

architecture behaviour of divider is
signal dend : std_ulogic_vector(127 downto 0);
signal div : unsigned(63 downto 0);
signal quot : std_ulogic_vector(63 downto 0);
signal result : std_ulogic_vector(63 downto 0);
signal sresult : std_ulogic_vector(63 downto 0);
signal qbit : std_ulogic;
signal running : std_ulogic;
signal count : unsigned(6 downto 0);
signal neg_result : std_ulogic;
signal is_modulus : std_ulogic;
signal is_32bit : std_ulogic;
signal rc : std_ulogic;
signal write_reg : std_ulogic_vector(4 downto 0);

function compare_zero(value : std_ulogic_vector(63 downto 0); is_32 : std_ulogic)
return std_ulogic_vector is
begin
if is_32 = '1' then
if value(31) = '1' then
return "1000";
elsif unsigned(value(30 downto 0)) > 0 then
return "0100";
else
return "0010";
end if;
else
if value(63) = '1' then
return "1000";
elsif unsigned(value(62 downto 0)) > 0 then
return "0100";
else
return "0010";
end if;
end if;
end function compare_zero;

begin
divider_0: process(clk)
begin
if rising_edge(clk) then
if rst = '1' then
dend <= (others => '0');
div <= (others => '0');
quot <= (others => '0');
running <= '0';
count <= "0000000";
elsif d_in.valid = '1' then
if d_in.is_extended = '1' then
dend <= d_in.dividend & x"0000000000000000";
else
dend <= x"0000000000000000" & d_in.dividend;
end if;
div <= unsigned(d_in.divisor);
quot <= (others => '0');
write_reg <= d_in.write_reg;
neg_result <= d_in.neg_result;
is_modulus <= d_in.is_modulus;
is_32bit <= d_in.is_32bit;
rc <= d_in.rc;
count <= "0000000";
running <= '1';
elsif running = '1' then
if dend(127) = '1' or unsigned(dend(126 downto 63)) >= div then
dend <= std_ulogic_vector(unsigned(dend(126 downto 63)) - div) &
dend(62 downto 0) & '0';
quot <= quot(62 downto 0) & '1';
else
dend <= dend(126 downto 0) & '0';
quot <= quot(62 downto 0) & '0';
end if;
if count = "0111111" then
running <= '0';
end if;
count <= count + 1;
else
count <= "0000000";
end if;
end if;
end process;

divider_1: process(all)
begin
d_out <= DividerToWritebackInit;
d_out.write_reg_nr <= write_reg;

if count(6) = '1' then
d_out.valid <= '1';
d_out.write_reg_enable <= '1';
if is_modulus = '1' then
result <= dend(127 downto 64);
else
result <= quot;
end if;
if neg_result = '1' then
sresult <= std_ulogic_vector(- signed(result));
else
sresult <= result;
end if;
d_out.write_reg_data <= sresult;
if rc = '1' then
d_out.write_cr_enable <= '1';
d_out.write_cr_mask <= num_to_fxm(0);
d_out.write_cr_data <= compare_zero(sresult, is_32bit) & x"0000000";
end if;
end if;
end process;

end architecture behaviour;

@ -0,0 +1,613 @@
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.glibc_random.all;
use work.ppc_fx_insns.all;

entity divider_tb is
end divider_tb;

architecture behave of divider_tb is
signal clk : std_ulogic;
signal rst : std_ulogic;
constant clk_period : time := 10 ns;

signal d1 : Decode2ToDividerType;
signal d2 : DividerToWritebackType;
begin
divider_0: entity work.divider
port map (clk => clk, rst => rst, d_in => d1, d_out => d2);

clk_process: process
begin
clk <= '0';
wait for clk_period/2;
clk <= '1';
wait for clk_period/2;
end process;

stim_process: process
variable ra, rb, rt, behave_rt: std_ulogic_vector(63 downto 0);
variable si: std_ulogic_vector(15 downto 0);
variable d128: std_ulogic_vector(127 downto 0);
variable q128: std_ulogic_vector(127 downto 0);
begin
rst <= '1';
wait for clk_period;
rst <= '0';

d1.valid <= '1';
d1.write_reg <= "10001";
d1.dividend <= x"0000000010001000";
d1.divisor <= x"0000000000001111";
d1.neg_result <= '0';
d1.is_32bit <= '0';
d1.is_extended <= '0';
d1.is_modulus <= '0';
d1.rc <= '0';

wait for clk_period;
assert d2.valid = '0';

d1.valid <= '0';

for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;

assert d2.valid = '1';
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';

wait for clk_period;
assert d2.valid = '0' report "valid";

d1.valid <= '1';
d1.rc <= '1';

wait for clk_period;
assert d2.valid = '0' report "valid";

d1.valid <= '0';

for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;

assert d2.valid = '1';
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);

wait for clk_period;
assert d2.valid = '0';

-- test divd
report "test divd";
divd_loop : for dlength in 1 to 8 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(signed(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(signed(pseudorand(vlength * 8)), 64));

if ra(63) = '1' then
d1.dividend <= std_ulogic_vector(- signed(ra));
else
d1.dividend <= ra;
end if;
if rb(63) = '1' then
d1.divisor <= std_ulogic_vector(- signed(rb));
else
d1.divisor <= rb;
end if;
if ra(63) = rb(63) then
d1.neg_result <= '0';
else
d1.neg_result <= '1';
end if;
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := ppc_divd(ra, rb);
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 if;
end loop;
end loop;
end loop;

-- test divdu
report "test divdu";
divdu_loop : for dlength in 1 to 8 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(unsigned(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(unsigned(pseudorand(vlength * 8)), 64));

d1.dividend <= ra;
d1.divisor <= rb;
d1.neg_result <= '0';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := ppc_divdu(ra, rb);
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 if;
end loop;
end loop;
end loop;

-- test divde
report "test divde";
divde_loop : for vlength in 1 to 8 loop
for dlength in 1 to vlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(signed(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(signed(pseudorand(vlength * 8)), 64));

if ra(63) = '1' then
d1.dividend <= std_ulogic_vector(- signed(ra));
else
d1.dividend <= ra;
end if;
if rb(63) = '1' then
d1.divisor <= std_ulogic_vector(- signed(rb));
else
d1.divisor <= rb;
end if;
if ra(63) = rb(63) then
d1.neg_result <= '0';
else
d1.neg_result <= '1';
end if;
d1.is_extended <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if unsigned(d1.divisor) > unsigned(d1.dividend) then
d128 := ra & x"0000000000000000";
q128 := std_ulogic_vector(signed(d128) / signed(rb));
behave_rt := q128(63 downto 0);
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 if;
end loop;
end loop;
end loop;

-- test divdeu
report "test divdeu";
divdeu_loop : for vlength in 1 to 8 loop
for dlength in 1 to vlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(unsigned(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(unsigned(pseudorand(vlength * 8)), 64));

d1.dividend <= ra;
d1.divisor <= rb;
d1.neg_result <= '0';
d1.is_extended <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if unsigned(d1.divisor) > unsigned(d1.dividend) then
d128 := ra & x"0000000000000000";
q128 := std_ulogic_vector(unsigned(d128) / unsigned(rb));
behave_rt := q128(63 downto 0);
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 if;
end loop;
end loop;
end loop;

-- test divw
report "test divw";
divw_loop : for dlength in 1 to 4 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(signed(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(signed(pseudorand(vlength * 8)), 64));

if ra(63) = '1' then
d1.dividend <= std_ulogic_vector(- signed(ra));
else
d1.dividend <= ra;
end if;
if rb(63) = '1' then
d1.divisor <= std_ulogic_vector(- signed(rb));
else
d1.divisor <= rb;
end if;
if ra(63) = rb(63) then
d1.neg_result <= '0';
else
d1.neg_result <= '1';
end if;
d1.is_extended <= '0';
d1.is_32bit <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := ppc_divw(ra, rb);
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
report "bad divw expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divw";
end if;
end loop;
end loop;
end loop;

-- test divwu
report "test divwu";
divwu_loop : for dlength in 1 to 4 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(unsigned(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(unsigned(pseudorand(vlength * 8)), 64));

d1.dividend <= ra;
d1.divisor <= rb;
d1.neg_result <= '0';
d1.is_extended <= '0';
d1.is_32bit <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := ppc_divwu(ra, rb);
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
report "bad divwu expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divwu";
end if;
end loop;
end loop;
end loop;

-- test divwe
report "test divwe";
divwe_loop : for vlength in 1 to 4 loop
for dlength in 1 to vlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(signed(pseudorand(dlength * 8)), 32)) & x"00000000";
rb := std_ulogic_vector(resize(signed(pseudorand(vlength * 8)), 64));

if ra(63) = '1' then
d1.dividend <= std_ulogic_vector(- signed(ra));
else
d1.dividend <= ra;
end if;
if rb(63) = '1' then
d1.divisor <= std_ulogic_vector(- signed(rb));
else
d1.divisor <= rb;
end if;
if ra(63) = rb(63) then
d1.neg_result <= '0';
else
d1.neg_result <= '1';
end if;
d1.is_extended <= '0';
d1.is_32bit <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if unsigned(d1.divisor(31 downto 0)) > unsigned(d1.dividend(63 downto 32)) then
behave_rt := std_ulogic_vector(signed(ra) / signed(rb));
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divwe";
end if;
end loop;
end loop;
end loop;

-- test divweu
report "test divweu";
divweu_loop : for vlength in 1 to 4 loop
for dlength in 1 to vlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(unsigned(pseudorand(dlength * 8)), 32)) & x"00000000";
rb := std_ulogic_vector(resize(unsigned(pseudorand(vlength * 8)), 64));

d1.dividend <= ra;
d1.divisor <= rb;
d1.neg_result <= '0';
d1.is_extended <= '0';
d1.is_32bit <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if unsigned(d1.divisor(31 downto 0)) > unsigned(d1.dividend(63 downto 32)) then
behave_rt := std_ulogic_vector(unsigned(ra) / unsigned(rb));
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divweu";
end if;
end loop;
end loop;
end loop;

-- test modsd
report "test modsd";
modsd_loop : for dlength in 1 to 8 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(signed(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(signed(pseudorand(vlength * 8)), 64));

if ra(63) = '1' then
d1.dividend <= std_ulogic_vector(- signed(ra));
else
d1.dividend <= ra;
end if;
if rb(63) = '1' then
d1.divisor <= std_ulogic_vector(- signed(rb));
else
d1.divisor <= rb;
end if;
d1.neg_result <= ra(63);
d1.is_extended <= '0';
d1.is_32bit <= '0';
d1.is_modulus <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := std_ulogic_vector(signed(ra) rem signed(rb));
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 if;
end loop;
end loop;
end loop;

-- test modud
report "test modud";
modud_loop : for dlength in 1 to 8 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(unsigned(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(unsigned(pseudorand(vlength * 8)), 64));

d1.dividend <= ra;
d1.divisor <= rb;
d1.neg_result <= '0';
d1.is_extended <= '0';
d1.is_32bit <= '0';
d1.is_modulus <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := std_ulogic_vector(unsigned(ra) rem unsigned(rb));
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 if;
end loop;
end loop;
end loop;

-- test modsw
report "test modsw";
modsw_loop : for dlength in 1 to 4 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(signed(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(signed(pseudorand(vlength * 8)), 64));

if ra(63) = '1' then
d1.dividend <= std_ulogic_vector(- signed(ra));
else
d1.dividend <= ra;
end if;
if rb(63) = '1' then
d1.divisor <= std_ulogic_vector(- signed(rb));
else
d1.divisor <= rb;
end if;
d1.neg_result <= ra(63);
d1.is_extended <= '0';
d1.is_32bit <= '1';
d1.is_modulus <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := x"00000000" & std_ulogic_vector(signed(ra(31 downto 0)) rem signed(rb(31 downto 0)));
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
report "bad modsw expected " & to_hstring(behave_rt) & " got " & to_hstring(d2.write_reg_data);
assert ppc_cmpi('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for modsw";
end if;
end loop;
end loop;
end loop;

-- test moduw
report "test moduw";
moduw_loop : for dlength in 1 to 4 loop
for vlength in 1 to dlength loop
for i in 0 to 100 loop
ra := std_ulogic_vector(resize(unsigned(pseudorand(dlength * 8)), 64));
rb := std_ulogic_vector(resize(unsigned(pseudorand(vlength * 8)), 64));

d1.dividend <= ra;
d1.divisor <= rb;
d1.neg_result <= '0';
d1.is_extended <= '0';
d1.is_32bit <= '1';
d1.is_modulus <= '1';
d1.valid <= '1';

wait for clk_period;

d1.valid <= '0';
for j in 0 to 64 loop
wait for clk_period;
if d2.valid = '1' then
exit;
end if;
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := x"00000000" & std_ulogic_vector(unsigned(ra(31 downto 0)) rem unsigned(rb(31 downto 0)));
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for moduw";
end if;
end loop;
end loop;
end loop;

assert false report "end of test" severity failure;
wait;
end process;
end behave;

@ -332,38 +332,6 @@ begin
-- Keep our test cases happy for now, ignore trap instructions -- Keep our test cases happy for now, ignore trap instructions
report "OP_TDI FIXME"; report "OP_TDI FIXME";


when OP_DIVDU =>
if SIM = true then
result := ppc_divdu(e_in.read_data1, e_in.read_data2);
result_en := 1;
else
terminate_out <= '1';
report "illegal";
end if;
when OP_DIVD =>
if SIM = true then
result := ppc_divd(e_in.read_data1, e_in.read_data2);
result_en := 1;
else
terminate_out <= '1';
report "illegal";
end if;
when OP_DIVWU =>
if SIM = true then
result := ppc_divwu(e_in.read_data1, e_in.read_data2);
result_en := 1;
else
terminate_out <= '1';
report "illegal";
end if;
when OP_DIVW =>
if SIM = true then
result := ppc_divw(e_in.read_data1, e_in.read_data2);
result_en := 1;
else
terminate_out <= '1';
report "illegal";
end if;
when others => when others =>
terminate_out <= '1'; terminate_out <= '1';
report "illegal"; report "illegal";

@ -23,6 +23,7 @@ filesets:
- loadstore1.vhdl - loadstore1.vhdl
- loadstore2.vhdl - loadstore2.vhdl
- multiply.vhdl - multiply.vhdl
- divider.vhdl
- writeback.vhdl - writeback.vhdl
- insn_helpers.vhdl - insn_helpers.vhdl
- core.vhdl - core.vhdl

@ -12,6 +12,7 @@ entity writeback is
e_in : in Execute2ToWritebackType; e_in : in Execute2ToWritebackType;
l_in : in Loadstore2ToWritebackType; l_in : in Loadstore2ToWritebackType;
m_in : in MultiplyToWritebackType; m_in : in MultiplyToWritebackType;
d_in : in DividerToWritebackType;


w_out : out WritebackToRegisterFileType; w_out : out WritebackToRegisterFileType;
c_out : out WritebackToCrFileType; c_out : out WritebackToCrFileType;
@ -26,24 +27,30 @@ begin
variable x : std_ulogic_vector(0 downto 0); variable x : std_ulogic_vector(0 downto 0);
variable y : std_ulogic_vector(0 downto 0); variable y : std_ulogic_vector(0 downto 0);
variable z : std_ulogic_vector(0 downto 0); variable z : std_ulogic_vector(0 downto 0);
variable w : std_ulogic_vector(0 downto 0);
begin begin
x := "" & e_in.valid; x := "" & e_in.valid;
y := "" & l_in.valid; y := "" & l_in.valid;
z := "" & m_in.valid; z := "" & m_in.valid;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1 severity failure; w := "" & d_in.valid;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z)) + to_integer(unsigned(w))) <= 1 severity failure;


x := "" & e_in.write_enable; x := "" & e_in.write_enable;
y := "" & l_in.write_enable; y := "" & l_in.write_enable;
z := "" & m_in.write_reg_enable; z := "" & m_in.write_reg_enable;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1 severity failure; 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;


assert not(e_in.write_cr_enable = '1' and m_in.write_cr_enable = '1'); 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_out <= WritebackToRegisterFileInit; w_out <= WritebackToRegisterFileInit;
c_out <= WritebackToCrFileInit; c_out <= WritebackToCrFileInit;


complete_out <= '0'; complete_out <= '0';
if e_in.valid = '1' or l_in.valid = '1' or m_in.valid = '1' then if e_in.valid = '1' or l_in.valid = '1' or m_in.valid = '1' or d_in.valid = '1' then
complete_out <= '1'; complete_out <= '1';
end if; end if;


@ -76,5 +83,17 @@ begin
c_out.write_cr_mask <= m_in.write_cr_mask; c_out.write_cr_mask <= m_in.write_cr_mask;
c_out.write_cr_data <= m_in.write_cr_data; c_out.write_cr_data <= m_in.write_cr_data;
end if; 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;
end if;

if d_in.write_cr_enable = '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;
end if;
end process; end process;
end; end;

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