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Merge pull request #92 from paulusmack/divider

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Divider
pull/94/head
Anton Blanchard 5 years ago committed by GitHub
parent 625eb0175f d4f51e08c8
commit bd73c1753b
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 137 additions and 108 deletions
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2
core.vhdl
Unescape Escape View File

@ -241,7 +241,7 @@ begin
divider_0: entity work.divider
port map (
clk => clk,
rst => rst,
rst => core_rst,
d_in => decode2_to_divider,
d_out => divider_to_writeback
);

2
decode2.vhdl
Unescape Escape View File

@ -249,7 +249,7 @@ begin
-- r = RC bit (record condition code)
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);
v.d.is_32bit := not d_in.insn(2);
v.d.is_32bit := d_in.insn(2);
if d_in.insn(8) = '1' then
signed_division := d_in.insn(6);
else

83
divider.vhdl
Unescape Escape View File

@ -17,7 +17,7 @@ entity divider is
end entity divider;

architecture behaviour of divider is
signal dend : std_ulogic_vector(127 downto 0);
signal dend : std_ulogic_vector(128 downto 0);
signal div : unsigned(63 downto 0);
signal quot : std_ulogic_vector(63 downto 0);
signal result : std_ulogic_vector(63 downto 0);
@ -30,30 +30,11 @@ architecture behaviour of divider is
signal is_modulus : std_ulogic;
signal is_32bit : std_ulogic;
signal extended : std_ulogic;
signal is_signed : 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;
signal overflow : std_ulogic;
signal did_ovf : std_ulogic;

begin
divider_0: process(clk)
@ -67,9 +48,9 @@ begin
count <= "0000000";
elsif d_in.valid = '1' then
if d_in.is_extended = '1' and not (d_in.is_signed = '1' and d_in.dividend(63) = '1') then
dend <= d_in.dividend & x"0000000000000000";
dend <= '0' & d_in.dividend & x"0000000000000000";
else
dend <= x"0000000000000000" & d_in.dividend;
dend <= '0' & x"0000000000000000" & d_in.dividend;
end if;
div <= unsigned(d_in.divisor);
quot <= (others => '0');
@ -78,18 +59,20 @@ begin
is_modulus <= d_in.is_modulus;
extended <= d_in.is_extended;
is_32bit <= d_in.is_32bit;
is_signed <= d_in.is_signed;
rc <= d_in.rc;
count <= "0000000";
count <= "1111111";
running <= '1';
overflow <= '0';
signcheck <= d_in.is_signed and (d_in.dividend(63) or d_in.divisor(63));
elsif signcheck = '1' then
signcheck <= '0';
neg_result <= dend(63) xor (div(63) and not is_modulus);
if dend(63) = '1' then
if extended = '1' then
dend <= std_ulogic_vector(- signed(dend(63 downto 0))) & x"0000000000000000";
dend <= '0' & std_ulogic_vector(- signed(dend(63 downto 0))) & x"0000000000000000";
else
dend <= x"0000000000000000" & std_ulogic_vector(- signed(dend(63 downto 0)));
dend <= '0' & x"0000000000000000" & std_ulogic_vector(- signed(dend(63 downto 0)));
end if;
end if;
if div(63) = '1' then
@ -99,18 +82,19 @@ begin
if count = "0111111" then
running <= '0';
end if;
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';
overflow <= quot(63);
if dend(128) = '1' or unsigned(dend(127 downto 64)) >= div then
dend <= std_ulogic_vector(unsigned(dend(127 downto 64)) - div) &
dend(63 downto 0) & '0';
quot <= quot(62 downto 0) & '1';
count <= count + 1;
elsif dend(127 downto 56) = x"000000000000000000" and count(5 downto 3) /= "111" then
elsif dend(128 downto 57) = x"000000000000000000" and count(6 downto 3) /= "0111" then
-- consume 8 bits of zeroes in one cycle
dend <= dend(119 downto 0) & x"00";
dend <= dend(120 downto 0) & x"00";
quot <= quot(55 downto 0) & x"00";
count <= count + 8;
else
dend <= dend(126 downto 0) & '0';
dend <= dend(127 downto 0) & '0';
quot <= quot(62 downto 0) & '0';
count <= count + 1;
end if;
@ -126,7 +110,7 @@ begin
d_out.write_reg_nr <= write_reg;

if is_modulus = '1' then
result <= dend(127 downto 64);
result <= dend(128 downto 65);
else
result <= quot;
end if;
@ -135,15 +119,40 @@ begin
else
sresult <= result;
end if;
did_ovf <= '0';
if is_32bit = '0' then
did_ovf <= overflow or (is_signed and (sresult(63) xor neg_result));
elsif is_signed = '1' then
if overflow = '1' or
(sresult(63 downto 31) /= x"00000000" & '0' and
sresult(63 downto 31) /= x"ffffffff" & '1') then
did_ovf <= '1';
end if;
else
did_ovf <= overflow or (or (sresult(63 downto 32)));
end if;
if did_ovf = '1' then
d_out.write_reg_data <= (others => '0');
elsif (is_32bit = '1') and (is_modulus = '0') then
-- 32-bit divisions set the top 32 bits of the result to 0
d_out.write_reg_data <= x"00000000" & sresult(31 downto 0);
else
d_out.write_reg_data <= sresult;
end if;

if count(6) = '1' then
if count = "1000000" then
d_out.valid <= '1';
d_out.write_reg_enable <= '1';
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";
if (did_ovf = '1') or (or (sresult) = '0') then
d_out.write_cr_data <= x"20000000";
elsif (sresult(63) = '1') and not ((is_32bit = '1') and (is_modulus = '0')) then
d_out.write_cr_data <= x"80000000";
else
d_out.write_cr_data <= x"40000000";
end if;
end if;
end if;
end process;

108
divider_tb.vhdl
Unescape Escape View File

@ -35,6 +35,8 @@ begin
variable si: std_ulogic_vector(15 downto 0);
variable d128: std_ulogic_vector(127 downto 0);
variable q128: std_ulogic_vector(127 downto 0);
variable q64: std_ulogic_vector(63 downto 0);
variable rem32: std_ulogic_vector(31 downto 0);
begin
rst <= '1';
wait for clk_period;
@ -55,7 +57,7 @@ begin

d1.valid <= '0';

for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -79,7 +81,7 @@ begin

d1.valid <= '0';

for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -113,7 +115,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -121,13 +123,14 @@ begin
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := (others => '0');
if rb /= x"0000000000000000" and (ra /= x"8000000000000000" or rb /= x"ffffffffffffffff") then
behave_rt := ppc_divd(ra, rb);
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 if;
end loop;
end loop;
end loop;
@ -148,7 +151,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -156,13 +159,14 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
behave_rt := ppc_divdu(ra, rb);
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 if;
end loop;
end loop;
end loop;
@ -184,7 +188,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -192,18 +196,19 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
d128 := ra & x"0000000000000000";
q128 := std_ulogic_vector(signed(d128) / signed(rb));
if q128(127 downto 63) = x"0000000000000000" & '0' or
q128(127 downto 63) = x"ffffffffffffffff" & '1' then
behave_rt := q128(63 downto 0);
end if;
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 if;
end if;
end loop;
end loop;
end loop;
@ -225,7 +230,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -233,15 +238,16 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if unsigned(rb) > unsigned(ra) then
d128 := ra & x"0000000000000000";
q128 := std_ulogic_vector(unsigned(d128) / unsigned(rb));
behave_rt := q128(63 downto 0);
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 if;
end loop;
end loop;
end loop;
@ -264,7 +270,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -272,13 +278,14 @@ begin
end loop;
assert d2.valid = '1';

if rb /= x"0000000000000000" then
behave_rt := (others => '0');
if rb /= x"0000000000000000" and (ra /= x"ffffffff80000000" or rb /= x"ffffffffffffffff") then
behave_rt := ppc_divw(ra, rb);
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divw";
end if;
end loop;
end loop;
end loop;
@ -301,7 +308,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -309,13 +316,14 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
behave_rt := ppc_divwu(ra, rb);
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divwu";
end if;
end loop;
end loop;
end loop;
@ -338,7 +346,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -346,16 +354,18 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
behave_rt := std_ulogic_vector(signed(ra) / signed(rb));
if behave_rt(63 downto 31) = x"00000000" & '0' or
behave_rt(63 downto 31) = x"ffffffff" & '1' then
assert behave_rt(31 downto 0) = d2.write_reg_data(31 downto 0)
q64 := std_ulogic_vector(signed(ra) / signed(rb));
if q64(63 downto 31) = x"00000000" & '0' or
q64(63 downto 31) = x"ffffffff" & '1' then
behave_rt := x"00000000" & q64(31 downto 0);
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divwe";
end if;
end if;
end loop;
end loop;
end loop;
@ -378,7 +388,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -386,13 +396,14 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if unsigned(rb(31 downto 0)) > unsigned(ra(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)
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for divweu";
end if;
end loop;
end loop;
end loop;
@ -416,7 +427,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -424,13 +435,14 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
behave_rt := std_ulogic_vector(signed(ra) rem signed(rb));
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 if;
end loop;
end loop;
end loop;
@ -454,7 +466,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -462,13 +474,14 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
behave_rt := std_ulogic_vector(unsigned(ra) rem unsigned(rb));
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 if;
end loop;
end loop;
end loop;
@ -492,7 +505,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -500,13 +513,19 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
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)
rem32 := std_ulogic_vector(signed(ra(31 downto 0)) rem signed(rb(31 downto 0)));
if rem32(31) = '0' then
behave_rt := x"00000000" & rem32;
else
behave_rt := x"ffffffff" & rem32;
end if;
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for modsw";
end if;
end loop;
end loop;
end loop;
@ -530,7 +549,7 @@ begin
wait for clk_period;

d1.valid <= '0';
for j in 0 to 65 loop
for j in 0 to 66 loop
wait for clk_period;
if d2.valid = '1' then
exit;
@ -538,13 +557,14 @@ begin
end loop;
assert d2.valid = '1';

behave_rt := (others => '0');
if rb /= x"0000000000000000" then
behave_rt := x"00000000" & std_ulogic_vector(unsigned(ra(31 downto 0)) rem unsigned(rb(31 downto 0)));
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('0', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
assert ppc_cmpi('1', behave_rt, x"0000") & x"0000000" = d2.write_cr_data
report "bad CR setting for moduw";
end if;
end loop;
end loop;
end loop;

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