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symfpu: floatWithStatusFlags

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Now with verified muladd exceptions.
This commit is contained in:
Krystine Sherwin 2026-01-21 18:32:07 +13:00
parent 5c99ff204b
commit 88e6305849
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4 changed files with 37 additions and 65 deletions
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25
tests/symfpu/edges.sv
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@ -166,16 +166,26 @@ module edges();
assign rounded_000 = '0;
`endif
`ifdef RTP
wire c_muladd_turning = c_sig == '0;
`elsif RTN
wire c_muladd_turning = c_sig < 23'h400000;
`elsif RTZ
wire c_muladd_turning = c_sig == '0;
`else // RNA || RNE (default)
wire c_muladd_turning = c_sig <= 23'h200000;
`endif
always @* begin
if (a_nan || b_nan || c_nan) begin
// input NaN = output NaN
assert (o_nan);
// NaN inputs give NaN outputs, do not raise exceptions (unless signaling NV)
// assert (!DZ);
// assert (!OF);
// assert (!UF);
// assert (!NX);
assert (!DZ);
assert (!OF);
assert (!UF);
assert (!NX);
end
if (a_snan)
@ -226,8 +236,8 @@ module edges();
`endif
if (UF)
// output = subnormal
assert (o_subnorm);
// output = subnormal or zero
assert (o_subnorm || o_zero);
if (o_inf && !OF)
// a non-overflowing infinity is exact
@ -354,7 +364,6 @@ module edges();
// normal multiplication, overflow addition
if (a == 31'h5f400000 && b == a && c == 32'h7f400000) begin
assert (OF);
assert (o_inf); // assuming RNE
end
// if multiplication overflows, addition can bring it back in range
if (a == 32'hc3800001 && b == 32'h7b800000 && !c_special) begin
@ -364,7 +373,7 @@ module edges();
else if (c_exp <= 8'he7)
// addend can't be too small
assert (OF);
else if (c_exp == 8'he8 && c_sig <= 22'h200000)
else if (c_exp == 8'he8 && c_muladd_turning)
// this is just the turning point for this particular value
assert (OF);
else

2
tests/symfpu/run-test.sh
View file

@ -37,6 +37,6 @@ prove_op add "-DADD -DADDSUB -DADDS"
prove_op sub "-DSUB -DADDSUB -DADDS"
prove_op mul "-DMUL -DMULS"
prove_op div "-DDIV"
# prove_op muladd "-DMULADD -DMULS -DADDS"
prove_op muladd "-DMULADD -DMULS -DADDS"
generate_mk --yosys-scripts