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Changed 2 to 1 in FmaPreResultSubnorm logic, fixing issue 655 about multiply on f/fh. Not entirely confident this is the right change, but can't find any failures. See https://docs.google.com/document/d/1p7zb4Vvd1LMBLRgEpXjHyp7etCaFaiBVrBZJM8jediE/edit

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David Harris 2024-04-03 17:28:31 -07:00
parent ccd0e9cd0c
commit 499e4d6a6e
1 changed files with 10 additions and 10 deletions
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20
src/fpu/postproc/fmashiftcalc.sv
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@ -83,23 +83,23 @@ module fmashiftcalc import cvw::*; #(parameter cvw_t P) (
if (P.FPSIZES == 1) begin
logic Sum0LEZ, Sum0GEFL;
assign Sum0LEZ = PreNormSumExp[P.NE+1] | ~|PreNormSumExp;
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-2));
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-1)); // changed from -2 dh 4/3/24 for issue 655
assign FmaPreResultSubnorm = Sum0LEZ & Sum0GEFL & ~FmaSZero;
end else if (P.FPSIZES == 2) begin
logic Sum0LEZ, Sum0GEFL, Sum1LEZ, Sum1GEFL;
assign Sum0LEZ = PreNormSumExp[P.NE+1] | ~|PreNormSumExp;
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-2));
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-1)); // changed from -2 dh 4/3/24 for issue 655
assign Sum1LEZ = $signed(PreNormSumExp) <= $signed((P.NE+2)'(P.BIAS-P.BIAS1));
assign Sum1GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF1-2+P.BIAS-P.BIAS1)) | ~|PreNormSumExp;
assign Sum1GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF1-1+P.BIAS-P.BIAS1)) | ~|PreNormSumExp;
assign FmaPreResultSubnorm = (Fmt ? Sum0LEZ : Sum1LEZ) & (Fmt ? Sum0GEFL : Sum1GEFL) & ~FmaSZero;
end else if (P.FPSIZES == 3) begin
logic Sum0LEZ, Sum0GEFL, Sum1LEZ, Sum1GEFL, Sum2LEZ, Sum2GEFL;
assign Sum0LEZ = PreNormSumExp[P.NE+1] | ~|PreNormSumExp;
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-2));
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-1));
assign Sum1LEZ = $signed(PreNormSumExp) <= $signed((P.NE+2)'(P.BIAS-P.BIAS1));
assign Sum1GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF1-2+P.BIAS-P.BIAS1)) | ~|PreNormSumExp;
assign Sum1GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF1-1+P.BIAS-P.BIAS1)) | ~|PreNormSumExp;
assign Sum2LEZ = $signed(PreNormSumExp) <= $signed((P.NE+2)'(P.BIAS-P.BIAS2));
assign Sum2GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF2-2+P.BIAS-P.BIAS2)) | ~|PreNormSumExp;
assign Sum2GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF2-1+P.BIAS-P.BIAS2)) | ~|PreNormSumExp;
always_comb begin
case (Fmt)
P.FMT: FmaPreResultSubnorm = Sum0LEZ & Sum0GEFL; // & ~FmaSZero; // checking sum is not zero is harmless but turns out to be unnecessary
@ -111,13 +111,13 @@ module fmashiftcalc import cvw::*; #(parameter cvw_t P) (
end else if (P.FPSIZES == 4) begin
logic Sum0LEZ, Sum0GEFL, Sum1LEZ, Sum1GEFL, Sum2LEZ, Sum2GEFL, Sum3LEZ, Sum3GEFL;
assign Sum0LEZ = PreNormSumExp[P.NE+1] | ~|PreNormSumExp;
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-2));
assign Sum0GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.NF-1));
assign Sum1LEZ = $signed(PreNormSumExp) <= $signed((P.NE+2)'(P.BIAS-P.D_BIAS));
assign Sum1GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.D_NF-2+P.BIAS-P.D_BIAS)) | ~|PreNormSumExp;
assign Sum1GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.D_NF-1+P.BIAS-P.D_BIAS)) | ~|PreNormSumExp;
assign Sum2LEZ = $signed(PreNormSumExp) <= $signed((P.NE+2)'(P.BIAS-P.S_BIAS));
assign Sum2GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.S_NF-2+P.BIAS-P.S_BIAS)) | ~|PreNormSumExp;
assign Sum2GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.S_NF-1+P.BIAS-P.S_BIAS)) | ~|PreNormSumExp;
assign Sum3LEZ = $signed(PreNormSumExp) <= $signed((P.NE+2)'(P.BIAS-P.H_BIAS));
assign Sum3GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.H_NF-2+P.BIAS-P.H_BIAS)) | ~|PreNormSumExp;
assign Sum3GEFL = $signed(PreNormSumExp) >= $signed((P.NE+2)'(-P.H_NF-1+P.BIAS-P.H_BIAS)) | ~|PreNormSumExp;
always_comb begin
case (Fmt)
2'h3: FmaPreResultSubnorm = Sum0LEZ & Sum0GEFL & ~FmaSZero;