The floatx80 remainder implementation sometimes returns the numerator unchanged when the denominator is sufficiently larger than the numerator. But if the value to be returned unchanged is a pseudo-denormal, that is incorrect. Fix it to normalize the numerator in that case.
Signed-off-by: Joseph Myers <jos...@codesourcery.com> Reviewed-by: Richard Henderson <richard.hender...@linaro.org> --- fpu/softfloat.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 091847beb9..9d43868e4c 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -5691,7 +5691,7 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod, float_status *status) { bool aSign, zSign; - int32_t aExp, bExp, expDiff; + int32_t aExp, bExp, expDiff, aExpOrig; uint64_t aSig0, aSig1, bSig; uint64_t q, term0, term1, alternateASig0, alternateASig1; @@ -5700,7 +5700,7 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod, return floatx80_default_nan(status); } aSig0 = extractFloatx80Frac( a ); - aExp = extractFloatx80Exp( a ); + aExpOrig = aExp = extractFloatx80Exp( a ); aSign = extractFloatx80Sign( a ); bSig = extractFloatx80Frac( b ); bExp = extractFloatx80Exp( b ); @@ -5715,6 +5715,13 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod, if ((uint64_t)(bSig << 1)) { return propagateFloatx80NaN(a, b, status); } + if (aExp == 0 && aSig0 >> 63) { + /* + * Pseudo-denormal argument must be returned in normalized + * form. + */ + return packFloatx80(aSign, 1, aSig0); + } return a; } if ( bExp == 0 ) { @@ -5734,7 +5741,16 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod, expDiff = aExp - bExp; aSig1 = 0; if ( expDiff < 0 ) { - if ( mod || expDiff < -1 ) return a; + if ( mod || expDiff < -1 ) { + if (aExp == 1 && aExpOrig == 0) { + /* + * Pseudo-denormal argument must be returned in + * normalized form. + */ + return packFloatx80(aSign, aExp, aSig0); + } + return a; + } shift128Right( aSig0, 0, 1, &aSig0, &aSig1 ); expDiff = 0; } -- 2.17.1 -- Joseph S. Myers jos...@codesourcery.com