From 0e9030376e1a8eb6d15cb5e69dffa09a6ff16b92 Mon Sep 17 00:00:00 2001 From: Chih-Min Chao Date: Fri, 22 Oct 2021 00:08:45 +0800 Subject: softfloat: add APIs to handle alternative sNaN propagation for fmax/fmin For "fmax/fmin ft0, ft1, ft2" and if one of the inputs is sNaN, The original logic: Return NaN and set invalid flag if ft1 == sNaN || ft2 == sNan. The alternative path: Set invalid flag if ft1 == sNaN || ft2 == sNaN. Return NaN only if ft1 == NaN && ft2 == NaN. The IEEE 754 spec allows both implementation and some architecture such as riscv choose different defintions in two spec versions. (riscv-spec-v2.2 use original version, riscv-spec-20191213 changes to alternative) Signed-off-by: Chih-Min Chao Signed-off-by: Frank Chang Reviewed-by: Richard Henderson Message-Id: <20211021160847.2748577-2-frank.chang@sifive.com> Signed-off-by: Alistair Francis --- fpu/softfloat.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) (limited to 'fpu/softfloat.c') diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 6e769f990c..9a28720d82 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -436,6 +436,11 @@ enum { minmax_isnum = 2, /* Set for the IEEE 754-2008 minNumMag() and minNumMag() operations. */ minmax_ismag = 4, + /* + * Set for the IEEE 754-2019 minimumNumber() and maximumNumber() + * operations. + */ + minmax_isnumber = 8, }; /* Simple helpers for checking if, or what kind of, NaN we have */ @@ -3927,12 +3932,14 @@ static float128 float128_minmax(float128 a, float128 b, { return type##_minmax(a, b, s, flags); } #define MINMAX_2(type) \ - MINMAX_1(type, max, 0) \ - MINMAX_1(type, maxnum, minmax_isnum) \ - MINMAX_1(type, maxnummag, minmax_isnum | minmax_ismag) \ - MINMAX_1(type, min, minmax_ismin) \ - MINMAX_1(type, minnum, minmax_ismin | minmax_isnum) \ - MINMAX_1(type, minnummag, minmax_ismin | minmax_isnum | minmax_ismag) + MINMAX_1(type, max, 0) \ + MINMAX_1(type, maxnum, minmax_isnum) \ + MINMAX_1(type, maxnummag, minmax_isnum | minmax_ismag) \ + MINMAX_1(type, maximum_number, minmax_isnumber) \ + MINMAX_1(type, min, minmax_ismin) \ + MINMAX_1(type, minnum, minmax_ismin | minmax_isnum) \ + MINMAX_1(type, minnummag, minmax_ismin | minmax_isnum | minmax_ismag) \ + MINMAX_1(type, minimum_number, minmax_ismin | minmax_isnumber) \ MINMAX_2(float16) MINMAX_2(bfloat16) -- cgit 1.4.1