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| author | Chih-Min Chao <chihmin.chao@sifive.com> | 2021-10-22 00:08:45 +0800 |
|---|---|---|
| committer | Alistair Francis <alistair.francis@wdc.com> | 2021-10-29 16:55:45 +1000 |
| commit | 0e9030376e1a8eb6d15cb5e69dffa09a6ff16b92 (patch) | |
| tree | 62971887576fbe63cded429e387ce35127ffa79b /fpu/softfloat.c | |
| parent | 50d160876414e91e51ac718ac6edea6dbadf4694 (diff) | |
| download | qemu-0e9030376e1a8eb6d15cb5e69dffa09a6ff16b92.zip qemu-0e9030376e1a8eb6d15cb5e69dffa09a6ff16b92.tar.gz qemu-0e9030376e1a8eb6d15cb5e69dffa09a6ff16b92.tar.bz2 | |
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 <chihmin.chao@sifive.com>
Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211021160847.2748577-2-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Diffstat (limited to 'fpu/softfloat.c')
| -rw-r--r-- | fpu/softfloat.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 6e769f9..9a28720 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) |