diff options
| -rw-r--r-- | fpu/softfloat-parts.c.inc | 80 | ||||
| -rw-r--r-- | fpu/softfloat.c | 206 |
2 files changed, 156 insertions, 130 deletions
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc index 2eb7bb96b3..b9094768db 100644 --- a/fpu/softfloat-parts.c.inc +++ b/fpu/softfloat-parts.c.inc @@ -938,3 +938,83 @@ static void partsN(uint_to_float)(FloatPartsN *p, uint64_t a, p->frac_hi = a << shift; } } + +/* + * Float min/max. + */ +static FloatPartsN *partsN(minmax)(FloatPartsN *a, FloatPartsN *b, + float_status *s, int flags) +{ + int ab_mask = float_cmask(a->cls) | float_cmask(b->cls); + int a_exp, b_exp, cmp; + + if (unlikely(ab_mask & float_cmask_anynan)) { + /* + * For minnum/maxnum, if one operand is a QNaN, and the other + * operand is numerical, then return numerical argument. + */ + if ((flags & minmax_isnum) + && !(ab_mask & float_cmask_snan) + && (ab_mask & ~float_cmask_qnan)) { + return is_nan(a->cls) ? b : a; + } + return parts_pick_nan(a, b, s); + } + + a_exp = a->exp; + b_exp = b->exp; + + if (unlikely(ab_mask != float_cmask_normal)) { + switch (a->cls) { + case float_class_normal: + break; + case float_class_inf: + a_exp = INT16_MAX; + break; + case float_class_zero: + a_exp = INT16_MIN; + break; + default: + g_assert_not_reached(); + break; + } + switch (b->cls) { + case float_class_normal: + break; + case float_class_inf: + b_exp = INT16_MAX; + break; + case float_class_zero: + b_exp = INT16_MIN; + break; + default: + g_assert_not_reached(); + break; + } + } + + /* Compare magnitudes. */ + cmp = a_exp - b_exp; + if (cmp == 0) { + cmp = frac_cmp(a, b); + } + + /* + * Take the sign into account. + * For ismag, only do this if the magnitudes are equal. + */ + if (!(flags & minmax_ismag) || cmp == 0) { + if (a->sign != b->sign) { + /* For differing signs, the negative operand is less. */ + cmp = a->sign ? -1 : 1; + } else if (a->sign) { + /* For two negative operands, invert the magnitude comparison. */ + cmp = -cmp; + } + } + + if (flags & minmax_ismin) { + cmp = -cmp; + } + return cmp < 0 ? b : a; +} diff --git a/fpu/softfloat.c b/fpu/softfloat.c index db14bd09aa..ef750e1e95 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -482,6 +482,15 @@ enum { float_cmask_anynan = float_cmask_qnan | float_cmask_snan, }; +/* Flags for parts_minmax. */ +enum { + /* Set for minimum; clear for maximum. */ + minmax_ismin = 1, + /* Set for the IEEE 754-2008 minNum() and maxNum() operations. */ + minmax_isnum = 2, + /* Set for the IEEE 754-2008 minNumMag() and minNumMag() operations. */ + minmax_ismag = 4, +}; /* Simple helpers for checking if, or what kind of, NaN we have */ static inline __attribute__((unused)) bool is_nan(FloatClass c) @@ -865,6 +874,14 @@ static void parts128_uint_to_float(FloatParts128 *p, uint64_t a, #define parts_uint_to_float(P, I, Z, S) \ PARTS_GENERIC_64_128(uint_to_float, P)(P, I, Z, S) +static FloatParts64 *parts64_minmax(FloatParts64 *a, FloatParts64 *b, + float_status *s, int flags); +static FloatParts128 *parts128_minmax(FloatParts128 *a, FloatParts128 *b, + float_status *s, int flags); + +#define parts_minmax(A, B, S, F) \ + PARTS_GENERIC_64_128(minmax, A)(A, B, S, F) + /* * Helper functions for softfloat-parts.c.inc, per-size operations. */ @@ -3258,145 +3275,74 @@ float128 uint64_to_float128(uint64_t a, float_status *status) return float128_round_pack_canonical(&p, status); } -/* Float Min/Max */ -/* min() and max() functions. These can't be implemented as - * 'compare and pick one input' because that would mishandle - * NaNs and +0 vs -0. - * - * minnum() and maxnum() functions. These are similar to the min() - * and max() functions but if one of the arguments is a QNaN and - * the other is numerical then the numerical argument is returned. - * SNaNs will get quietened before being returned. - * minnum() and maxnum correspond to the IEEE 754-2008 minNum() - * and maxNum() operations. min() and max() are the typical min/max - * semantics provided by many CPUs which predate that specification. - * - * minnummag() and maxnummag() functions correspond to minNumMag() - * and minNumMag() from the IEEE-754 2008. +/* + * Minimum and maximum */ -static FloatParts64 minmax_floats(FloatParts64 a, FloatParts64 b, bool ismin, - bool ieee, bool ismag, float_status *s) -{ - if (unlikely(is_nan(a.cls) || is_nan(b.cls))) { - if (ieee) { - /* Takes two floating-point values `a' and `b', one of - * which is a NaN, and returns the appropriate NaN - * result. If either `a' or `b' is a signaling NaN, - * the invalid exception is raised. - */ - if (is_snan(a.cls) || is_snan(b.cls)) { - return *parts_pick_nan(&a, &b, s); - } else if (is_nan(a.cls) && !is_nan(b.cls)) { - return b; - } else if (is_nan(b.cls) && !is_nan(a.cls)) { - return a; - } - } - return *parts_pick_nan(&a, &b, s); - } else { - int a_exp, b_exp; - switch (a.cls) { - case float_class_normal: - a_exp = a.exp; - break; - case float_class_inf: - a_exp = INT_MAX; - break; - case float_class_zero: - a_exp = INT_MIN; - break; - default: - g_assert_not_reached(); - break; - } - switch (b.cls) { - case float_class_normal: - b_exp = b.exp; - break; - case float_class_inf: - b_exp = INT_MAX; - break; - case float_class_zero: - b_exp = INT_MIN; - break; - default: - g_assert_not_reached(); - break; - } +static float16 float16_minmax(float16 a, float16 b, float_status *s, int flags) +{ + FloatParts64 pa, pb, *pr; - if (ismag && (a_exp != b_exp || a.frac != b.frac)) { - bool a_less = a_exp < b_exp; - if (a_exp == b_exp) { - a_less = a.frac < b.frac; - } - return a_less ^ ismin ? b : a; - } + float16_unpack_canonical(&pa, a, s); + float16_unpack_canonical(&pb, b, s); + pr = parts_minmax(&pa, &pb, s, flags); - if (a.sign == b.sign) { - bool a_less = a_exp < b_exp; - if (a_exp == b_exp) { - a_less = a.frac < b.frac; - } - return a.sign ^ a_less ^ ismin ? b : a; - } else { - return a.sign ^ ismin ? b : a; - } - } + return float16_round_pack_canonical(pr, s); } -#define MINMAX(sz, name, ismin, isiee, ismag) \ -float ## sz float ## sz ## _ ## name(float ## sz a, float ## sz b, \ - float_status *s) \ -{ \ - FloatParts64 pa, pb, pr; \ - float ## sz ## _unpack_canonical(&pa, a, s); \ - float ## sz ## _unpack_canonical(&pb, b, s); \ - pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \ - return float ## sz ## _round_pack_canonical(&pr, s); \ -} - -MINMAX(16, min, true, false, false) -MINMAX(16, minnum, true, true, false) -MINMAX(16, minnummag, true, true, true) -MINMAX(16, max, false, false, false) -MINMAX(16, maxnum, false, true, false) -MINMAX(16, maxnummag, false, true, true) - -MINMAX(32, min, true, false, false) -MINMAX(32, minnum, true, true, false) -MINMAX(32, minnummag, true, true, true) -MINMAX(32, max, false, false, false) -MINMAX(32, maxnum, false, true, false) -MINMAX(32, maxnummag, false, true, true) - -MINMAX(64, min, true, false, false) -MINMAX(64, minnum, true, true, false) -MINMAX(64, minnummag, true, true, true) -MINMAX(64, max, false, false, false) -MINMAX(64, maxnum, false, true, false) -MINMAX(64, maxnummag, false, true, true) - -#undef MINMAX - -#define BF16_MINMAX(name, ismin, isiee, ismag) \ -bfloat16 bfloat16_ ## name(bfloat16 a, bfloat16 b, float_status *s) \ -{ \ - FloatParts64 pa, pb, pr; \ - bfloat16_unpack_canonical(&pa, a, s); \ - bfloat16_unpack_canonical(&pb, b, s); \ - pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \ - return bfloat16_round_pack_canonical(&pr, s); \ +static bfloat16 bfloat16_minmax(bfloat16 a, bfloat16 b, + float_status *s, int flags) +{ + FloatParts64 pa, pb, *pr; + + bfloat16_unpack_canonical(&pa, a, s); + bfloat16_unpack_canonical(&pb, b, s); + pr = parts_minmax(&pa, &pb, s, flags); + + return bfloat16_round_pack_canonical(pr, s); } -BF16_MINMAX(min, true, false, false) -BF16_MINMAX(minnum, true, true, false) -BF16_MINMAX(minnummag, true, true, true) -BF16_MINMAX(max, false, false, false) -BF16_MINMAX(maxnum, false, true, false) -BF16_MINMAX(maxnummag, false, true, true) +static float32 float32_minmax(float32 a, float32 b, float_status *s, int flags) +{ + FloatParts64 pa, pb, *pr; + + float32_unpack_canonical(&pa, a, s); + float32_unpack_canonical(&pb, b, s); + pr = parts_minmax(&pa, &pb, s, flags); + + return float32_round_pack_canonical(pr, s); +} + +static float64 float64_minmax(float64 a, float64 b, float_status *s, int flags) +{ + FloatParts64 pa, pb, *pr; + + float64_unpack_canonical(&pa, a, s); + float64_unpack_canonical(&pb, b, s); + pr = parts_minmax(&pa, &pb, s, flags); + + return float64_round_pack_canonical(pr, s); +} + +#define MINMAX_1(type, name, flags) \ + type type##_##name(type a, type b, float_status *s) \ + { 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_2(float16) +MINMAX_2(bfloat16) +MINMAX_2(float32) +MINMAX_2(float64) -#undef BF16_MINMAX +#undef MINMAX_1 +#undef MINMAX_2 /* Floating point compare */ static FloatRelation compare_floats(FloatParts64 a, FloatParts64 b, bool is_quiet, |