diff options
Diffstat (limited to 'fpu/softfloat.c')
| -rw-r--r-- | fpu/softfloat.c | 227 |
1 files changed, 120 insertions, 107 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index a07b8556b0..7a53c36da4 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -1663,6 +1663,126 @@ float64 uint16_to_float64(uint16_t a, float_status *status) return uint64_to_float64(a, 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. + */ +static FloatParts minmax_floats(FloatParts a, FloatParts 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 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 pick_nan(a, b, s); + } else { + int a_exp, b_exp; + bool a_sign, b_sign; + + 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; + } + + a_sign = a.sign; + b_sign = b.sign; + if (ismag) { + a_sign = b_sign = 0; + } + + 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; + } + } +} + +#define MINMAX(sz, name, ismin, isiee, ismag) \ +float ## sz float ## sz ## _ ## name(float ## sz a, float ## sz b, \ + float_status *s) \ +{ \ + FloatParts pa = float ## sz ## _unpack_canonical(a, s); \ + FloatParts pb = float ## sz ## _unpack_canonical(b, s); \ + FloatParts 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 + /* Multiply A by 2 raised to the power N. */ static FloatParts scalbn_decomposed(FloatParts a, int n, float_status *s) { @@ -6912,113 +7032,6 @@ int float128_compare_quiet(float128 a, float128 b, float_status *status) return float128_compare_internal(a, b, 1, status); } -/* 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. - * 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. - */ -#define MINMAX(s) \ -static inline float ## s float ## s ## _minmax(float ## s a, float ## s b, \ - int ismin, int isieee, \ - int ismag, \ - float_status *status) \ -{ \ - flag aSign, bSign; \ - uint ## s ## _t av, bv, aav, abv; \ - a = float ## s ## _squash_input_denormal(a, status); \ - b = float ## s ## _squash_input_denormal(b, status); \ - if (float ## s ## _is_any_nan(a) || \ - float ## s ## _is_any_nan(b)) { \ - if (isieee) { \ - if (float ## s ## _is_quiet_nan(a, status) && \ - !float ## s ##_is_any_nan(b)) { \ - return b; \ - } else if (float ## s ## _is_quiet_nan(b, status) && \ - !float ## s ## _is_any_nan(a)) { \ - return a; \ - } \ - } \ - return propagateFloat ## s ## NaN(a, b, status); \ - } \ - aSign = extractFloat ## s ## Sign(a); \ - bSign = extractFloat ## s ## Sign(b); \ - av = float ## s ## _val(a); \ - bv = float ## s ## _val(b); \ - if (ismag) { \ - aav = float ## s ## _abs(av); \ - abv = float ## s ## _abs(bv); \ - if (aav != abv) { \ - if (ismin) { \ - return (aav < abv) ? a : b; \ - } else { \ - return (aav < abv) ? b : a; \ - } \ - } \ - } \ - if (aSign != bSign) { \ - if (ismin) { \ - return aSign ? a : b; \ - } else { \ - return aSign ? b : a; \ - } \ - } else { \ - if (ismin) { \ - return (aSign ^ (av < bv)) ? a : b; \ - } else { \ - return (aSign ^ (av < bv)) ? b : a; \ - } \ - } \ -} \ - \ -float ## s float ## s ## _min(float ## s a, float ## s b, \ - float_status *status) \ -{ \ - return float ## s ## _minmax(a, b, 1, 0, 0, status); \ -} \ - \ -float ## s float ## s ## _max(float ## s a, float ## s b, \ - float_status *status) \ -{ \ - return float ## s ## _minmax(a, b, 0, 0, 0, status); \ -} \ - \ -float ## s float ## s ## _minnum(float ## s a, float ## s b, \ - float_status *status) \ -{ \ - return float ## s ## _minmax(a, b, 1, 1, 0, status); \ -} \ - \ -float ## s float ## s ## _maxnum(float ## s a, float ## s b, \ - float_status *status) \ -{ \ - return float ## s ## _minmax(a, b, 0, 1, 0, status); \ -} \ - \ -float ## s float ## s ## _minnummag(float ## s a, float ## s b, \ - float_status *status) \ -{ \ - return float ## s ## _minmax(a, b, 1, 1, 1, status); \ -} \ - \ -float ## s float ## s ## _maxnummag(float ## s a, float ## s b, \ - float_status *status) \ -{ \ - return float ## s ## _minmax(a, b, 0, 1, 1, status); \ -} - -MINMAX(32) -MINMAX(64) - - floatx80 floatx80_scalbn(floatx80 a, int n, float_status *status) { flag aSign; |