diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2011-03-11 08:12:25 +0000 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2011-04-03 17:19:38 +0200 |
| commit | 274f1b041e0d550750cc6992092ad0197b2c5320 (patch) | |
| tree | 122064602cf7e564f761314b4fa903ae39c83adf /fpu/softfloat.c | |
| parent | 79c18be7dfe660ab48f9f535e6cabd38c9f1d73b (diff) | |
| download | qemu-274f1b041e0d550750cc6992092ad0197b2c5320.tar.gz | |
softfloat: Add float*_min() and float*_max() functions
Add min and max operations to softfloat. This allows us to implement
propagation of NaNs and handling of negative zero correctly (unlike
the approach of having target helper routines return one of the operands
based on the result of a comparison op).
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Diffstat (limited to 'fpu/softfloat.c')
| -rw-r--r-- | fpu/softfloat.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 08e4ae03d9..03fb9487bd 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -6057,6 +6057,55 @@ int float128_compare_quiet( float128 a, float128 b STATUS_PARAM ) return float128_compare_internal(a, b, 1 STATUS_VAR); } +/* min() and max() functions. These can't be implemented as + * 'compare and pick one input' because that would mishandle + * NaNs and +0 vs -0. + */ +#define MINMAX(s, nan_exp) \ +INLINE float ## s float ## s ## _minmax(float ## s a, float ## s b, \ + int ismin STATUS_PARAM ) \ +{ \ + flag aSign, bSign; \ + uint ## s ## _t av, bv; \ + a = float ## s ## _squash_input_denormal(a STATUS_VAR); \ + b = float ## s ## _squash_input_denormal(b STATUS_VAR); \ + if (float ## s ## _is_any_nan(a) || \ + float ## s ## _is_any_nan(b)) { \ + return propagateFloat ## s ## NaN(a, b STATUS_VAR); \ + } \ + aSign = extractFloat ## s ## Sign(a); \ + bSign = extractFloat ## s ## Sign(b); \ + av = float ## s ## _val(a); \ + bv = float ## s ## _val(b); \ + 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 STATUS_PARAM) \ +{ \ + return float ## s ## _minmax(a, b, 1 STATUS_VAR); \ +} \ + \ +float ## s float ## s ## _max(float ## s a, float ## s b STATUS_PARAM) \ +{ \ + return float ## s ## _minmax(a, b, 0 STATUS_VAR); \ +} + +MINMAX(32, 0xff) +MINMAX(64, 0x7ff) + + /* Multiply A by 2 raised to the power N. */ float32 float32_scalbn( float32 a, int n STATUS_PARAM ) { |