diff options
| -rw-r--r-- | src/math/fma.c | 2 | ||||
| -rw-r--r-- | src/math/fmaf.c | 12 | ||||
| -rw-r--r-- | src/math/fmal.c | 2 |
3 files changed, 14 insertions, 2 deletions
diff --git a/src/math/fma.c b/src/math/fma.c index 89def795..850a4a6c 100644 --- a/src/math/fma.c +++ b/src/math/fma.c @@ -441,6 +441,8 @@ double fma(double x, double y, double z) /* * There is no need to worry about double rounding in directed * rounding modes. + * TODO: underflow is not raised properly, example in downward rounding: + * fma(0x1.000000001p-1000, 0x1.000000001p-30, -0x1p-1066) */ fesetround(oround); adj = r.lo + xy.lo; diff --git a/src/math/fmaf.c b/src/math/fmaf.c index a1c7f4f8..745ee393 100644 --- a/src/math/fmaf.c +++ b/src/math/fmaf.c @@ -49,7 +49,14 @@ float fmaf(float x, float y, float z) (hr & 0x7ff00000) == 0x7ff00000 || /* NaN */ result - xy == z || /* exact */ fegetround() != FE_TONEAREST) /* not round-to-nearest */ - return (result); + { + /* + TODO: underflow is not raised correctly, example in + downward rouding: fmaf(0x1p-120f, 0x1p-120f, 0x1p-149f) + */ + z = result; + return z; + } /* * If result is inexact, and exactly halfway between two float values, @@ -63,5 +70,6 @@ float fmaf(float x, float y, float z) fesetround(FE_TONEAREST); if (result == adjusted_result) SET_LOW_WORD(adjusted_result, lr + 1); - return (adjusted_result); + z = adjusted_result; + return z; } diff --git a/src/math/fmal.c b/src/math/fmal.c index ccbe434d..87e30fcf 100644 --- a/src/math/fmal.c +++ b/src/math/fmal.c @@ -262,6 +262,8 @@ long double fmal(long double x, long double y, long double z) /* * There is no need to worry about double rounding in directed * rounding modes. + * TODO: underflow is not raised correctly, example in downward rounding: + * fmal(0x1.0000000001p-16000L, 0x1.0000000001p-400L, -0x1p-16440L) */ fesetround(oround); adj = r.lo + xy.lo; |