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Diffstat (limited to 'src/math/__expo2f.c')
| -rw-r--r-- | src/math/__expo2f.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/math/__expo2f.c b/src/math/__expo2f.c index 5163e418..538eb09c 100644 --- a/src/math/__expo2f.c +++ b/src/math/__expo2f.c @@ -5,12 +5,13 @@ static const int k = 235; static const float kln2 = 0x1.45c778p+7f; /* expf(x)/2 for x >= log(FLT_MAX), slightly better than 0.5f*expf(x/2)*expf(x/2) */ -float __expo2f(float x) +float __expo2f(float x, float sign) { float scale; /* note that k is odd and scale*scale overflows */ SET_FLOAT_WORD(scale, (uint32_t)(0x7f + k/2) << 23); /* exp(x - k ln2) * 2**(k-1) */ - return expf(x - kln2) * scale * scale; + /* in directed rounding correct sign before rounding or overflow is important */ + return expf(x - kln2) * (sign * scale) * scale; } |