author | Rich Felker <dalias@aerifal.cx> | 2012年03月13日 01:17:53 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2012年03月13日 01:17:53 -0400 |
commit | b69f695acedd4ce2798ef9ea28d834ceccc789bd (patch) | |
tree | eafd98b9b75160210f3295ac074d699f863d958e /src/math/frexp.c | |
parent | d46cf2e14cc4df7cc75e77d7009fcb6df1f48a33 (diff) | |
download | musl-b69f695acedd4ce2798ef9ea28d834ceccc789bd.tar.gz |
-rw-r--r-- | src/math/frexp.c | 23 |
diff --git a/src/math/frexp.c b/src/math/frexp.c new file mode 100644 index 00000000..27b6266e --- /dev/null +++ b/src/math/frexp.c @@ -0,0 +1,23 @@ +#include <math.h> +#include <stdint.h> + +double frexp(double x, int *e) +{ + union { double d; uint64_t i; } y = { x }; + int ee = y.i>>52 & 0x7ff; + + if (!ee) { + if (x) { + x = frexp(x*0x1p64, e); + *e -= 64; + } else *e = 0; + return x; + } else if (ee == 0x7ff) { + return x; + } + + *e = ee - 0x3fe; + y.i &= 0x800fffffffffffffull; + y.i |= 0x3fe0000000000000ull; + return y.d; +} |