zig/lib/libc/musl/src/math/__fpclassify.c
Andrew Kelley 49d1a4c562 move lib dirs to lib subdir
also start prefering NtDll API. so far:
 * NtQueryInformationFile
 * NtClose

adds a performance workaround for windows unicode conversion. but that
should probably be removed before merging
2019-07-15 17:54:50 -04:00

12 lines
258 B
C
Vendored

#include <math.h>
#include <stdint.h>
int __fpclassify(double x)
{
union {double f; uint64_t i;} u = {x};
int e = u.i>>52 & 0x7ff;
if (!e) return u.i<<1 ? FP_SUBNORMAL : FP_ZERO;
if (e==0x7ff) return u.i<<12 ? FP_NAN : FP_INFINITE;
return FP_NORMAL;
}