1 /*
2 * Public domain.
3 */
4
5 /*
6 * isinf(x) returns 1 is x is inf, -1 if x is -inf, else 0;
7 * no branching!
8 */
9
10 #include <math.h>
11 #include <math_private.h>
12 #include <ldbl-classify-compat.h>
13 #include <shlib-compat.h>
14
15 int
__isinf(double x)16 __isinf (double x)
17 {
18 int64_t ix;
19 EXTRACT_WORDS64 (ix,x);
20 int64_t t = ix & UINT64_C (0x7fffffffffffffff);
21 t ^= UINT64_C (0x7ff0000000000000);
22 t |= -t;
23 return ~(t >> 63) & (ix >> 62);
24 }
25 hidden_def (__isinf)
26 weak_alias (__isinf, isinf)
27 #ifdef NO_LONG_DOUBLE
28 # if LDBL_CLASSIFY_COMPAT && SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
29 compat_symbol (libc, __isinf, __isinfl, GLIBC_2_0);
30 # endif
31 weak_alias (__isinf, isinfl)
32 #endif
33