1 #include <math.h>
2 #include <errno.h>
3 #include <limits.h>
4 #include <math_private.h>
5 #include <fenv.h>
6 
7 #if _GL_HAS_BUILTIN_ILOGB
8 int
M_DECL_FUNC(__ilogb)9 M_DECL_FUNC (__ilogb) (FLOAT x)
10 {
11   int r;
12   /* Check for exceptional cases.  */
13   if (! M_SUF(__builtin_test_dc_ilogb) (x, 0x7f))
14     r = M_SUF (__builtin_ilogb) (x);
15   else
16     /* Fallback to the generic ilogb if x is NaN, Inf or subnormal.  */
17     r = M_SUF (__ieee754_ilogb) (x);
18   if (__builtin_expect (r == FP_ILOGB0, 0)
19       || __builtin_expect (r == FP_ILOGBNAN, 0)
20       || __builtin_expect (r == INT_MAX, 0))
21     {
22       __set_errno (EDOM);
23       __feraiseexcept (FE_INVALID);
24     }
25   return r;
26 }
27 declare_mgen_alias (__ilogb, ilogb)
28 #else
29 #include <math/w_ilogb_template.c>
30 #endif
31