sysdeps/libm-i387/s_isinfl.c

   1 /*
   2  * Written by J.T. Conklin <jtc@netbsd.org>.
   3  * Change for long double by Ulrich Drepper <drepper@cygnus.com>.
   4  * Intel i387 specific version.
   5  * Public domain.
   6  */
   7
   8 #if defined(LIBM_SCCS) && !defined(lint)
   9 static char rcsid[] = "$NetBSD: $";
  10 #endif
  11
  12 /*
  13  * isinfl(x) returns 1 if x is inf, -1 if x is -inf, else 0;
  14  * no branching!
  15  */
  16
  17 #include "math.h"
  18 #include "math_private.h"
  19
  20 #ifdef __STDC__
  21         int __isinfl(long double x)
  22 #else
  23         int __isinfl(x)
  24         long double x;
  25 #endif
  26 {
  27         int32_t se,hx,lx;
  28         GET_LDOUBLE_WORDS(se,hx,lx,x);
  29         /* This additional ^ 0x80000000 is necessary because in Intel's
  30            internal representation of the implicit one is explicit.  */
  31         lx |= (hx ^ 0x80000000) | ((se & 0x7fff) ^ 0x7fff);
  32         lx |= -lx;
  33         se &= 0x8000;
  34         return ~(lx >> 31) & (1 - (se >> 14));
  35 }
  36 weak_alias (__isinfl, isinfl)