sysdeps/libm-ieee754/s_sinf.c

   1 /* s_sinf.c -- float version of s_sin.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: s_sinf.c,v 1.4 1995/05/10 20:48:16 jtc Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 #ifdef __STDC__
  24         float __sinf(float x)
  25 #else
  26         float __sinf(x)
  27         float x;
  28 #endif
  29 {
  30         float y[2],z=0.0;
  31         int32_t n, ix;
  32
  33         GET_FLOAT_WORD(ix,x);
  34
  35     /* |x| ~< pi/4 */
  36         ix &= 0x7fffffff;
  37         if(ix <= 0x3f490fd8) return __kernel_sinf(x,z,0);
  38
  39     /* sin(Inf or NaN) is NaN */
  40         else if (ix>=0x7f800000) return x-x;
  41
  42     /* argument reduction needed */
  43         else {
  44             n = __ieee754_rem_pio2f(x,y);
  45             switch(n&3) {
  46                 case 0: return  __kernel_sinf(y[0],y[1],1);
  47                 case 1: return  __kernel_cosf(y[0],y[1]);
  48                 case 2: return -__kernel_sinf(y[0],y[1],1);
  49                 default:
  50                         return -__kernel_cosf(y[0],y[1]);
  51             }
  52         }
  53 }
  54 weak_alias (__sinf, sinf)