lib/libm/src/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 #include <sys/cdefs.h>
  17 #if defined(LIBM_SCCS) && !defined(lint)
  18 __RCSID("$NetBSD: s_sinf.c,v 1.8 2007/08/20 16:01:39 drochner Exp $");
  19 #endif
  20
  21 #include "namespace.h"
  22 #include "math.h"
  23 #include "math_private.h"
  24
  25 #if 0 /* notyet */
  26 #ifdef __weak_alias
  27 __weak_alias(sinf, _sinf)
  28 #endif
  29 #endif
  30
  31 float
  32 sinf(float x)
  33 {
  34         float y[2],z=0.0;
  35         int32_t n, ix;
  36
  37         GET_FLOAT_WORD(ix,x);
  38
  39     /* |x| ~< pi/4 */
  40         ix &= 0x7fffffff;
  41         if(ix <= 0x3f490fd8) return __kernel_sinf(x,z,0);
  42
  43     /* sin(Inf or NaN) is NaN */
  44         else if (ix>=0x7f800000) return x-x;
  45
  46     /* argument reduction needed */
  47         else {
  48             n = __ieee754_rem_pio2f(x,y);
  49             switch(n&3) {
  50                 case 0: return  __kernel_sinf(y[0],y[1],1);
  51                 case 1: return  __kernel_cosf(y[0],y[1]);
  52                 case 2: return -__kernel_sinf(y[0],y[1],1);
  53                 default:
  54                         return -__kernel_cosf(y[0],y[1]);
  55             }
  56         }
  57 }