sysdeps/ieee754/flt-32/s_cosf.c

   1 /* s_cosf.c -- float version of s_cos.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_cosf.c,v 1.4 1995/05/10 20:47:03 jtc Exp $";
  18 #endif
  19
  20 #include <errno.h>
  21 #include <math.h>
  22 #include <math_private.h>
  23
  24 #ifndef COSF
  25 # define COSF_FUNC __cosf
  26 #else
  27 # define COSF_FUNC COSF
  28 #endif
  29
  30 float COSF_FUNC(float x)
  31 {
  32         float y[2],z=0.0;
  33         int32_t n,ix;
  34
  35         GET_FLOAT_WORD(ix,x);
  36
  37     /* |x| ~< pi/4 */
  38         ix &= 0x7fffffff;
  39         if(ix <= 0x3f490fd8) return __kernel_cosf(x,z);
  40
  41     /* cos(Inf or NaN) is NaN */
  42         else if (ix>=0x7f800000) {
  43           if (ix == 0x7f800000)
  44             __set_errno (EDOM);
  45           return x-x;
  46         }
  47
  48     /* argument reduction needed */
  49         else {
  50             n = __ieee754_rem_pio2f(x,y);
  51             switch(n&3) {
  52                 case 0: return  __kernel_cosf(y[0],y[1]);
  53                 case 1: return -__kernel_sinf(y[0],y[1],1);
  54                 case 2: return -__kernel_cosf(y[0],y[1]);
  55                 default:
  56                         return  __kernel_sinf(y[0],y[1],1);
  57             }
  58         }
  59 }
  60
  61 #ifndef COSF
  62 weak_alias (__cosf, cosf)
  63 #endif