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  1. /* sf_cos.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. #include "fdlibm.h"
  17.  
  18. #ifdef __STDC__
  19. static const float one=1.0;
  20. #else
  21. static float one=1.0;
  22. #endif
  23.  
  24. #ifdef __STDC__
  25.         float cosf(float x)
  26. #else
  27.         float cosf(x)
  28.         float x;
  29. #endif
  30. {
  31.         float y[2],z=0.0;
  32.         __int32_t n,ix;
  33.  
  34.         GET_FLOAT_WORD(ix,x);
  35.  
  36.     /* |x| ~< pi/4 */
  37.         ix &= 0x7fffffff;
  38.         if(ix <= 0x3f490fd8) return __kernel_cosf(x,z);
  39.  
  40.     /* cos(Inf or NaN) is NaN */
  41.         else if (!FLT_UWORD_IS_FINITE(ix)) return x-x;
  42.  
  43.     /* argument reduction needed */
  44.         else {
  45.             n = __ieee754_rem_pio2f(x,y);
  46.             switch(n&3) {
  47.                 case 0: return  __kernel_cosf(y[0],y[1]);
  48.                 case 1: return -__kernel_sinf(y[0],y[1],1);
  49.                 case 2: return -__kernel_cosf(y[0],y[1]);
  50.                 default:
  51.                         return  __kernel_sinf(y[0],y[1],1);
  52.             }
  53.         }
  54. }
  55.  
  56. #ifdef _DOUBLE_IS_32BITS
  57.  
  58. #ifdef __STDC__
  59.         double cos(double x)
  60. #else
  61.         double cos(x)
  62.         double x;
  63. #endif
  64. {
  65.         return (double) cosf((float) x);
  66. }
  67.  
  68. #endif /* defined(_DOUBLE_IS_32BITS) */
  69.