toolchain/gcc/newlib/libm/math/sf_cos.c

   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) */