gonzui

    1: /* k_cosf.c -- float version of k_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 "math.h"
   17: #include "math_private.h"
   18: 
   19: static const float 
   20: one =  1.0000000000e+00, /* 0x3f800000 */
   21: C1  =  4.1666667908e-02, /* 0x3d2aaaab */
   22: C2  = -1.3888889225e-03, /* 0xbab60b61 */
   23: C3  =  2.4801587642e-05, /* 0x37d00d01 */
   24: C4  = -2.7557314297e-07, /* 0xb493f27c */
   25: C5  =  2.0875723372e-09, /* 0x310f74f6 */
   26: C6  = -1.1359647598e-11; /* 0xad47d74e */
   27: 
   28: float
   29: __kernel_cosf(float x, float y)
   30: {
   31:         float a,hz,z,r,qx;
   32:         int32_t ix;
   33:         GET_FLOAT_WORD(ix,x);
   34:         ix &= 0x7fffffff;                      /* ix = |x|'s high word*/
   35:         if(ix<0x32000000) {                    /* if x < 2**27 */
   36:             if(((int)x)==0) return one;                /* generate inexact */
   37:         }
   38:         z  = x*x;
   39:         r  = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
   40:         if(ix < 0x3e99999a)                    /* if |x| < 0.3 */ 
   41:             return one - ((float)0.5*z - (z*r - x*y));
   42:         else {
   43:             if(ix > 0x3f480000) {              /* x > 0.78125 */
   44:                 qx = (float)0.28125;
   45:             } else {
   46:                 SET_FLOAT_WORD(qx,ix-0x01000000);      /* x/4 */
   47:             }
   48:             hz = (float)0.5*z-qx;
   49:             a  = one-qx;
   50:             return a - (hz - (z*r-x*y));
   51:         }
   52: }