Andrew Rossignol | d61f9eb | 2016-05-27 12:30:37 -0700 | [diff] [blame] | 1 | /* kf_cos.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 "fdlibm.h" |
| 17 | |
| 18 | #ifdef __STDC__ |
| 19 | static const float |
| 20 | #else |
| 21 | static float |
| 22 | #endif |
| 23 | one = 1.0000000000e+00, /* 0x3f800000 */ |
| 24 | C1 = 4.1666667908e-02, /* 0x3d2aaaab */ |
| 25 | C2 = -1.3888889225e-03, /* 0xbab60b61 */ |
| 26 | C3 = 2.4801587642e-05, /* 0x37d00d01 */ |
| 27 | C4 = -2.7557314297e-07, /* 0xb493f27c */ |
| 28 | C5 = 2.0875723372e-09, /* 0x310f74f6 */ |
| 29 | C6 = -1.1359647598e-11; /* 0xad47d74e */ |
| 30 | |
| 31 | #ifdef __STDC__ |
| 32 | float __kernel_cosf(float x, float y) |
| 33 | #else |
| 34 | float __kernel_cosf(x, y) |
| 35 | float x,y; |
| 36 | #endif |
| 37 | { |
| 38 | float a,hz,z,r,qx; |
| 39 | __int32_t ix; |
| 40 | GET_FLOAT_WORD(ix,x); |
| 41 | ix &= 0x7fffffff; /* ix = |x|'s high word*/ |
| 42 | if(ix<0x32000000) { /* if x < 2**27 */ |
| 43 | if(((int)x)==0) return one; /* generate inexact */ |
| 44 | } |
| 45 | z = x*x; |
| 46 | r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6))))); |
| 47 | if(ix < 0x3e99999a) /* if |x| < 0.3 */ |
| 48 | return one - ((float)0.5*z - (z*r - x*y)); |
| 49 | else { |
| 50 | if(ix > 0x3f480000) { /* x > 0.78125 */ |
| 51 | qx = (float)0.28125; |
| 52 | } else { |
| 53 | SET_FLOAT_WORD(qx,ix-0x01000000); /* x/4 */ |
| 54 | } |
| 55 | hz = (float)0.5*z-qx; |
| 56 | a = one-qx; |
| 57 | return a - (hz - (z*r-x*y)); |
| 58 | } |
| 59 | } |