1 /* 2 * This file is part of the MicroPython project, http://micropython.org/ 3 * 4 * These math functions are taken from newlib-nano-2, the newlib/libm/math 5 * directory, available from https://github.com/32bitmicro/newlib-nano-2. 6 * 7 * Appropriate copyright headers are reproduced below. 8 */ 9 10 /* kf_cos.c -- float version of k_cos.c 11 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 12 */ 13 14 /* 15 * ==================================================== 16 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 17 * 18 * Developed at SunPro, a Sun Microsystems, Inc. business. 19 * Permission to use, copy, modify, and distribute this 20 * software is freely granted, provided that this notice 21 * is preserved. 22 * ==================================================== 23 */ 24 25 #include "fdlibm.h" 26 27 #ifdef __STDC__ 28 static const float 29 #else 30 static float 31 #endif 32 one = 1.0000000000e+00f, /* 0x3f800000 */ 33 C1 = 4.1666667908e-02f, /* 0x3d2aaaab */ 34 C2 = -1.3888889225e-03f, /* 0xbab60b61 */ 35 C3 = 2.4801587642e-05f, /* 0x37d00d01 */ 36 C4 = -2.7557314297e-07f, /* 0xb493f27c */ 37 C5 = 2.0875723372e-09f, /* 0x310f74f6 */ 38 C6 = -1.1359647598e-11f; /* 0xad47d74e */ 39 40 #ifdef __STDC__ __kernel_cosf(float x,float y)41 float __kernel_cosf(float x, float y) 42 #else 43 float __kernel_cosf(x, y) 44 float x,y; 45 #endif 46 { 47 float a,hz,z,r,qx; 48 __int32_t ix; 49 GET_FLOAT_WORD(ix,x); 50 ix &= 0x7fffffff; /* ix = |x|'s high word*/ 51 if(ix<0x32000000) { /* if x < 2**27 */ 52 if(((int)x)==0) return one; /* generate inexact */ 53 } 54 z = x*x; 55 r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6))))); 56 if(ix < 0x3e99999a) /* if |x| < 0.3 */ 57 return one - ((float)0.5*z - (z*r - x*y)); 58 else { 59 if(ix > 0x3f480000) { /* x > 0.78125 */ 60 qx = (float)0.28125; 61 } else { 62 SET_FLOAT_WORD(qx,ix-0x01000000); /* x/4 */ 63 } 64 hz = (float)0.5*z-qx; 65 a = one-qx; 66 return a - (hz - (z*r-x*y)); 67 } 68 } 69