69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* These math functions are taken from newlib-nano-2, the newlib/libm/math
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* directory, available from https://github.com/32bitmicro/newlib-nano-2.
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*
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* Appropriate copyright headers are reproduced below.
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*/
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/* kf_cos.c -- float version of k_cos.c
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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static const float
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#else
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static float
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#endif
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one = 1.0000000000e+00, /* 0x3f800000 */
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C1 = 4.1666667908e-02, /* 0x3d2aaaab */
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C2 = -1.3888889225e-03, /* 0xbab60b61 */
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C3 = 2.4801587642e-05, /* 0x37d00d01 */
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C4 = -2.7557314297e-07, /* 0xb493f27c */
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C5 = 2.0875723372e-09, /* 0x310f74f6 */
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C6 = -1.1359647598e-11; /* 0xad47d74e */
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#ifdef __STDC__
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float __kernel_cosf(float x, float y)
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#else
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float __kernel_cosf(x, y)
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float x,y;
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#endif
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{
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float a,hz,z,r,qx;
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__int32_t ix;
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GET_FLOAT_WORD(ix,x);
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ix &= 0x7fffffff; /* ix = |x|'s high word*/
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if(ix<0x32000000) { /* if x < 2**27 */
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if(((int)x)==0) return one; /* generate inexact */
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}
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z = x*x;
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r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
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if(ix < 0x3e99999a) /* if |x| < 0.3 */
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return one - ((float)0.5*z - (z*r - x*y));
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else {
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if(ix > 0x3f480000) { /* x > 0.78125 */
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qx = (float)0.28125;
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} else {
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SET_FLOAT_WORD(qx,ix-0x01000000); /* x/4 */
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}
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hz = (float)0.5*z-qx;
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a = one-qx;
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return a - (hz - (z*r-x*y));
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}
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}
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