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