annotate src/libm/s_copysign.c @ 3631:76667e288846

Revert r5463: Alpha blend "correctness" patch. Sam says: "We should revert this. I applied it in 1.3 and then fixed it for correctness."
author Ryan C. Gordon <icculus@icculus.org>
date Sun, 10 Jan 2010 08:59:25 +0000
parents dc1eb82ffdaa
children
rev   line source
2756
a98604b691c8 Expanded the libm support and put it into a separate directory.
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1 /* @(#)s_copysign.c 5.1 93/09/24 */
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2 /*
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3 * ====================================================
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4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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5 *
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6 * Developed at SunPro, a Sun Microsystems, Inc. business.
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7 * Permission to use, copy, modify, and distribute this
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8 * software is freely granted, provided that this notice
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9 * is preserved.
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10 * ====================================================
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11 */
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12
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13 #if defined(LIBM_SCCS) && !defined(lint)
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dc1eb82ffdaa Von: Thomas Zimmermann
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14 static const char rcsid[] =
2756
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15 "$NetBSD: s_copysign.c,v 1.8 1995/05/10 20:46:57 jtc Exp $";
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16 #endif
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17
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18 /*
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19 * copysign(double x, double y)
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20 * copysign(x,y) returns a value with the magnitude of x and
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21 * with the sign bit of y.
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22 */
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23
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24 #include "math.h"
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25 #include "math_private.h"
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26
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27 libm_hidden_proto(copysign)
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28 #ifdef __STDC__
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29 double copysign(double x, double y)
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30 #else
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31 double copysign(x, y)
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32 double x, y;
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33 #endif
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34 {
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35 u_int32_t hx, hy;
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36 GET_HIGH_WORD(hx, x);
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37 GET_HIGH_WORD(hy, y);
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38 SET_HIGH_WORD(x, (hx & 0x7fffffff) | (hy & 0x80000000));
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39 return x;
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40 }
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41
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42 libm_hidden_def(copysign)