Mercurial > sdl-ios-xcode
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> |
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date | Sun, 10 Jan 2010 08:59:25 +0000 |
parents | dc1eb82ffdaa |
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rev | line source |
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2756
a98604b691c8
Expanded the libm support and put it into a separate directory.
Sam Lantinga <slouken@libsdl.org>
parents:
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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 |
a98604b691c8
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Sam Lantinga <slouken@libsdl.org>
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9 * is preserved. |
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10 * ==================================================== |
a98604b691c8
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Sam Lantinga <slouken@libsdl.org>
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11 */ |
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12 |
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13 #if defined(LIBM_SCCS) && !defined(lint) |
3162 | 14 static const char rcsid[] = |
2756
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Sam Lantinga <slouken@libsdl.org>
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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) |