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comparison src/video/SDL_memops.h @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
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children cf2af46e9e2a
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1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id$";
26 #endif
27
28 #ifndef _SDL_memops_h
29 #define _SDL_memops_h
30
31 /* System dependent optimized memory manipulation routines:
32 */
33 #include <string.h>
34
35 #if defined(__GNUC__) && defined(i386)
36 /* Thanks to Brennan "Bas" Underwood, for the inspiration. :)
37 */
38 #define SDL_memcpy(dst, src, len) \
39 do { \
40 int u0, u1, u2; \
41 __asm__ __volatile__ ( \
42 "cld\n\t" \
43 "rep ; movsl\n\t" \
44 "testb $2,%b4\n\t" \
45 "je 1f\n\t" \
46 "movsw\n" \
47 "1:\ttestb $1,%b4\n\t" \
48 "je 2f\n\t" \
49 "movsb\n" \
50 "2:" \
51 : "=&c" (u0), "=&D" (u1), "=&S" (u2) \
52 : "0" ((unsigned)(len)/4), "q" (len), "1" (dst),"2" (src) \
53 : "memory" ); \
54 } while(0)
55
56 #define SDL_revcpy(dst, src, len) \
57 do { \
58 int u0, u1, u2; \
59 char *dstp = (char *)(dst); \
60 char *srcp = (char *)(src); \
61 int n = (len); \
62 if ( n >= 4 ) { \
63 __asm__ __volatile__ ( \
64 "std\n\t" \
65 "rep ; movsl\n\t" \
66 : "=&c" (u0), "=&D" (u1), "=&S" (u2) \
67 : "0" (n >> 2), \
68 "1" (dstp+(n-4)), "2" (srcp+(n-4)) \
69 : "memory" ); \
70 } \
71 switch (n & 3) { \
72 case 3: dstp[2] = srcp[2]; \
73 case 2: dstp[1] = srcp[1]; \
74 case 1: dstp[0] = srcp[0]; \
75 break; \
76 default: \
77 break; \
78 } \
79 } while(0)
80
81 #define SDL_memmove(dst, src, len) \
82 do { \
83 if ( (dst) < (src) ) { \
84 SDL_memcpy((dst), (src), (len)); \
85 } else { \
86 SDL_revcpy((dst), (src), (len)); \
87 } \
88 } while(0)
89
90 #define SDL_memset4(dst, val, len) \
91 do { \
92 int u0, u1, u2; \
93 __asm__ __volatile__ ( \
94 "cld\n\t" \
95 "rep ; stosl\n\t" \
96 : "=&D" (u0), "=&a" (u1), "=&c" (u2) \
97 : "0" (dst), "1" (val), "2" ((Uint32)(len)) \
98 : "memory" ); \
99 } while(0)
100
101 #endif /* GNU C and x86 */
102
103 /* If there are no optimized versions, define the normal versions */
104 #ifndef SDL_memcpy
105 #define SDL_memcpy(dst, src, len) memcpy(dst, src, len)
106 #endif
107 #ifndef SDL_revcpy
108 #define SDL_revcpy(dst, src, len) memmove(dst, src, len)
109 #endif
110 #ifndef SDL_memset4
111 #define SDL_memset4(dst, val, len) \
112 do { \
113 unsigned _count = (len); \
114 unsigned _n = (_count + 3) / 4; \
115 Uint32 *_p = (Uint32 *)(dst); \
116 Uint32 _val = (val); \
117 switch (_count % 4) { \
118 case 0: do { *_p++ = _val; \
119 case 3: *_p++ = _val; \
120 case 2: *_p++ = _val; \
121 case 1: *_p++ = _val; \
122 } while ( --_n ); \
123 } \
124 } while(0)
125 #endif
126
127 #endif /* _SDL_memops_h */