Mercurial > sdl-ios-xcode
comparison src/video/SDL_blit.h @ 91:e85e03f195b4
From: "Markus F.X.J. Oberhumer"
Subject: SDL CVS patches
below you will find some small patches against the
current SDL CVS.
It adresses these things:
1) Use "&" instead of "%" in some cases. For negative
signed integers (x % 8) is not always (x & 7),
and the compiler can produce slightly faster
code when using "&" here.
2) Some const issues.
| author | Sam Lantinga <slouken@lokigames.com> |
|---|---|
| date | Sat, 07 Jul 2001 20:20:17 +0000 |
| parents | 74212992fb08 |
| children | 2dc7252dc53e |
comparison
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| 90:ee1f71c10889 | 91:e85e03f195b4 |
|---|---|
| 382 #ifdef USE_DUFFS_LOOP | 382 #ifdef USE_DUFFS_LOOP |
| 383 | 383 |
| 384 /* 8-times unrolled loop */ | 384 /* 8-times unrolled loop */ |
| 385 #define DUFFS_LOOP8(pixel_copy_increment, width) \ | 385 #define DUFFS_LOOP8(pixel_copy_increment, width) \ |
| 386 { int n = (width+7)/8; \ | 386 { int n = (width+7)/8; \ |
| 387 switch (width % 8) { \ | 387 switch (width & 7) { \ |
| 388 case 0: do { pixel_copy_increment; \ | 388 case 0: do { pixel_copy_increment; \ |
| 389 case 7: pixel_copy_increment; \ | 389 case 7: pixel_copy_increment; \ |
| 390 case 6: pixel_copy_increment; \ | 390 case 6: pixel_copy_increment; \ |
| 391 case 5: pixel_copy_increment; \ | 391 case 5: pixel_copy_increment; \ |
| 392 case 4: pixel_copy_increment; \ | 392 case 4: pixel_copy_increment; \ |
| 398 } | 398 } |
| 399 | 399 |
| 400 /* 4-times unrolled loop */ | 400 /* 4-times unrolled loop */ |
| 401 #define DUFFS_LOOP4(pixel_copy_increment, width) \ | 401 #define DUFFS_LOOP4(pixel_copy_increment, width) \ |
| 402 { int n = (width+3)/4; \ | 402 { int n = (width+3)/4; \ |
| 403 switch (width % 4) { \ | 403 switch (width & 3) { \ |
| 404 case 0: do { pixel_copy_increment; \ | 404 case 0: do { pixel_copy_increment; \ |
| 405 case 3: pixel_copy_increment; \ | 405 case 3: pixel_copy_increment; \ |
| 406 case 2: pixel_copy_increment; \ | 406 case 2: pixel_copy_increment; \ |
| 407 case 1: pixel_copy_increment; \ | 407 case 1: pixel_copy_increment; \ |
| 408 } while ( --n > 0 ); \ | 408 } while ( --n > 0 ); \ |