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| author | Jens Arnold <amiconn@rockbox.org> | 2006-08-08 23:15:17 +0000 |
|---|---|---|
| committer | Jens Arnold <amiconn@rockbox.org> | 2006-08-08 23:15:17 +0000 |
| commit | e72820f5e2c96a9218be21986e3e22d26adb6cd8 (patch) | |
| tree | b08c08cba03ce68d18bca37542c98f4dd24cdb8a | |
| parent | b888fb25315ba1dd24b5bdb95246e0912bb76dca (diff) | |
| download | rockbox-e72820f5e2c96a9218be21986e3e22d26adb6cd8.tar.gz rockbox-e72820f5e2c96a9218be21986e3e22d26adb6cd8.zip | |
Slightly optimised range_limit() for arm targets.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10494 a1c6a512-1295-4272-9138-f99709370657
| -rw-r--r-- | apps/plugins/jpeg.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/apps/plugins/jpeg.c b/apps/plugins/jpeg.c index 5ecd394d26..9a32a8c6ca 100644 --- a/apps/plugins/jpeg.c +++ b/apps/plugins/jpeg.c | |||
| @@ -200,12 +200,11 @@ INLINE unsigned range_limit(int value) | |||
| 200 | ); | 200 | ); |
| 201 | return value; | 201 | return value; |
| 202 | #elif defined(CPU_ARM) | 202 | #elif defined(CPU_ARM) |
| 203 | asm ( | 203 | asm ( /* Note: Uses knowledge that only the low byte of the result is used */ |
| 204 | "adds %[v], %[v], #128\n" /* value += 128 */ | 204 | "add %[v], %[v], #128 \n" /* value += 128 */ |
| 205 | "movmi %[v], #0 \n" /* clip to 0 if negative result */ | 205 | "cmp %[v], #255 \n" /* out of range 0..255? */ |
| 206 | "cmp %[v], #255 \n" /* did we exceed 255? */ | 206 | "mvnhi %[v], %[v], asr #31 \n" /* yes: set all bits to ~(sign_bit) */ |
| 207 | "movgt %[v], #255 \n" /* yes, clip to limit */ | 207 | : /* outputs */ |
| 208 | : | ||
| 209 | [v]"+r"(value) | 208 | [v]"+r"(value) |
| 210 | ); | 209 | ); |
| 211 | return value; | 210 | return value; |