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authorUlrich Drepper <drepper@redhat.com>1999-04-29 18:28:07 +0000
committerUlrich Drepper <drepper@redhat.com>1999-04-29 18:28:07 +0000
commit9943472996fdf9b881550ee75673aae0a080e214 (patch)
tree95429db2a47fa3081ee3f1cf7d92e585ad0bdbd3 /string
parent8a40ed68071594e64a381859d6d4302a9e7dd7bf (diff)
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Update.
* string/bits/string2.h: Add more memset optimizations.
Diffstat (limited to 'string')
-rw-r--r--string/bits/string2.h62
1 files changed, 59 insertions, 3 deletions
diff --git a/string/bits/string2.h b/string/bits/string2.h
index 3de175d0a8..d9ed80b3b5 100644
--- a/string/bits/string2.h
+++ b/string/bits/string2.h
@@ -94,9 +94,65 @@ __STRING2_COPY_TYPE (8);
/* Set N bytes of S to C. */
#ifndef _HAVE_STRING_ARCH_memset
# define memset(s, c, n) \
- (__extension__ (__builtin_constant_p (c) && (c) == '\0' \
- ? ({ void *__s = (s); __bzero (__s, n); __s; }) \
- : memset (s, c, n)))
+ (__extension__ (__builtin_constant_p (n) && (n) <= 16 \
+ ? (__builtin_constant_p (c) \
+ ? __memset_gc (s, (c) * 0x01010101, n) \
+ : __memset_gc (s, (n) == 1 ? (c) : (c) * 0x01010101, n)) \
+ : (__builtin_constant_p (c) && (c) == '\0' \
+ ? ({ void *__s = (s); __bzero (__s, n); __s; }) \
+ : memset (s, c, n))))
+
+#define __memset_gc(s, c, n) \
+ ({ void *__s = (s); \
+ __uint32_t *__ts = (__uint32_t *) __s; \
+ \
+ /* This `switch' statement will be removed at compile-time. */ \
+ switch (n) \
+ { \
+ case 15: \
+ *__ts++ = c; \
+ case 11: \
+ *__ts++ = c; \
+ case 7: \
+ *__ts++ = c; \
+ case 3: \
+ *((__uint16_t *) __ts)++ = c; \
+ *((__uint8_t *) __ts) = c; \
+ break; \
+ \
+ case 14: \
+ *__ts++ = c; \
+ case 10: \
+ *__ts++ = c; \
+ case 6: \
+ *__ts++ = c; \
+ case 2: \
+ *((__uint16_t *) __ts) = c; \
+ break; \
+ \
+ case 13: \
+ *__ts++ = c; \
+ case 9: \
+ *__ts++ = c; \
+ case 5: \
+ *__ts++ = c; \
+ case 1: \
+ *((__uint8_t *) __ts) = c; \
+ break; \
+ \
+ case 16: \
+ *__ts++ = c; \
+ case 12: \
+ *__ts++ = c; \
+ case 8: \
+ *__ts++ = c; \
+ case 4: \
+ *__ts = c; \
+ case 0: \
+ break; \
+ } \
+ \
+ __s; })
#endif