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(__memset_gc): Help generating better code in presence of the asm.

This commit is contained in:
Ulrich Drepper 1999-04-30 17:37:52 +00:00
parent ad8fa1c670
commit c5883607f5
1 changed files with 19 additions and 19 deletions
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38
sysdeps/i386/i486/bits/string.h
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@ -210,56 +210,56 @@ memcmp (__const void *__s1, __const void *__s2, size_t __n)
#define __memset_gc(s, c, n) \ #define __memset_gc(s, c, n) \
({ void *__s = (s); \ ({ void *__s = (s); \
unsigned int *__ts = (unsigned int *) __s; \ unsigned int *__ts = (unsigned int *) __s; \
unsigned char __c = (unsigned char) (c); \ unsigned int __c = ((unsigned char) (c)) * 0x01010101; \
\ \
/* We apply a trick here. `gcc' would implement the following \ /* We apply a trick here. `gcc' would implement the following \
assignments using absolute operands. But this uses to much \ assignments using absolute operands. But this uses to much \
memory (7, instead of 4 bytes). */ \ memory (7, instead of 4 bytes). */ \
if (n >= 5) \ if (n == 3 || n >= 5) \
__asm__ __volatile__ ("" : "=r" (__c) : "0" (__c)); \ __asm__ __volatile__ ("" : "=r" (__c) : "0" (__c)); \
\ \
/* This `switch' statement will be removed at compile-time. */ \ /* This `switch' statement will be removed at compile-time. */ \
switch (n) \ switch (n) \
{ \ { \
case 15: \ case 15: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 11: \ case 11: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 7: \ case 7: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 3: \ case 3: \
*((unsigned short int *) __ts)++ = __c * 0x0101; \ *((unsigned short int *) __ts)++ = (unsigned short int) __c; \
*((unsigned char *) __ts) = __c; \ *((unsigned char *) __ts) = (unsigned char) __c; \
break; \ break; \
\ \
case 14: \ case 14: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 10: \ case 10: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 6: \ case 6: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 2: \ case 2: \
*((unsigned short int *) __ts) = __c * 0x0101; \ *((unsigned short int *) __ts) = (unsigned short int) __c; \
break; \ break; \
\ \
case 13: \ case 13: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 9: \ case 9: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 5: \ case 5: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 1: \ case 1: \
*((unsigned char *) __ts) = __c; \ *((unsigned char *) __ts) = (unsigned char) __c; \
break; \ break; \
\ \
case 16: \ case 16: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 12: \ case 12: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 8: \ case 8: \
*__ts++ = __c * 0x01010101; \ *__ts++ = __c; \
case 4: \ case 4: \
*__ts = __c * 0x01010101; \ *__ts = __c; \
case 0: \ case 0: \
break; \ break; \
} \ } \