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[S390] use compiler builtin versions of strlen/strcpy/strcat

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Use builtin variants if gcc 4 or newer is used to compile the kernel.
Generates better code than the asm variants.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2009-03-26 15:24:37 +01:00 committed by Martin Schwidefsky
parent 504665a914
commit 1edad85b16
2 changed files with 16 additions and 0 deletions
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8
arch/s390/include/asm/string.h
View file

@ -100,6 +100,7 @@ static inline char *strcat(char *dst, const char *src)
static inline char *strcpy(char *dst, const char *src)
{
#if __GNUC__ < 4
register int r0 asm("0") = 0;
char *ret = dst;
@ -109,10 +110,14 @@ static inline char *strcpy(char *dst, const char *src)
: "+&a" (dst), "+&a" (src) : "d" (r0)
: "cc", "memory");
return ret;
#else
return __builtin_strcpy(dst, src);
#endif
}
static inline size_t strlen(const char *s)
{
#if __GNUC__ < 4
register unsigned long r0 asm("0") = 0;
const char *tmp = s;
@ -121,6 +126,9 @@ static inline size_t strlen(const char *s)
" jo 0b"
: "+d" (r0), "+a" (tmp) : : "cc");
return r0 - (unsigned long) s;
#else
return __builtin_strlen(s);
#endif
}
static inline size_t strnlen(const char * s, size_t n)

8
arch/s390/lib/string.c
View file

@ -44,7 +44,11 @@ static inline char *__strnend(const char *s, size_t n)
*/
size_t strlen(const char *s)
{
#if __GNUC__ < 4
return __strend(s) - s;
#else
return __builtin_strlen(s);
#endif
}
EXPORT_SYMBOL(strlen);
@ -70,6 +74,7 @@ EXPORT_SYMBOL(strnlen);
*/
char *strcpy(char *dest, const char *src)
{
#if __GNUC__ < 4
register int r0 asm("0") = 0;
char *ret = dest;
@ -78,6 +83,9 @@ char *strcpy(char *dest, const char *src)
: "+&a" (dest), "+&a" (src) : "d" (r0)
: "cc", "memory" );
return ret;
#else
return __builtin_strcpy(dest, src);
#endif
}
EXPORT_SYMBOL(strcpy);