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Commit 1edad85b authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

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



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

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 504665a9

arch/s390/include/asm/string.h

+8 −0
Original line number Diff line number Diff line
@@ -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)

arch/s390/lib/string.c

+8 −0
Original line number Diff line number Diff line
@@ -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);