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Subject[patch/s390 44/46] use compiler builtin versions of strlen/strcpy/strcat
From: Heiko Carstens <heiko.carstens@de.ibm.com>

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>
---

arch/s390/include/asm/string.h | 12 ++++++++++++
arch/s390/lib/string.c | 12 ++++++++++++
2 files changed, 24 insertions(+)

Index: quilt-2.6/arch/s390/include/asm/string.h
===================================================================
--- quilt-2.6.orig/arch/s390/include/asm/string.h
+++ quilt-2.6/arch/s390/include/asm/string.h
@@ -84,6 +84,7 @@ static inline void *memscan(void *s, int

static inline char *strcat(char *dst, const char *src)
{
+#if __GNUC__ < 4
register int r0 asm("0") = 0;
unsigned long dummy;
char *ret = dst;
@@ -96,10 +97,14 @@ static inline char *strcat(char *dst, co
: "=&a" (dummy), "+a" (dst), "+a" (src)
: "d" (r0), "0" (0) : "cc", "memory" );
return ret;
+#else
+ return __builtin_strcat(dst, src);
+#endif
}

static inline char *strcpy(char *dst, const char *src)
{
+#if __GNUC__ < 4
register int r0 asm("0") = 0;
char *ret = dst;

@@ -109,10 +114,14 @@ static inline char *strcpy(char *dst, co
: "+&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 +130,9 @@ static inline size_t strlen(const char *
" 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)
Index: quilt-2.6/arch/s390/lib/string.c
===================================================================
--- quilt-2.6.orig/arch/s390/lib/string.c
+++ quilt-2.6/arch/s390/lib/string.c
@@ -44,7 +44,11 @@ static inline char *__strnend(const char
*/
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);

@@ -132,6 +140,7 @@ EXPORT_SYMBOL(strncpy);
*/
char *strcat(char *dest, const char *src)
{
+#if __GNUC__ < 4
register int r0 asm("0") = 0;
unsigned long dummy;
char *ret = dest;
@@ -143,6 +152,9 @@ char *strcat(char *dest, const char *src
: "=&a" (dummy), "+a" (dest), "+a" (src)
: "d" (r0), "0" (0UL) : "cc", "memory" );
return ret;
+#else
+ return __builtin_strcat(dest, src);
+#endif
}
EXPORT_SYMBOL(strcat);

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



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