linux_dsm_epyc7002/arch/s390/include/asm/string.h
Heiko Carstens b4623d4e5b s390: provide memmove implementation
Provide an s390 specific memmove implementation which is faster than
the generic implementation which copies byte-wise.

For non-destructive (as defined by the mvc instruction) memmove
operations the following table compares the old default implementation
versus the new s390 specific implementation:

size     old   new
   1     1ns   8ns
   2     2ns   8ns
   4     4ns   8ns
   8     7ns   8ns
  16    17ns   8ns
  32    35ns   8ns
  64    65ns   9ns
 128   146ns  10ns
 256   298ns  11ns
 512   537ns  11ns
1024  1193ns  19ns
2048  2405ns  36ns

So only for very small sizes the old implementation is faster. For
overlapping memmoves, where the mvc instruction can't be used, the new
implementation is as slow as the old one.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-12-12 12:11:32 +01:00

144 lines
3.7 KiB
C

/*
* S390 version
* Copyright IBM Corp. 1999
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
*/
#ifndef _S390_STRING_H_
#define _S390_STRING_H_
#ifndef _LINUX_TYPES_H
#include <linux/types.h>
#endif
#define __HAVE_ARCH_MEMCHR /* inline & arch function */
#define __HAVE_ARCH_MEMCMP /* arch function */
#define __HAVE_ARCH_MEMCPY /* gcc builtin & arch function */
#define __HAVE_ARCH_MEMMOVE /* gcc builtin & arch function */
#define __HAVE_ARCH_MEMSCAN /* inline & arch function */
#define __HAVE_ARCH_MEMSET /* gcc builtin & arch function */
#define __HAVE_ARCH_STRCAT /* inline & arch function */
#define __HAVE_ARCH_STRCMP /* arch function */
#define __HAVE_ARCH_STRCPY /* inline & arch function */
#define __HAVE_ARCH_STRLCAT /* arch function */
#define __HAVE_ARCH_STRLCPY /* arch function */
#define __HAVE_ARCH_STRLEN /* inline & arch function */
#define __HAVE_ARCH_STRNCAT /* arch function */
#define __HAVE_ARCH_STRNCPY /* arch function */
#define __HAVE_ARCH_STRNLEN /* inline & arch function */
#define __HAVE_ARCH_STRRCHR /* arch function */
#define __HAVE_ARCH_STRSTR /* arch function */
/* Prototypes for non-inlined arch strings functions. */
extern int memcmp(const void *, const void *, size_t);
extern void *memcpy(void *, const void *, size_t);
extern void *memset(void *, int, size_t);
extern void *memmove(void *, const void *, size_t);
extern int strcmp(const char *,const char *);
extern size_t strlcat(char *, const char *, size_t);
extern size_t strlcpy(char *, const char *, size_t);
extern char *strncat(char *, const char *, size_t);
extern char *strncpy(char *, const char *, size_t);
extern char *strrchr(const char *, int);
extern char *strstr(const char *, const char *);
#undef __HAVE_ARCH_STRCHR
#undef __HAVE_ARCH_STRNCHR
#undef __HAVE_ARCH_STRNCMP
#undef __HAVE_ARCH_STRPBRK
#undef __HAVE_ARCH_STRSEP
#undef __HAVE_ARCH_STRSPN
#if !defined(IN_ARCH_STRING_C)
static inline void *memchr(const void * s, int c, size_t n)
{
register int r0 asm("0") = (char) c;
const void *ret = s + n;
asm volatile(
"0: srst %0,%1\n"
" jo 0b\n"
" jl 1f\n"
" la %0,0\n"
"1:"
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc");
return (void *) ret;
}
static inline void *memscan(void *s, int c, size_t n)
{
register int r0 asm("0") = (char) c;
const void *ret = s + n;
asm volatile(
"0: srst %0,%1\n"
" jo 0b\n"
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc");
return (void *) ret;
}
static inline char *strcat(char *dst, const char *src)
{
register int r0 asm("0") = 0;
unsigned long dummy;
char *ret = dst;
asm volatile(
"0: srst %0,%1\n"
" jo 0b\n"
"1: mvst %0,%2\n"
" jo 1b"
: "=&a" (dummy), "+a" (dst), "+a" (src)
: "d" (r0), "0" (0) : "cc", "memory" );
return ret;
}
static inline char *strcpy(char *dst, const char *src)
{
register int r0 asm("0") = 0;
char *ret = dst;
asm volatile(
"0: mvst %0,%1\n"
" jo 0b"
: "+&a" (dst), "+&a" (src) : "d" (r0)
: "cc", "memory");
return ret;
}
static inline size_t strlen(const char *s)
{
register unsigned long r0 asm("0") = 0;
const char *tmp = s;
asm volatile(
"0: srst %0,%1\n"
" jo 0b"
: "+d" (r0), "+a" (tmp) : : "cc");
return r0 - (unsigned long) s;
}
static inline size_t strnlen(const char * s, size_t n)
{
register int r0 asm("0") = 0;
const char *tmp = s;
const char *end = s + n;
asm volatile(
"0: srst %0,%1\n"
" jo 0b"
: "+a" (end), "+a" (tmp) : "d" (r0) : "cc");
return end - s;
}
#else /* IN_ARCH_STRING_C */
void *memchr(const void * s, int c, size_t n);
void *memscan(void *s, int c, size_t n);
char *strcat(char *dst, const char *src);
char *strcpy(char *dst, const char *src);
size_t strlen(const char *s);
size_t strnlen(const char * s, size_t n);
#endif /* !IN_ARCH_STRING_C */
#endif /* __S390_STRING_H_ */