![Andi Kleen](/assets/img/avatar_default.png)
The compiler generally generates reasonable inline code for the simple cases and for the rest it's better for code size for them to be out of line. Also there they can be potentially optimized more in the future. In fact they probably should be in a .S file because they're all pure assembly, but that's for another day. Also some code style cleanup on them while I was on it (this seems to be the last untouched really early Linux code) This saves ~12k text for a defconfig kernel with gcc 4.1. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
277 lines
6.7 KiB
C
277 lines
6.7 KiB
C
#ifndef _I386_STRING_H_
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#define _I386_STRING_H_
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#ifdef __KERNEL__
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/* Let gcc decide wether to inline or use the out of line functions */
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#define __HAVE_ARCH_STRCPY
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extern char *strcpy(char *dest, const char *src);
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#define __HAVE_ARCH_STRNCPY
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extern char *strncpy(char *dest, const char *src, size_t count);
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#define __HAVE_ARCH_STRCAT
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extern char *strcat(char *dest, const char *src);
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#define __HAVE_ARCH_STRNCAT
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extern char *strncat(char *dest, const char *src, size_t count);
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#define __HAVE_ARCH_STRCMP
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extern int strcmp(const char *cs, const char *ct);
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#define __HAVE_ARCH_STRNCMP
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extern int strncmp(const char *cs, const char *ct, size_t count);
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#define __HAVE_ARCH_STRCHR
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extern char *strchr(const char *s, int c);
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#define __HAVE_ARCH_STRRCHR
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extern char *strrchr(const char *s, int c);
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#define __HAVE_ARCH_STRLEN
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extern size_t strlen(const char *s);
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static __always_inline void * __memcpy(void * to, const void * from, size_t n)
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{
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int d0, d1, d2;
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__asm__ __volatile__(
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"rep ; movsl\n\t"
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"movl %4,%%ecx\n\t"
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"andl $3,%%ecx\n\t"
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"jz 1f\n\t"
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"rep ; movsb\n\t"
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"1:"
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: "=&c" (d0), "=&D" (d1), "=&S" (d2)
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: "0" (n/4), "g" (n), "1" ((long) to), "2" ((long) from)
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: "memory");
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return (to);
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}
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/*
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* This looks ugly, but the compiler can optimize it totally,
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* as the count is constant.
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*/
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static __always_inline void * __constant_memcpy(void * to, const void * from, size_t n)
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{
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long esi, edi;
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if (!n) return to;
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#if 1 /* want to do small copies with non-string ops? */
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switch (n) {
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case 1: *(char*)to = *(char*)from; return to;
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case 2: *(short*)to = *(short*)from; return to;
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case 4: *(int*)to = *(int*)from; return to;
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#if 1 /* including those doable with two moves? */
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case 3: *(short*)to = *(short*)from;
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*((char*)to+2) = *((char*)from+2); return to;
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case 5: *(int*)to = *(int*)from;
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*((char*)to+4) = *((char*)from+4); return to;
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case 6: *(int*)to = *(int*)from;
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*((short*)to+2) = *((short*)from+2); return to;
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case 8: *(int*)to = *(int*)from;
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*((int*)to+1) = *((int*)from+1); return to;
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#endif
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}
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#endif
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esi = (long) from;
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edi = (long) to;
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if (n >= 5*4) {
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/* large block: use rep prefix */
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int ecx;
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__asm__ __volatile__(
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"rep ; movsl"
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: "=&c" (ecx), "=&D" (edi), "=&S" (esi)
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: "0" (n/4), "1" (edi),"2" (esi)
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: "memory"
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);
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} else {
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/* small block: don't clobber ecx + smaller code */
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if (n >= 4*4) __asm__ __volatile__("movsl"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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if (n >= 3*4) __asm__ __volatile__("movsl"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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if (n >= 2*4) __asm__ __volatile__("movsl"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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if (n >= 1*4) __asm__ __volatile__("movsl"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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}
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switch (n % 4) {
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/* tail */
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case 0: return to;
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case 1: __asm__ __volatile__("movsb"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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return to;
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case 2: __asm__ __volatile__("movsw"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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return to;
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default: __asm__ __volatile__("movsw\n\tmovsb"
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:"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
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return to;
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}
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}
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#define __HAVE_ARCH_MEMCPY
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#ifdef CONFIG_X86_USE_3DNOW
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#include <asm/mmx.h>
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/*
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* This CPU favours 3DNow strongly (eg AMD Athlon)
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*/
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static inline void * __constant_memcpy3d(void * to, const void * from, size_t len)
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{
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if (len < 512)
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return __constant_memcpy(to, from, len);
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return _mmx_memcpy(to, from, len);
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}
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static __inline__ void *__memcpy3d(void *to, const void *from, size_t len)
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{
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if (len < 512)
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return __memcpy(to, from, len);
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return _mmx_memcpy(to, from, len);
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}
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#define memcpy(t, f, n) \
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(__builtin_constant_p(n) ? \
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__constant_memcpy3d((t),(f),(n)) : \
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__memcpy3d((t),(f),(n)))
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#else
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/*
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* No 3D Now!
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*/
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#define memcpy(t, f, n) \
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(__builtin_constant_p(n) ? \
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__constant_memcpy((t),(f),(n)) : \
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__memcpy((t),(f),(n)))
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#endif
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#define __HAVE_ARCH_MEMMOVE
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void *memmove(void * dest,const void * src, size_t n);
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#define memcmp __builtin_memcmp
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#define __HAVE_ARCH_MEMCHR
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extern void *memchr(const void * cs,int c,size_t count);
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static inline void * __memset_generic(void * s, char c,size_t count)
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{
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int d0, d1;
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__asm__ __volatile__(
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"rep\n\t"
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"stosb"
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: "=&c" (d0), "=&D" (d1)
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:"a" (c),"1" (s),"0" (count)
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:"memory");
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return s;
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}
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/* we might want to write optimized versions of these later */
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#define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))
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/*
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* memset(x,0,y) is a reasonably common thing to do, so we want to fill
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* things 32 bits at a time even when we don't know the size of the
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* area at compile-time..
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*/
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static __always_inline void * __constant_c_memset(void * s, unsigned long c, size_t count)
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{
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int d0, d1;
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__asm__ __volatile__(
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"rep ; stosl\n\t"
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"testb $2,%b3\n\t"
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"je 1f\n\t"
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"stosw\n"
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"1:\ttestb $1,%b3\n\t"
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"je 2f\n\t"
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"stosb\n"
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"2:"
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:"=&c" (d0), "=&D" (d1)
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:"a" (c), "q" (count), "0" (count/4), "1" ((long) s)
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:"memory");
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return (s);
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}
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/* Added by Gertjan van Wingerde to make minix and sysv module work */
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#define __HAVE_ARCH_STRNLEN
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extern size_t strnlen(const char * s, size_t count);
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/* end of additional stuff */
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#define __HAVE_ARCH_STRSTR
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extern char *strstr(const char *cs, const char *ct);
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/*
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* This looks horribly ugly, but the compiler can optimize it totally,
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* as we by now know that both pattern and count is constant..
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*/
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static __always_inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
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{
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switch (count) {
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case 0:
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return s;
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case 1:
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*(unsigned char *)s = pattern;
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return s;
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case 2:
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*(unsigned short *)s = pattern;
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return s;
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case 3:
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*(unsigned short *)s = pattern;
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*(2+(unsigned char *)s) = pattern;
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return s;
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case 4:
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*(unsigned long *)s = pattern;
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return s;
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}
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#define COMMON(x) \
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__asm__ __volatile__( \
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"rep ; stosl" \
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x \
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: "=&c" (d0), "=&D" (d1) \
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: "a" (pattern),"0" (count/4),"1" ((long) s) \
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: "memory")
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{
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int d0, d1;
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switch (count % 4) {
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case 0: COMMON(""); return s;
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case 1: COMMON("\n\tstosb"); return s;
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case 2: COMMON("\n\tstosw"); return s;
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default: COMMON("\n\tstosw\n\tstosb"); return s;
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}
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}
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#undef COMMON
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}
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#define __constant_c_x_memset(s, c, count) \
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(__builtin_constant_p(count) ? \
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__constant_c_and_count_memset((s),(c),(count)) : \
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__constant_c_memset((s),(c),(count)))
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#define __memset(s, c, count) \
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(__builtin_constant_p(count) ? \
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__constant_count_memset((s),(c),(count)) : \
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__memset_generic((s),(c),(count)))
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#define __HAVE_ARCH_MEMSET
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#define memset(s, c, count) \
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(__builtin_constant_p(c) ? \
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__constant_c_x_memset((s),(0x01010101UL*(unsigned char)(c)),(count)) : \
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__memset((s),(c),(count)))
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/*
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* find the first occurrence of byte 'c', or 1 past the area if none
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*/
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#define __HAVE_ARCH_MEMSCAN
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extern void *memscan(void * addr, int c, size_t size);
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#endif /* __KERNEL__ */
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#endif
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