diff options
| -rw-r--r-- | include/asm-i386/string.h | 89 |
1 files changed, 61 insertions, 28 deletions
diff --git a/include/asm-i386/string.h b/include/asm-i386/string.h index 1679983d053f..6a78ac58c194 100644 --- a/include/asm-i386/string.h +++ b/include/asm-i386/string.h @@ -198,47 +198,80 @@ static inline void * __memcpy(void * to, const void * from, size_t n) int d0, d1, d2; __asm__ __volatile__( "rep ; movsl\n\t" - "testb $2,%b4\n\t" - "je 1f\n\t" - "movsw\n" - "1:\ttestb $1,%b4\n\t" - "je 2f\n\t" - "movsb\n" - "2:" + "movl %4,%%ecx\n\t" + "andl $3,%%ecx\n\t" +#if 1 /* want to pay 2 byte penalty for a chance to skip microcoded rep? */ + "jz 1f\n\t" +#endif + "rep ; movsb\n\t" + "1:" : "=&c" (d0), "=&D" (d1), "=&S" (d2) - :"0" (n/4), "q" (n),"1" ((long) to),"2" ((long) from) + : "0" (n/4), "g" (n), "1" ((long) to), "2" ((long) from) : "memory"); return (to); } /* - * This looks horribly ugly, but the compiler can optimize it totally, + * This looks ugly, but the compiler can optimize it totally, * as the count is constant. */ static inline void * __constant_memcpy(void * to, const void * from, size_t n) { - if (n <= 128) - return __builtin_memcpy(to, from, n); - -#define COMMON(x) \ -__asm__ __volatile__( \ - "rep ; movsl" \ - x \ - : "=&c" (d0), "=&D" (d1), "=&S" (d2) \ - : "0" (n/4),"1" ((long) to),"2" ((long) from) \ - : "memory"); -{ - int d0, d1, d2; + long esi, edi; + if (!n) return to; +#if 1 /* want to do small copies with non-string ops? */ + switch (n) { + case 1: *(char*)to = *(char*)from; return to; + case 2: *(short*)to = *(short*)from; return to; + case 4: *(int*)to = *(int*)from; return to; +#if 1 /* including those doable with two moves? */ + case 3: *(short*)to = *(short*)from; + *((char*)to+2) = *((char*)from+2); return to; + case 5: *(int*)to = *(int*)from; + *((char*)to+4) = *((char*)from+4); return to; + case 6: *(int*)to = *(int*)from; + *((short*)to+2) = *((short*)from+2); return to; + case 8: *(int*)to = *(int*)from; + *((int*)to+1) = *((int*)from+1); return to; +#endif + } +#endif + esi = (long) from; + edi = (long) to; + if (n >= 5*4) { + /* large block: use rep prefix */ + int ecx; + __asm__ __volatile__( + "rep ; movsl" + : "=&c" (ecx), "=&D" (edi), "=&S" (esi) + : "0" (n/4), "1" (edi),"2" (esi) + : "memory" + ); + } else { + /* small block: don't clobber ecx + smaller code */ + if (n >= 4*4) __asm__ __volatile__("movsl" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + if (n >= 3*4) __asm__ __volatile__("movsl" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + if (n >= 2*4) __asm__ __volatile__("movsl" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + if (n >= 1*4) __asm__ __volatile__("movsl" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + } switch (n % 4) { - case 0: COMMON(""); return to; - case 1: COMMON("\n\tmovsb"); return to; - case 2: COMMON("\n\tmovsw"); return to; - default: COMMON("\n\tmovsw\n\tmovsb"); return to; + /* tail */ + case 0: return to; + case 1: __asm__ __volatile__("movsb" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + return to; + case 2: __asm__ __volatile__("movsw" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + return to; + default: __asm__ __volatile__("movsw\n\tmovsb" + :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory"); + return to; } } - -#undef COMMON -} #define __HAVE_ARCH_MEMCPY |
