diff options
Diffstat (limited to 'arch/x86/lib/memmove_64.c')
| -rw-r--r-- | arch/x86/lib/memmove_64.c | 189 |
1 files changed, 180 insertions, 9 deletions
diff --git a/arch/x86/lib/memmove_64.c b/arch/x86/lib/memmove_64.c index 0a33909..6d0f0ec 100644 --- a/arch/x86/lib/memmove_64.c +++ b/arch/x86/lib/memmove_64.c @@ -8,14 +8,185 @@ #undef memmove void *memmove(void *dest, const void *src, size_t count) { - if (dest < src) { - return memcpy(dest, src, count); - } else { - char *p = dest + count; - const char *s = src + count; - while (count--) - *--p = *--s; - } - return dest; + unsigned long d0,d1,d2,d3,d4,d5,d6,d7; + char *ret; + + __asm__ __volatile__( + /* Handle more 32bytes in loop */ + "mov %2, %3\n\t" + "cmp $0x20, %0\n\t" + "jb 1f\n\t" + + /* Decide forward/backward copy mode */ + "cmp %2, %1\n\t" + "jb 2f\n\t" + + /* + * movsq instruction have many startup latency + * so we handle small size by general register. + */ + "cmp $680, %0\n\t" + "jb 3f\n\t" + /* + * movsq instruction is only good for aligned case. + */ + "cmpb %%dil, %%sil\n\t" + "je 4f\n\t" + "3:\n\t" + "sub $0x20, %0\n\t" + /* + * We gobble 32byts forward in each loop. + */ + "5:\n\t" + "sub $0x20, %0\n\t" + "movq 0*8(%1), %4\n\t" + "movq 1*8(%1), %5\n\t" + "movq 2*8(%1), %6\n\t" + "movq 3*8(%1), %7\n\t" + "leaq 4*8(%1), %1\n\t" + + "movq %4, 0*8(%2)\n\t" + "movq %5, 1*8(%2)\n\t" + "movq %6, 2*8(%2)\n\t" + "movq %7, 3*8(%2)\n\t" + "leaq 4*8(%2), %2\n\t" + "jae 5b\n\t" + "addq $0x20, %0\n\t" + "jmp 1f\n\t" + /* + * Handle data forward by movsq. + */ + ".p2align 4\n\t" + "4:\n\t" + "movq %0, %8\n\t" + "movq -8(%1, %0), %4\n\t" + "lea -8(%2, %0), %5\n\t" + "shrq $3, %8\n\t" + "rep movsq\n\t" + "movq %4, (%5)\n\t" + "jmp 13f\n\t" + /* + * Handle data backward by movsq. + */ + ".p2align 4\n\t" + "7:\n\t" + "movq %0, %8\n\t" + "movq (%1), %4\n\t" + "movq %2, %5\n\t" + "leaq -8(%1, %0), %1\n\t" + "leaq -8(%2, %0), %2\n\t" + "shrq $3, %8\n\t" + "std\n\t" + "rep movsq\n\t" + "cld\n\t" + "movq %4, (%5)\n\t" + "jmp 13f\n\t" + + /* + * Start to prepare for backward copy. + */ + ".p2align 4\n\t" + "2:\n\t" + "cmp $680, %0\n\t" + "jb 6f \n\t" + "cmp %%dil, %%sil\n\t" + "je 7b \n\t" + "6:\n\t" + /* + * Calculate copy position to tail. + */ + "addq %0, %1\n\t" + "addq %0, %2\n\t" + "subq $0x20, %0\n\t" + /* + * We gobble 32byts backward in each loop. + */ + "8:\n\t" + "subq $0x20, %0\n\t" + "movq -1*8(%1), %4\n\t" + "movq -2*8(%1), %5\n\t" + "movq -3*8(%1), %6\n\t" + "movq -4*8(%1), %7\n\t" + "leaq -4*8(%1), %1\n\t" + + "movq %4, -1*8(%2)\n\t" + "movq %5, -2*8(%2)\n\t" + "movq %6, -3*8(%2)\n\t" + "movq %7, -4*8(%2)\n\t" + "leaq -4*8(%2), %2\n\t" + "jae 8b\n\t" + /* + * Calculate copy position to head. + */ + "addq $0x20, %0\n\t" + "subq %0, %1\n\t" + "subq %0, %2\n\t" + "1:\n\t" + "cmpq $16, %0\n\t" + "jb 9f\n\t" + /* + * Move data from 16 bytes to 31 bytes. + */ + "movq 0*8(%1), %4\n\t" + "movq 1*8(%1), %5\n\t" + "movq -2*8(%1, %0), %6\n\t" + "movq -1*8(%1, %0), %7\n\t" + "movq %4, 0*8(%2)\n\t" + "movq %5, 1*8(%2)\n\t" + "movq %6, -2*8(%2, %0)\n\t" + "movq %7, -1*8(%2, %0)\n\t" + "jmp 13f\n\t" + ".p2align 4\n\t" + "9:\n\t" + "cmpq $8, %0\n\t" + "jb 10f\n\t" + /* + * Move data from 8 bytes to 15 bytes. + */ + "movq 0*8(%1), %4\n\t" + "movq -1*8(%1, %0), %5\n\t" + "movq %4, 0*8(%2)\n\t" + "movq %5, -1*8(%2, %0)\n\t" + "jmp 13f\n\t" + "10:\n\t" + "cmpq $4, %0\n\t" + "jb 11f\n\t" + /* + * Move data from 4 bytes to 7 bytes. + */ + "movl (%1), %4d\n\t" + "movl -4(%1, %0), %5d\n\t" + "movl %4d, (%2)\n\t" + "movl %5d, -4(%2, %0)\n\t" + "jmp 13f\n\t" + "11:\n\t" + "cmp $2, %0\n\t" + "jb 12f\n\t" + /* + * Move data from 2 bytes to 3 bytes. + */ + "movw (%1), %4w\n\t" + "movw -2(%1, %0), %5w\n\t" + "movw %4w, (%2)\n\t" + "movw %5w, -2(%2, %0)\n\t" + "jmp 13f\n\t" + "12:\n\t" + "cmp $1, %0\n\t" + "jb 13f\n\t" + /* + * Move data for 1 byte. + */ + "movb (%1), %4b\n\t" + "movb %4b, (%2)\n\t" + "13:\n\t" + : "=&d" (d0), "=&S" (d1), "=&D" (d2), "=&a" (ret) , + "=r"(d3), "=r"(d4), "=r"(d5), "=r"(d6), "=&c" (d7) + :"0" (count), + "1" (src), + "2" (dest) + :"memory"); + + return ret; + } EXPORT_SYMBOL(memmove); |
