forked from Minki/linux
3b4b682bec
movs instruction will combine data to accelerate moving data, however we need to concern two cases about it. 1. movs instruction need long lantency to startup, so here we use general mov instruction to copy data. 2. movs instruction is not good for unaligned case, even if src offset is 0x10, dest offset is 0x0, we avoid and handle the case by general mov instruction. Signed-off-by: Ma Ling <ling.ma@intel.com> LKML-Reference: <1284664360-6138-1-git-send-email-ling.ma@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
209 lines
3.7 KiB
C
209 lines
3.7 KiB
C
#include <linux/string.h>
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#include <linux/module.h>
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#undef memcpy
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#undef memset
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void *memcpy(void *to, const void *from, size_t n)
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{
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#ifdef CONFIG_X86_USE_3DNOW
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return __memcpy3d(to, from, n);
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#else
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return __memcpy(to, from, n);
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#endif
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}
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EXPORT_SYMBOL(memcpy);
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void *memset(void *s, int c, size_t count)
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{
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return __memset(s, c, count);
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}
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EXPORT_SYMBOL(memset);
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void *memmove(void *dest, const void *src, size_t n)
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{
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int d0,d1,d2,d3,d4,d5;
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char *ret = dest;
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__asm__ __volatile__(
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/* Handle more 16bytes in loop */
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"cmp $0x10, %0\n\t"
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"jb 1f\n\t"
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/* Decide forward/backward copy mode */
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"cmp %2, %1\n\t"
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"jb 2f\n\t"
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/*
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* movs instruction have many startup latency
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* so we handle small size by general register.
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*/
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"cmp $680, %0\n\t"
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"jb 3f\n\t"
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/*
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* movs instruction is only good for aligned case.
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*/
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"mov %1, %3\n\t"
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"xor %2, %3\n\t"
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"and $0xff, %3\n\t"
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"jz 4f\n\t"
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"3:\n\t"
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"sub $0x10, %0\n\t"
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/*
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* We gobble 16byts forward in each loop.
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*/
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"3:\n\t"
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"sub $0x10, %0\n\t"
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"mov 0*4(%1), %3\n\t"
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"mov 1*4(%1), %4\n\t"
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"mov %3, 0*4(%2)\n\t"
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"mov %4, 1*4(%2)\n\t"
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"mov 2*4(%1), %3\n\t"
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"mov 3*4(%1), %4\n\t"
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"mov %3, 2*4(%2)\n\t"
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"mov %4, 3*4(%2)\n\t"
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"lea 0x10(%1), %1\n\t"
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"lea 0x10(%2), %2\n\t"
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"jae 3b\n\t"
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"add $0x10, %0\n\t"
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"jmp 1f\n\t"
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/*
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* Handle data forward by movs.
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*/
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".p2align 4\n\t"
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"4:\n\t"
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"mov -4(%1, %0), %3\n\t"
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"lea -4(%2, %0), %4\n\t"
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"shr $2, %0\n\t"
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"rep movsl\n\t"
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"mov %3, (%4)\n\t"
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"jmp 11f\n\t"
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/*
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* Handle data backward by movs.
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*/
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".p2align 4\n\t"
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"6:\n\t"
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"mov (%1), %3\n\t"
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"mov %2, %4\n\t"
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"lea -4(%1, %0), %1\n\t"
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"lea -4(%2, %0), %2\n\t"
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"shr $2, %0\n\t"
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"std\n\t"
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"rep movsl\n\t"
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"mov %3,(%4)\n\t"
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"cld\n\t"
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"jmp 11f\n\t"
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/*
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* Start to prepare for backward copy.
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*/
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".p2align 4\n\t"
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"2:\n\t"
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"cmp $680, %0\n\t"
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"jb 5f\n\t"
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"mov %1, %3\n\t"
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"xor %2, %3\n\t"
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"and $0xff, %3\n\t"
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"jz 6b\n\t"
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/*
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* Calculate copy position to tail.
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*/
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"5:\n\t"
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"add %0, %1\n\t"
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"add %0, %2\n\t"
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"sub $0x10, %0\n\t"
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/*
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* We gobble 16byts backward in each loop.
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*/
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"7:\n\t"
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"sub $0x10, %0\n\t"
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"mov -1*4(%1), %3\n\t"
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"mov -2*4(%1), %4\n\t"
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"mov %3, -1*4(%2)\n\t"
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"mov %4, -2*4(%2)\n\t"
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"mov -3*4(%1), %3\n\t"
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"mov -4*4(%1), %4\n\t"
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"mov %3, -3*4(%2)\n\t"
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"mov %4, -4*4(%2)\n\t"
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"lea -0x10(%1), %1\n\t"
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"lea -0x10(%2), %2\n\t"
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"jae 7b\n\t"
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/*
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* Calculate copy position to head.
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*/
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"add $0x10, %0\n\t"
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"sub %0, %1\n\t"
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"sub %0, %2\n\t"
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/*
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* Move data from 8 bytes to 15 bytes.
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*/
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".p2align 4\n\t"
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"1:\n\t"
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"cmp $8, %0\n\t"
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"jb 8f\n\t"
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"mov 0*4(%1), %3\n\t"
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"mov 1*4(%1), %4\n\t"
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"mov -2*4(%1, %0), %5\n\t"
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"mov -1*4(%1, %0), %1\n\t"
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"mov %3, 0*4(%2)\n\t"
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"mov %4, 1*4(%2)\n\t"
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"mov %5, -2*4(%2, %0)\n\t"
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"mov %1, -1*4(%2, %0)\n\t"
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"jmp 11f\n\t"
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/*
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* Move data from 4 bytes to 7 bytes.
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*/
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".p2align 4\n\t"
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"8:\n\t"
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"cmp $4, %0\n\t"
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"jb 9f\n\t"
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"mov 0*4(%1), %3\n\t"
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"mov -1*4(%1, %0), %4\n\t"
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"mov %3, 0*4(%2)\n\t"
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"mov %4, -1*4(%2, %0)\n\t"
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"jmp 11f\n\t"
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/*
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* Move data from 2 bytes to 3 bytes.
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*/
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".p2align 4\n\t"
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"9:\n\t"
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"cmp $2, %0\n\t"
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"jb 10f\n\t"
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"movw 0*2(%1), %%dx\n\t"
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"movw -1*2(%1, %0), %%bx\n\t"
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"movw %%dx, 0*2(%2)\n\t"
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"movw %%bx, -1*2(%2, %0)\n\t"
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"jmp 11f\n\t"
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/*
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* Move data for 1 byte.
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*/
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".p2align 4\n\t"
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"10:\n\t"
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"cmp $1, %0\n\t"
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"jb 11f\n\t"
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"movb (%1), %%cl\n\t"
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"movb %%cl, (%2)\n\t"
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".p2align 4\n\t"
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"11:"
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: "=&c" (d0), "=&S" (d1), "=&D" (d2),
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"=r" (d3),"=r" (d4), "=r"(d5)
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:"0" (n),
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"1" (src),
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"2" (dest)
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:"memory");
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return ret;
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}
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EXPORT_SYMBOL(memmove);
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