forked from 0ad/0ad
67 lines
1.2 KiB
C++
Executable File
67 lines
1.2 KiB
C++
Executable File
/*
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* block prefetch memcpy for large, uncached arrays
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*
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* src and len must be multiples of CHUNK_SIZE.
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*/
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#if _MSC_VER >= 0x1300
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void memcpy_nt(void* dst, void* src, int len)
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{
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__asm
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{
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push esi
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mov edx, [dst]
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mov esi, [src]
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mov ecx, [len]
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shr ecx, 12 ; # chunks
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; smaller than sub ecx, CHUNK_SIZE below
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main_loop:
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; prefetch: touch each cache line in chunk
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; (backwards to prevent hardware prefetches)
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; add esi, CHUNK_SIZE
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prefetch_loop:
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mov eax, [esi-64]
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mov eax, [esi-128]
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sub esi, 128
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test esi, 4095 ; CHUNK_SIZE-1 (icc doesn't preprocess asm)
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jnz prefetch_loop
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; copy the chunk 64 bytes at a time
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write_loop:
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movq mm0, [esi]
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movq mm1, [esi+8]
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movq mm2, [esi+16]
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movq mm3, [esi+24]
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movq mm4, [esi+32]
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movq mm5, [esi+40]
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movq mm6, [esi+48]
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movq mm7, [esi+56]
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add esi, 64
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test esi, 4095 ; CHUNK_SIZE-1
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movntq [edx], mm0
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movntq [edx+8], mm1
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movntq [edx+16], mm2
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movntq [edx+24], mm3
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movntq [edx+32], mm4
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movntq [edx+40], mm5
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movntq [edx+48], mm6
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movntq [edx+56], mm7
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lea edx, [edx+64] ; leave flags intact
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jnz write_loop
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dec ecx
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jnz main_loop
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sfence
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emms
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pop esi
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}
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}
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#endif // #if _MSC_VER >= 0x1300
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