[問題] VC的內聯匯編，不能用64位寄存器?
自己寫了個memcpy 函數，練習下匯編:
#define DIV4(AA) ((AA) >> 2)
#define ASM __asm
void asm_memcpy(void *pDst, void *pSrc, size_t size)
{
unsigned int i;
unsigned int nLoops;
nLoops = DIV4(size);
char *pMovDst, *pMovSrc;
pMovDst = (char*)pDst;
pMovSrc = (char*)pSrc;
for(i = 0; i < nLoops; i++){
ASM
{
mov esi, pSrc;
mov edi, pDst;
mov ebx , i;
mov ecx, [esi + ebx*4];
mov [edi + ebx*4], ecx;
}/*ASM*/
}/*for i nLoops*/
for(i = nLoops*4; i< size; i++)
pMovDst[i] = pMovSrc[i];
}/*asm_memcpy*/
(這效能比標準的 memcpy 稍稍快一點點，或打平手)
這目前這是用ecx ( 32位) 來做中間的寄存氣，所以一次只能複製4字節
想用 rcx (64位) 以達更大的效能
不過 vc會擋哩:
error C2415: improper operand type
那請問 vc 中不可使用到 64位寄存器嗎?
謝謝
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◆ From: 59.120.158.204
※ 編輯: DrStein 來自: 59.120.158.204 (06/10 13:58)
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