汇编-memcpy的实现

memcpystack proc dest,src,cnt

;cnt is a count of dwords

    ;this function has a granularity of dwords

    mov edx,src

    mov eax,dest

    sub eax,edx

    sub eax,4

    mov ecx,cnt

    xchg esp,edx

    .repeat

        pop dword ptr[esp+eax]

        dec ecx

    .until zero?

    xchg esp,edx

    ret
memcpystack endp
memcpy1 proc dest,src,cnt
mov edx,src

    mov ebx,dest

    mov ecx,cnt

    .repeat

        mov eax,dword ptr[edx]

        mov dword ptr[ebx],eax

        add edx,4

        add eax,4

        dec ecx

    .until zero?

    ret
memcpy1 endp
memcpy2 proc dest,src,cnt
mov edx,src

    mov ebx,dest

    mov ecx,cnt

    .repeat

        push dword ptr[edx]

        pop dword ptr[ebx]

        add edx,4

        add ebx,4

        dec ecx

    .until zero?

    ret
memcpy2 endp
memcpy3 proc dest,src,cnt
mov esi,src

    mov edi,dest

    mov ecx,cnt

    rep movsd

    ret
memcpy3 endp

汇编-memcpy的实现