.intel_syntax noprefix

.text

.global amemmove

amemmove:
    push    ebp
    push    esi
    push    edi
    mov ebp,esp
    mov edi, DWORD PTR [ebp+8]      # edi = *dest
    mov esi, DWORD PTR [ebp+12]     # esi = *src
    mov ecx, WORD [ebp+16]      # ecx = nbytes
    mov eax, esi
    sub eax, ecx            # eax = src - nbytes
    cmp edi, eax
    jl  rightcpy
    mov edx, esi
    add edx, ecx            # edx = src + btytes
    cmp eax, edx
    jg  rightcpy
    jmp leftcpy

leftcpy:
    std

rightcpy:
rep movsb
    cld
    mov esp, ebp
    pop edi
    pop esi
    pop ebp
    ret

.end