问mov al，字节ptr [esi]和mov al，[num]的区别是什么？

EN

.386
.model flat, stdcall
.stack 1000h

Sleep proto arg1:dword
printf proto c arg1:ptr byte, printlist:vararg


.data
array db "hello" ,0
pointerByte dd offset array
fmtmsg1 db "%c",0

.code
public main

main proc

    mov esi,pointerByte
    mov cl,0
repeat_loop:

    push ecx

    mov al,byte ptr [esi]
    invoke printf,addr fmtmsg1,al

    inc esi

    pop ecx
    inc cl
    cmp cl,5
    jne repeat_loop

    ;done


   ret
main endp

end main