.386
.model flat, stdcall

option casemap: none

.data
    x db 11010101b

.code
start:
    mov eax, 0
    mov ebx, 0

    mov al, x
    mov bl, 28
    and al, bl

    not al

    mov bl, 4
    imul bl

    xor al, 00111000b

    ret
    end start