result of subtracting numbers from 32 to 64

Question

result of subtracting numbers from 32 to 64

I am learning to program in assembly and I have a problem which is the following:

I have a result of a 32-bit number subtraction, and it has to return a 64-bit number.

Note: I'm using a 32-bit linux VM

0

assembly

Author: Max Tag, 2017-10-19

Source

1 answers

score 0 · Answer 1

.intel_syntax noprefix

.comm   diff64, 8, 8         # Declara simbolo de 64 bits

MOV EBX, 87654321            # Minuendo em EBX
MOV EAX, 12345678            # Subtraendo em EAX

SUB EBX, EAX                 # Subtrai EAX de EBX, resultado em EAX

MOV DWORD PTR diff64, EAX    # Preenche 32bits menos significativos do simbolo de 64bits
MOV DWORD PTR diff64 + 4, 0  # Preenche 32bits mais significativos do simbolo de 64bits