Write an assembly program that:

Question

- Multiply the content of AL by 5. Use a loop to implement the multiplication (Do not use MUL or IMUL).

Answer 1

Assuming that we only need to multiply 8-bit numbers (since we are using AL), we can implement a simple loop that adds the value of AL to itself 4 times (which is equivalent to multiplying by 5). Here is an example implementation:

start:
mov bl, 4 ; set loop counter to 4 (since we need to add AL to itself 4 times)
mov ah, 0 ; clear AH register
loop_start:
add al, al ; add AL to itself
dec bl ; decrement loop counter
jnz loop_start ; jump to loop_start if counter is not zero
; multiplication is done, result is in AL
; add your code here to use the result

Explanation:
We start by loading the loop counter (4) into BL and clearing the AH register. Then we start our loop by adding the value of AL to itself using the ADD instruction. We then decrement the loop counter using the DEC instruction and check if it is zero using the JNZ instruction. If the counter is not zero, we jump back to the start of the loop and repeat the process. Once the loop has completed, the result (which is AL multiplied by 5) is ready to be used.

Note that this is a very basic implementation and there are many other ways to implement multiplication in assembly language. This is just one example that demonstrates the use of loops for multiplication.