Question

Write the lines to add a number in alto a number in bl and save the result in ax register. note that the results

A) MOV AX, AL
ADD AX, BL

B) MOV AX, AL
ADD BL, AX

C) MOV AX, AL
ADD AX, BX

D) MOV AX, BX
ADD AX, BL

Answer 1

In x86 assembly, the correct code to move a value from AL to AX and then add the value from BL is 'MOV AX, AL' followed by 'ADD AX, BL'. These instructions first zero-extend the AL value to AX and then add the value of BL to AX.

Step-by-step explanation:

The student is working with assembly language programming, specifically with x86 instruction set. The goal is to move the value from register AL to AX and then add the value from register BL to it.

The correct lines of assembly code to achieve this would be:

• MOV AX, AL
• ADD AX, BL

This sequence first moves the value from the AL register to the AX register, effectively zero-extending it to fill the AX register if AL is smaller. Next, it adds the value in the BL register to the AX register, storing the result back in AX. Note that AL is the lower byte of AX, and BL is the lower byte of BX; these are 8-bit registers part of the larger 16-bit registers AX and BX respectively.