How to Add Values?

Question

New to Assembly language, reading a book here. I'm trying to do an simple basic exercise. Using appropriate registers, I have to add 100, 200, 300, 400, 500. Don't know where to start with this program. This is the outline of the program, now I need to add the registers. This is what I have, from what I understand from the book. Don't know how to keep adding.

(AddSub.asm)
INCLUDE Irvine32.inc

.code   

main PROC

    mov eax, 100
    add eax, 200

exit
main ENDP
END main

Accepted Answer

If you have experience with higher level languages like C, then these lines:

mov eax, 100
add eax, 200

Would do something akin to:

int eax;
eax = 100;       /* mov 100 to EAX */
eax = eax + 200; /* add 200 to EAX */

If you want to add other numbers you keep adding to EAX like:

add eax, 300
add eax, 400

You can use other registers besides EAX (like EBX,ECX,EDX,ESI,EDI). You can also add these registers together. For example

mov eax, 100
mov ebx, 200
mov ecx, 300
add eax, ebx
add eax, ecx

This would be akin to:

int eax = 100;
int ebx = 200;
int ecx = 300;

eax = eax + ebx; /* add EBX to EAX */
eax = eax + ecx; /* add ECX to EAX */

Which would result in a value of 600 in EAX

Using Irvine32 library you can print the contents of EAX as a signed integer by calling the WriteInt function like so:

call WriteInt

Answer 2

Just add more add instructions:

add eax, 300
add eax, 400
add eax, 500

You also have to print out the result somehow, before your exit line.

Answer 3

I think you should keep adding add the numbers to the eax register right after the mov instruction. From the little i know this is what the eax is for.

section .text


global __start
__start:
mov eax, 100
add  eax, 200
add eax, 300
add eax, 400
add eax, 500

; you can print it out here

mov eax, 1
Int 0x80

I hope this helps.

How to Add Values?

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How to Add Values?

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