Question

Code using assembly language

Create a program using the Irvine32 procedures were the user can input a list of 32-bit unsigned integers an “x” number of times, then display these integers to the console in reverse order.

Hint: Use loops and PUSH & POP instructions.

Extra Challenge: Inform the user with a message what to do; also, tell them what they are seeing.

Answer 1

Consider the following code fragment:

somenum = 0FFh ; define constant to FF hex

MOV ah, somenum ; move (i.e. copy) to the AH register

somenum = 0AAh ; re-define constant to AA hex

MOV ah, somenum ; move to the AH register

The above is equivalent to:

MOV ah, 0FFh

MOV ah, 0AAh

In the above, we redefined the value of the constant somenum. The following code would be invalid:

somenum = 0FFh

MOV somenum, ah ; INVALID

This would be akin to trying to do:

MOV 0FFh, ah ; Move accumulator high to FF? Not valid since FF is a number, not a storage loc

1 title Add and Subtract (AddSub.asm)

2 ; This program adds and subtracts 32-bit integers.

3

4 INCLUDE Irvine32.inc

5 .code

6 main PROC

7 mov eax, 10000h ; EAX = 10000h

8 add eax, 40000h ; EAX = 50000h

9 sub eax, 20000h ; EAX = 30000h

10 call DumpRegs ; Display registers

11 exit

12 main ENDP

13 END main

Alternate version of AddSub

By including irvine32.inc, we are hiding a number of details. Here is a description of some of these details shown in this alternate version of the same program:

1 title Alternate Add and Subtract (AddSubAlt.asm)

2 ; This program adds and subtracts 32-bit integers.

3

4 .386

5 .MODEL flat,stdcall

6 .STACK 4096

7 ExitProcess PROTO, dwExitCode: DWORD

8 DumpRegs PROTO

9 .code

10 main PROC

11 mov eax, 10000h ; EAX = 10000h

12 add eax, 40000h ; EAX = 50000h

13 sub eax, 20000h ; EAX = 30000h

14 call DumpRegs ; Display registers

15 INVOKE ExitProcess, 0

12 main ENDP

13 END main