9.4: Stack Example

Last updated
Save as PDF

Page ID: 19914

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

The following is an example program to use the stack to reverse a list of quadwords in place. Specifically, each value in a quadword array is placed on the stack in the first loop. In the second loop, each element is removed from the stack and placed back into the array (over-writing) the previous value.

; Simple example demonstrating basic stack operations.

; Reverse a list of numbers - in place.
; Method: Put each number on stack, then pop each number
;         back off, and then put back into memory.

; *****************************************************
;  Data declarations

section .data

; -----
;  Define constants

EXIT_SUCCESS     equ     0             ; successful operation
SYS_exit         equ     60            ; call code for terminate

; -----
;  Define Data.

numbers         dq        121, 122, 123, 124, 125 
len             dq        5 

; **************************************************** section .text
global _start
_start: 

;  Loop to put numbers on stack.

    mov     rcx, qword [len] 
    mov     rbx, numbers
    mov     r12, 0
    mov     rax, 0

pushLoop:
    push    qword [rbx+r12*8]
    inc     r12 
    loop    pushLoop

; -----
;  All the numbers are on stack (in reverse order).
;  Loop to get them back off.
;  the original list...

    mov     rcx, qword [len] 
    mov     rbx, numbers 
    mov     r12, 0

popLoop:
    pop     rax
    mov     qword [rbx+r12*8], rax 
    inc     r12
    loop    popLoop

; -----
;  Done, terminate program.

last:
    mov     rax, SYS_exit                 ; call code for exit
    mov     rdi, EXIT_SUCCESS             ; exit with success
    syscall

There are other ways to accomplish this function (reversing a list), however this is meant to demonstrate the stack operations.