Simple ARMv8 Interpreter/Simulator

This used to be a live website but I took it down since I don't think I'll be coming back to this project. RIP mylittlearmsim

A class on machine organization I took last semester used an armv8 simulator to grade our code for quizzes and I thought it was cool so I decided to give it a shot. It's not the most efficient or robust system but it's been a fun way to try my hand at writing an "interpreter."

I made this using flask and python 3.8.6, reg.py holds all the ARM-esque logic and features like registers, labels, etc. views.py has one view in it, sim, which gets code from the textarea in templates/home.html and uses the parsing function from reg.py to parse the code and call the right functions from reg.py

The site is hosted on a Linode server running Ubuntu 20.04 LTS and I'm using Nginx and uWSGI to actually get HTTP requests to the app. Basic tutorial on setting that up here

NOTE: The stack is a bit buggy as of right now, use sub to grow it, shrink it by adding the same number you subbed by (example below) and make sure those are all multiples of 4

NOTE: The local testing folder contains a version of this app that runs in a terminal but will soon be used to contain unit tests for the functions

Features, current and future:

Completed features:

• arithmetic (add, sub, mul, no div)
• mov
• labels, cmp, and branching (cbz, cbnz, bl, b, b.gt, b.lt, b.eq, b.ge, b.le)
• grow, shrink, str, and ldr the stack pointer (str/ldr don't work with other registers, just sp)
• comments (single-line, denoted by "@") get removed and don't mess up code execution

Future features (hopefully):

• str/ldr for registers other than sp
• svc, more robust stack, and heap limits
• adds, subs, and (bitwise) instructions
• printing and handling strings
• animated visual for stack changes
• recursion

Sample Programs:

These will show most of the features that are completed thus far. Just copy and paste them into the textarea and click assemble.

1. finds the x0th fibonacci number (edit line 2 to change which one) iteratively

main:
      mov x0, 10
      mov x1, #1
      mov x2, #1
      mov x3, #0
      START:
            cmp x0, x1
            b.gt LOOP
            b.eq END
      LOOP:
            add x4, x2, x3
            mov x3, x2
            mov x2, x4
            add x1, x1, #1
            b START
      END:
            mov x0, x4

2. example of how to use bl and branch with lr (conditions not supported)

mov x1, 2
.here:
    mov x0, x1
    bl .there
    add x1, x1, 10
    b .end
.there:
    mov x1, 5
    b lr
.end:

3. example of using the stack to str/ldr values

sub sp, sp, 16
mov x1, 1
str x1, [sp, 8]
ldr x0, [sp, 8]
add sp, sp, 16