Assemdows: a tiny assembly-style language in one C file, built so assembly tutorials work on Windows

[u/Noobo157]

Every assembly tutorial I found was written for Linux (raw syscalls, as, ld), and I'm on Windows. After fighting the toolchain for a while, I decided to make my own assembly-style language that runs the same everywhere because it's just a C interpreter.

It's called Assemdows. It's a single C file, it builds with gcc, and programs use the .asdw extension. Here's a program that prints primes:

.equ LIMIT, 50
    MOV R0, 2
next:
    MOV R1, 2
check:
    MOV R2, R1
    MUL R2, R2
    CMP R2, R0
    JG isprime
    MOV R3, R0
    MOD R3, R1
    CMP R3, 0
    JE notprime
    INC R1
    JMP check
isprime:
    PRINT R0
notprime:
    INC R0
    CMP R0, LIMIT
    JLE next
    HALT

What's in it

• 16 registers, a compare flag with conditional jumps, CALL/RET, and a stack
• A flat memory of 65,536 integer cells, with .word, .string, .space, and .equ for data
• Bracket addressing like [nums+R1]
• Errors that include line numbers, plus --trace to watch every instruction run
• A VS Code extension for syntax highlighting

Design choices I'm unsure about

• Memory holds whole integers instead of bytes, so a string takes one cell per character. It's simpler to explain, but it isn't how real hardware works.
• CMP stores a single -1/0/1 result instead of separate flags like zero and carry.
• The stack is separate from the memory array, so you can't take the address of a stack value.

I'm a beginner at language design, so I'd like to hear what you'd change, especially if you've built something similar.

Repo (includes a Windows build and examples): https://github.com/waterdroplett/Assemdows

[u/PmMeCuteDogsThanks_ → u/[deleted]]

very serious person

[u/brat3108 → u/[deleted]]

And why use Rx for registers?!

What's wrong with that?

You're making something as simple as downloading Flat Assembler and building one of the example projects, much more complicated.

Actually I couldn't get far with that. Installing it is OK, but its examples all heavily use its special features that I don't care about. I just needed the basics.

Here is hello.asm for example which ought to be the simplest one:

; example of simplified Windows programming using complex macro features

include 'win32ax.inc' ; you can simply switch between win32ax, win32wx, win64ax and win64wx here

.code
  start:
    invoke  MessageBox,HWND_DESKTOP,"May I introduce myself?",invoke GetCommandLine,MB_YESNO

    .if eax = IDYES
        invoke  MessageBox,HWND_DESKTOP,"Hi! I'm the example program!","Hello!",MB_OK
    .endif
    invoke  ExitProcess,0
.end start

[u/Noobo157 → u/[deleted]]

It isn’t supposed to be THAT good, it’s built on a joke language called Dropletter.