vas - An x86-64 Assembler Written in V

vas is a lightweight assembler written in the V programming language that supports Linux x86-64 assembly with AT&T syntax. It compiles assembly source files into object files that can be linked with ld.

Features

• x86-64 instruction set support
• AT&T syntax
• ELF object file generation
• Support for common assembler directives
• Standard input support via - argument

Installation

Docker setup

# Build the Docker image
docker build ./ -t vas

# Run the container
# Linux/MacOS:
docker run --rm -it -v "$(pwd)":/root/env vas

# Windows (CMD):
docker run --rm -it -v "%cd%":/root/env vas

# Windows (PowerShell):
docker run --rm -it -v "${pwd}:/root/env" vas

Build

Requires the V compiler to be installed.

v . -prod

Usage

Basic usage:

vas [options] <input_file>.s

Options:

• -o <filename>: Set output file name (default: input_file.o)
• --keep-locals: Keep local symbols (e.g., those starting with .L)

Example

1. Create an assembly file (hello.s):

# Hello world example

.global _start

.section .data, "aw"
msg:
  .string "Hello, world!\n"

.section .text, "ax"
_start:
  pushq %rbp
  movq %rsp, %rbp
  subq $16, %rsp

  movq $1, %rax    # write syscall
  movq $1, %rdi    # stdout
  movq $msg, %rsi  # message
  movq $14, %rdx   # length
  syscall

  movq $60, %rax   # exit syscall
  movq $0, %rdi    # status code 0
  syscall

2. Assemble the file:

vas hello.s

3. Link the object file:

ld hello.o

4. Run the executable:

./a.out

Output:

Hello, world!

Posts on X

• https://x.com/v_language/status/1643642842214957061

• https://x.com/ibuki42O/status/1607026393518604290

• https://x.com/ibuki42O/status/1670080123369058304

License

This project is licensed under the MIT License - see the LICENSE file for details.