asm6502

A work-in-progress 6502 assembler.

This assembler currently serves the immediate needs of my NES emulator. As such, it doesn't do anything except translate literal 6502 assembly into machine code. Not even labels are supported, and relative addresses must specify a numeric offset. Any contributions are welcome, however. I'd love for this to become a more fully-featured assembler.

Usage

use asm6502::assemble;

let asm = "LDA #1\nADC #1\nCMP #2".as_bytes();
let mut buf = Vec::<u8>::new();
if let Err(msg) = assemble(asm, &mut buf) {
     panic!("Failed to assemble: {}", msg);
}
 
assert_eq!(&[0xa9, 0x1, 0x69, 0x1, 0xc9, 0x2], &buf[..]);

The the input and output parameters of the assemble function are generic over the Read and Write traits, respectively. A more typical usage of this function would accept an input file and an output file.

Known Issues

If the assembly ends with an implied instruction, it will need to be followed by a newline in order to be parsed correctly, and will fail to parse otherwise. See my StackOverflow question here documenting the issue and the work-in-progress nom pull request addressing the underlying issue.