zerodmg-codes 0.1.9

pieces of a naive incomplete broken game boy emulator
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use crate::assembled::prelude::*;
use crate::disassembled::prelude::*;

const DMG_BOOT: &[u8; 0x0100] = &[
    0x31, 0xFE, 0xFF, 0xAF, 0x21, 0xFF, 0x9F, 0x32, 0xCB, 0x7C, 0x20, 0xFB, 0x21, 0x26, 0xFF, 0x0E,
    0x11, 0x3E, 0x80, 0x32, 0xE2, 0x0C, 0x3E, 0xF3, 0xE2, 0x32, 0x3E, 0x77, 0x77, 0x3E, 0xFC, 0xE0,
    0x47, 0x11, 0x04, 0x01, 0x21, 0x10, 0x80, 0x1A, 0xCD, 0x95, 0x00, 0xCD, 0x96, 0x00, 0x13, 0x7B,
    0xFE, 0x34, 0x20, 0xF3, 0x11, 0xD8, 0x00, 0x06, 0x08, 0x1A, 0x13, 0x22, 0x23, 0x05, 0x20, 0xF9,
    0x3E, 0x19, 0xEA, 0x10, 0x99, 0x21, 0x2F, 0x99, 0x0E, 0x0C, 0x3D, 0x28, 0x08, 0x32, 0x0D, 0x20,
    0xF9, 0x2E, 0x0F, 0x18, 0xF3, 0x67, 0x3E, 0x64, 0x57, 0xE0, 0x42, 0x3E, 0x91, 0xE0, 0x40, 0x04,
    0x1E, 0x02, 0x0E, 0x0C, 0xF0, 0x44, 0xFE, 0x90, 0x20, 0xFA, 0x0D, 0x20, 0xF7, 0x1D, 0x20, 0xF2,
    0x0E, 0x13, 0x24, 0x7C, 0x1E, 0x83, 0xFE, 0x62, 0x28, 0x06, 0x1E, 0xC1, 0xFE, 0x64, 0x20, 0x06,
    0x7B, 0xE2, 0x0C, 0x3E, 0x87, 0xE2, 0xF0, 0x42, 0x90, 0xE0, 0x42, 0x15, 0x20, 0xD2, 0x05, 0x20,
    0x4F, 0x16, 0x20, 0x18, 0xCB, 0x4F, 0x06, 0x04, 0xC5, 0xCB, 0x11, 0x17, 0xC1, 0xCB, 0x11, 0x17,
    0x05, 0x20, 0xF5, 0x22, 0x23, 0x22, 0x23, 0xC9, 0xCE, 0xED, 0x66, 0x66, 0xCC, 0x0D, 0x00, 0x0B,
    0x03, 0x73, 0x00, 0x83, 0x00, 0x0C, 0x00, 0x0D, 0x00, 0x08, 0x11, 0x1F, 0x88, 0x89, 0x00, 0x0E,
    0xDC, 0xCC, 0x6E, 0xE6, 0xDD, 0xDD, 0xD9, 0x99, 0xBB, 0xBB, 0x67, 0x63, 0x6E, 0x0E, 0xEC, 0xCC,
    0xDD, 0xDC, 0x99, 0x9F, 0xBB, 0xB9, 0x33, 0x3E, 0x3C, 0x42, 0xB9, 0xA5, 0xB9, 0xA5, 0x42, 0x3C,
    0x21, 0x04, 0x01, 0x11, 0xA8, 0x00, 0x1A, 0x13, 0xBE, 0x20, 0xFE, 0x23, 0x7D, 0xFE, 0x34, 0x20,
    0xF5, 0x06, 0x19, 0x78, 0x86, 0x23, 0x05, 0x20, 0xFB, 0x86, 0x20, 0xFE, 0x3E, 0x01, 0xE0, 0x50,
];

/// The initial boot ROM for the original Game Boy.
pub fn dmg_boot() -> DisassembledRom {
    let rom = DisassembledRom::from(vec![block(0x0000, DMG_BOOT.to_vec())]);
    if cfg!(debug_assertions) {
        verify(&rom);
    }
    rom
}

/// A sanity-check/test of the result, only checked in debug mode and tests.
fn verify(rom: &DisassembledRom) {
    let known_vec = DMG_BOOT.to_vec();

    println!("=== Boot ROM ===");
    println!("{:?}\n", rom);
    println!("{}\n", rom);

    println!("=== Assembled Boot ROM ===");
    let assembled_bytes = rom.assemble().to_bytes();
    println!("{:?}\n", assembled_bytes);
    assert_eq!(known_vec, assembled_bytes);

    println!("=== Disassembled Boot ROM ===");
    let mut assembled = AssembledRom::from_bytes(&assembled_bytes);
    // TODO: actually be able to safely trace this without exploding
    // assembled.get_known_instruction(0x0000);
    let disassembled = assembled.disassemble();
    println!("{:?}\n", disassembled);
    println!("{}\n", disassembled);

    let reassembled_bytes = disassembled.assemble().to_bytes();
    assert_eq!(known_vec, reassembled_bytes);
}

#[test]
fn test_verified() {
    dmg_boot();
}