disassembling melee with radare2 from rust

disasm.rs

use r2pipe::{R2Pipe, R2PipeSpawnOptions};

/// Filename of GALE01 v1.02 GCM disk image.
const SSBM_ISO: &str = "ssbm.iso";

/// Filename of converted main.dol -> main.elf, converted with doltool.
const MAIN_DOL: &str = "main.elf";

/// Offset of get_rand_int in main.elf and in memory.
///
/// Taken from SSBM datasheet.
const MEMORY_GET_RAND_INT_OFFSET: u64 = 0x80380580;

/// Taken from melee community symbol map.
const MEMORY_PEACH_DOWNB_GEN_TURNIP: u64 = 0x8011d018;

struct MeleeAnalyzer {
    r2p: R2Pipe,
}

impl MeleeAnalyzer {
    fn new<S: AsRef<str>>(filename: S) -> Result<Self, String> {
        let mut r2p = R2Pipe::spawn(
            MAIN_DOL,
            Some(R2PipeSpawnOptions {
                exepath: "r2".to_string(),
                args: vec!["-a", "ppc"],
            }),
        )
        .expect("failed to spawn r2");
        eprintln!("spawned r2, running analysis...");
        r2p.cmd("aaa").or(Err("failed analysis"))?;
        Ok(MeleeAnalyzer { r2p })
    }

    fn disasm_function(&mut self, offset: u64) -> Result<String, String> {
        self.r2p
            .cmd(format!("s {}", offset).as_str())
            .or(Err("failed to seek to subroutine"))?;
        let disasm = self
            .r2p
            .cmd("pdf")
            .or(Err("failed to disassemble subroutine"))?;
        Ok(disasm)
    }
    fn disasm_instructions(&mut self, offset: u64, instructions: u64) -> Result<String, String> {
        self.r2p
            .cmd(format!("s {}", offset).as_str())
            .or(Err("failed to seek to subroutine"))?;
        let disasm = self
            .r2p
            .cmd(format!("pd {}", instructions).as_str())
            .or(Err("failed to disassemble subroutine"))?;
        Ok(disasm)
    }
}

fn main() -> Result<(), String> {
    let mut analyzer = MeleeAnalyzer::new(MAIN_DOL)?;
    {
        let disasm = analyzer.disasm_function(MEMORY_GET_RAND_INT_OFFSET)?;
        println!("get_rand_int:\n{disasm}");
    }
    {
        let disasm = analyzer.disasm_instructions(0x8011d088, 3)?;
        println!("peach_turnip_rng:\n{disasm}");
    }
    Ok(())
}

output.txt

get_rand_int:
            ; XREFS(736)
┌ 60: fcn.80380580 ();
│           0x80380580      80ada8f4       lwz r5, -0x570c(r13)
│           0x80380584      3c800003       lis r4, 3
│           0x80380588      380443fd       addi r0, r4, 0x43fd
│           0x8038058c      80850000       lwz r4, 0(r5)
│           0x80380590      7c8401d6       mullw r4, r4, r0
│           0x80380594      3c840027       addis r4, r4, 0x27
│           0x80380598      38049ec3       addi r0, r4, 0x9ec3
│           0x8038059c      90050000       stw r0, 0(r5)
│           0x803805a0      808da8f4       lwz r4, -0x570c(r13)
│           0x803805a4      80040000       lwz r0, 0(r4)
│           0x803805a8      5400843e       srwi r0, r0, 0x10
│           0x803805ac      7c0301d6       mullw r0, r3, r0
│           0x803805b0      7c038670       srawi r3, r0, 0x10
│           0x803805b4      7c630194       addze r3, r3
└           0x803805b8      4e800020       blr

peach_turnip_rng:
            0x8011d088      482634f9       bl fcn.80380580
            0x8011d08c      2c030000       cmpwi r3, 0
        ┌─< 0x8011d090      40820010       bne 0x8011d0a0