Function patch_la

crates/asm-to-binary/src/object_linker.rs:481–501

(
    section_bytes: &mut [u8],
    site: usize,
    site_abs: u64,
    target_abs: u64,
    addend: i64,
)

    let (hi20, lo12) = crate::isa::pcrel_split(offset);

    let auipc_patched = (auipc_word & 0x0000_0FFF) | (((hi20 << 12) as u32) & 0xFFFF_F000);
    let jalr_patched = (jalr_word & !(0xFFF << 20)) | (((lo12 as u32) & 0xFFF) << 20);

    write_u32_at(section_bytes, site, auipc_patched)?;
    write_u32_at(section_bytes, site + 4, jalr_patched)?;
    Ok(())
}

fn patch_jal(
    section_bytes: &mut [u8],
    site: usize,
    site_abs: u64,
    target_abs: u64,
    addend: i64,
) -> Result<(), LinkerError> {
    let jal_word = read_u32_at(section_bytes, site)?;
    let offset = (target_abs as i64)
        .wrapping_add(addend)
        .wrapping_sub(site_abs as i64);

    if (offset & 1) != 0 {
        return Err(LinkerError::new(format!(
            "JAL relocation offset {offset} is not 2-byte aligned"
        )));