main.rs

    // find the segmented address of STAGE3_ENTRY
    // be careful: rust *really* wants to optimize STAGE3_ENTRY into a u16
    // in the resulting binary
    let mut buf_address: u32;
    unsafe {
        core::arch::asm!(
            "mov {1}, {0}",
            in(reg) STAGE3_ENTRY,
            out(reg) buf_address,
        );
    }
    buf_address -= (BOOT_SEGMENT as u32) << 4;