Writing an OS in Rust

• 打印字符串
• 目标配置清单
• 编译内核
• 创建引导映像
• qemu启动内核

vi src/main.rs

#[no_mangle]
pub extern "C" fn _start() -> ! {
    let vga = 0xb8000 as *mut u8;
    let b: &[u8] = b"Hello World";
    for (i, &byte) in b.iter().enumerate() {
        unsafe {
            *vga.offset(i as isize * 2) = byte;
            *vga.offset(i as isize * 2 + 1) = 0xb;
        }
    }
    loop {}
}

vi x86_64.json

{
    "llvm-target": "x86_64-unknown-none",
    "data-layout": "e-m:e-i64:64-f80:128-n8:16:32:64-S128",
    "arch": "x86_64",
    "target-endian": "little",
    "target-pointer-width": "64",
    "target-c-int-width": "32",
    "os": "none",
    "executables": true,
    "linker-flavor": "ld.lld",
    "linker": "rust-lld",
    "panic-strategy": "abort",
    "disable-redzone": true,
    "features": "-mmx,-sse,+soft-float"
}

vi Cargo.toml

[package.metadata.bootimage]
build-command = ["xbuild"]

[dependencies]
bootloader = "0.9.22"

vi .cargo/config

[build]
target = "x86_64.json"

[target.'cfg(target_os = "none")']
runner = "bootimage runner"

qemu

cargo xbuild
cargo bootimage
cargo xrun
qemu-system-x86_64.exe -drive format=raw,file=target\x86_64\debug\bootimage-he.bin