initial commit

.cargo/config.toml

@@ -0,0 +1,5 @@
+[build]
+target = "arm-none-eabihf.json"
+[unstable]
+build-std-features = ["compiler-builtins-mem"]
+build-std = ["core", "compiler_builtins"]

.gitignore

@@ -0,0 +1 @@
+/target

Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "jank_os"
+version = "0.1.0"

Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "jank_os"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

arm-none-eabihf.json

@@ -0,0 +1,28 @@
+{
+  "llvm-target": "arm-none-eabihf",
+  "target-endian": "little",
+  "target-pointer-width": "32",
+  "target-c-int-width": "32",
+  "os": "none",
+  "env": "eabi",
+  "vendor": "unknown",
+  "arch": "arm",
+  "panic-strategy": "abort",
+  "llvm-floatabi": "hard",
+  "disable-redzone": true,
+  "linker-flavor": "gcc",
+  "linker": "arm-none-eabi-gcc",
+  "pre-link-args": {
+    "gcc": [
+      "-Wall",
+      "-nostdlib",
+      "-nostartfiles",
+      "-ffreestanding",
+      "-march=armv6"
+    ]
+  },
+  "features": "+strict-align,+v6,+vfp2,-d32",
+  "data-layout": "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64",
+  "executables": true,
+  "relocation-model": "static"
+}

notes.md

@@ -0,0 +1,11 @@
+build: `cargo build --target arm-none-eabihf.json -Z build-std=core,compiler_builtins`
+
+qemu: `qemu-system-arm -m 256 -M raspi0 -serial stdio -kernel kernel.elf`
+
+---
+
+# References
+
+- https://os.phil-opp.com/minimal-rust-kernel/
+- https://wiki.osdev.org/Raspberry_Pi_Bare_Bones
+- https://wiki.osdev.org/Raspberry_Pi_Bare_Bones_Rust

src/main.rs

@@ -0,0 +1,26 @@
+#![no_std]
+#![no_main]
+
+use core::panic::PanicInfo;
+
+/// This function is called on panic.
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+    loop {}
+}
+
+static HELLO: &[u8] = b"Hello World!";
+
+#[unsafe(no_mangle)]
+pub extern "C" fn _start() -> ! {
+    let vga_buffer = 0xb8000 as *mut u8;
+
+    for (i, &byte) in HELLO.iter().enumerate() {
+        unsafe {
+            *vga_buffer.offset(i as isize * 2) = byte;
+            *vga_buffer.offset(i as isize * 2 + 1) = 0xb;
+        }
+    }
+
+    loop {}
+}