Add os runner to justfile

Writes "Gamarjoba, munde!" to the VGA text buffer

justfile

@@ -1,6 +1,12 @@
 default:
     just --list
 
+execute_rust_os:
+    #!/usr/bin/env bash
+    cd os-in-rust
+    cargo bootimage
+    qemu-system-x86_64 -drive format=raw,file=target/x86_64_target/debug/bootimage-os-in-rust.bin
+
 run_gamarjoba: build_gamarjoba
     ./gamarjoba_munde/gamarjoba
 

os-in-rust/.cargo/config.toml

@@ -0,0 +1,6 @@
+[unstable]
+build-std = ["core", "compiler_builtins"]
+build-std-features = ["compiler-builtins-mem"]
+
+[build]
+target = "x86_64_target.json"

os-in-rust/Cargo.lock

@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "bootloader"
+version = "0.9.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a62c8f6168cd106687ee36a2b71a46c4144d73399f72814104d33094b8092fd2"
+
 [[package]]
 name = "os-in-rust"
 version = "0.1.0"
+dependencies = [
+ "bootloader",
+]

os-in-rust/Cargo.toml

@@ -5,10 +5,6 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[profile.dev]
-panic = "abort"
-
-[profile.release]
-panic = "abort"
-
 [dependencies]
+#bootloader = "0.10.12"
+bootloader = "0.9.8"

os-in-rust/src/main.rs

@@ -8,8 +8,23 @@ fn panic(_info: &PanicInfo) -> ! {
     loop {}
 }
 
+static GAMARJOBA: &[u8] = b"Gamarjoba, MVNDE!";
+
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
+    let vga_buffer = 0xb8000 as *mut u8;
+
+    for (i, &byte) in GAMARJOBA.iter().enumerate() {
+        let i = i as isize;
+        unsafe {
+            *vga_buffer.offset(i * 2) = byte;
+            *vga_buffer.offset(i * 2 + 1) = 0xd;
+
+
+        }
+
+    }
+
     loop {}
 }
 

os-in-rust/x86_64_target.json

@@ -0,0 +1,18 @@
+{
+    "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"
+}