examples: add 'Hello World' no-std example

.cargo/config.toml

@@ -21,4 +21,5 @@ oro-ra-x86_64 = "check --quiet --message-format=json --keep-going --target ./oro
 
 oro-ra-aarch64 = "check --quiet --message-format=json --keep-going --target ./oro-arch-aarch64/aarch64-unknown-oro.json --bin oro-kernel-aarch64 --bin oro-limine-aarch64 -Zunstable-options -Zbuild-std=core,compiler_builtins,alloc -Zbuild-std-features=compiler-builtins-mem"
 
-oro-examples = "build --target=x86_64-unknown-none --target=aarch64-unknown-none -p example-noop -p example-spin -p example-std-noop -p example-std-noop-nightly -p example-std-spin"
+# NOTE: Does not need the unstable flags / building std / etc.
+oro-examples = "build --target=x86_64-unknown-none --target=aarch64-unknown-none -p example-noop -p example-spin -p example-std-noop -p example-std-noop-nightly -p example-std-spin -p example-hello-world"

Cargo.toml

@@ -35,6 +35,7 @@ members = [
 	# Examples
 	"examples/no-std/noop",
 	"examples/no-std/spin",
+	"examples/no-std/hello-world",
 	"examples/std/noop",
 	"examples/std/noop-nightly",
 	"examples/std/spin",

examples/no-std/hello-world/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "example-hello-world"
+description = "Example module that prints Hello World to the kernel logger."
+version = "0.0.0"
+publish = false
+edition = "2021"
+
+build = "build.rs"
+
+[dependencies.oro]
+path = "../../../oro"
+features = ["runtime"]
+
+[build-dependencies.oro]
+path = "../../../oro"
+features = ["build"]
+default-features = false

examples/no-std/hello-world/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+	::oro::build();
+}

examples/no-std/hello-world/src/main.rs

@@ -0,0 +1,51 @@
+#![no_std]
+#![no_main]
+
+use oro::{id::kernel::iface::ROOT_DEBUG_OUT_V0, syscall};
+
+fn write_bytes(bytes: &[u8]) {
+	if bytes.len() == 0 {
+		return;
+	}
+
+	let mut word = bytes[0] as u64;
+
+	for i in 1..bytes.len() {
+		if i % 8 == 0 {
+			// XXX(qix-): Hard coding the ID for a moment, bear with.
+			syscall::set!(
+				ROOT_DEBUG_OUT_V0,
+				4294967296,
+				0,
+				syscall::key!("write"),
+				word
+			)
+			.unwrap();
+			word = 0;
+		}
+
+		word = (word << 8) | bytes[i] as u64;
+	}
+
+	if bytes.len() % 8 != 0 {
+		// Shift it the remaining bits.
+		word <<= 8 * (8 - (bytes.len() % 8));
+		syscall::set!(
+			ROOT_DEBUG_OUT_V0,
+			4294967296,
+			0,
+			syscall::key!("write"),
+			word
+		)
+		.unwrap();
+	}
+}
+
+fn write_str(s: &str) {
+	write_bytes(s.as_bytes());
+}
+
+#[no_mangle]
+fn main() {
+	write_str("Hello, Oro!\n");
+}