Build upon the limine Rust template and a working pipeline, display an orange background on load.

kernel/src/graphics.rs

@@ -0,0 +1,25 @@
+use limine::framebuffer::Framebuffer;
+
+pub fn rgb(r: u8, g: u8, b: u8) -> u32 {
+    ((r as u32) << 16) | ((g as u32) << 8) | (b as u32)
+}
+
+pub fn create_rect(framebuffer: &Framebuffer, x: u64, y: u64, width: u64, height: u64, color: u32) {
+    for fb_x in x..x+width {
+        for fb_y in y..y+height {
+            // Calculate the pixel offset using the framebuffer information we obtained above.
+            // We skip `i` scanlines (pitch is provided in bytes) and add `i * 4` to skip `i` pixels forward.
+            let bytes_per_pixel = framebuffer.bpp() as u64 / 8;
+            let pixel_offset = fb_y * framebuffer.pitch() + fb_x * bytes_per_pixel;
+
+            // Write 0xFFFFFFFF to the provided pixel offset to fill it white.
+            unsafe {
+                framebuffer
+                    .addr()
+                    .add(pixel_offset as usize)
+                    .cast::<u32>()
+                    .write(color)
+            };
+        }
+    }
+}

kernel/src/main.rs

@@ -0,0 +1,64 @@
+#![no_std]
+#![no_main]
+
+use core::arch::asm;
+
+use limine::BaseRevision;
+use limine::request::{FramebufferRequest, RequestsEndMarker, RequestsStartMarker};
+
+mod graphics;
+use crate::graphics::*;
+
+
+/// Sets the base revision to the latest revision supported by the crate.
+/// See specification for further info.
+/// Be sure to mark all limine requests with #[used], otherwise they may be removed by the compiler.
+#[used]
+// The .requests section allows limine to find the requests faster and more safely.
+#[unsafe(link_section = ".requests")]
+static BASE_REVISION: BaseRevision = BaseRevision::new();
+
+#[used]
+#[unsafe(link_section = ".requests")]
+static FRAMEBUFFER_REQUEST: FramebufferRequest = FramebufferRequest::new();
+
+/// Define the stand and end markers for Limine requests.
+#[used]
+#[unsafe(link_section = ".requests_start_marker")]
+static _START_MARKER: RequestsStartMarker = RequestsStartMarker::new();
+#[used]
+#[unsafe(link_section = ".requests_end_marker")]
+static _END_MARKER: RequestsEndMarker = RequestsEndMarker::new();
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn kmain() -> ! {
+    // All limine requests must also be referenced in a called function, otherwise they may be
+    // removed by the linker.
+    assert!(BASE_REVISION.is_supported());
+
+    if let Some(framebuffer_response) = FRAMEBUFFER_REQUEST.get_response() {
+        if let Some(framebuffer) = framebuffer_response.framebuffers().next() {
+            graphics::create_rect(&framebuffer, 0, 0, framebuffer.width(), framebuffer.height(), graphics::rgb(253, 129, 0));
+        }
+    }
+
+    hcf();
+}
+
+#[panic_handler]
+fn rust_panic(_info: &core::panic::PanicInfo) -> ! {
+    hcf();
+}
+
+fn hcf() -> ! {
+    loop {
+        unsafe {
+            #[cfg(target_arch = "x86_64")]
+            asm!("hlt");
+            #[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))]
+            asm!("wfi");
+            #[cfg(target_arch = "loongarch64")]
+            asm!("idle 0");
+        }
+    }
+}