1 files changed, 78 insertions, 0 deletions
diff --git a/example.c b/example.c
new file mode 100644
index 0000000..15388be
--- /dev/null
+++ b/example.c
@@ -0,0 +1,78 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+// Example kernel
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned long u32;
+
+struct vid_info {
+	u32 mode;
+	u32 *vbe;
+};
+
+enum mmap_type {
+	MEMORY_AVAILABLE = 1,
+	MEMORY_RESERVED,
+	MEMORY_ACPI,
+	MEMORY_NVS,
+	MEMORY_DEFECT,
+	MEMORY_DISABLED
+};
+
+struct mmap_boot {
+	u32 lbase;
+	u32 hbase;
+	u32 lsize;
+	u32 hsize;
+	u32 type;
+	u32 acpi;
+};
+
+struct mem_info {
+	struct mmap_boot *start;
+	u32 *end;
+	u32 size;
+};
+
+struct boot_info {
+	struct vid_info *vid;
+	struct mem_info *mem;
+	u32 tss;
+	u32 drive;
+};
+
+struct vbe_basic {
+	u8 stuff1[16];
+	u16 pitch;
+	u16 width;
+	u16 height;
+	u8 stuff2[18];
+	u8 *fb;
+	u8 stuff3[212];
+};
+
+int kernel_main(struct boot_info *boot);
+int kernel_main(struct boot_info *boot)
+{
+	// Fill screen with rgba colors
+	u32 colors[7] = { 0xff0000, 0xffa500, 0xffff00, 0x008000, 0x0000ff, 0x4b0082, 0xee82ee };
+	struct vbe_basic *vbe = (void *)boot->vid->vbe;
+	u8 *draw = vbe->fb;
+	for (u32 y = 0; y < vbe->height; y++) {
+		u32 color = colors[y / (vbe->height / 7)];
+		for (u32 x = 0; x < vbe->width; x++) {
+			draw[4 * x] = color >> 0 & 0xff;
+			draw[4 * x + 1] = color >> 8 & 0xff;
+			draw[4 * x + 2] = color >> 16 & 0xff;
+			draw[4 * x + 3] = 0xff; // Alpha is always 0xff in this example
+		}
+		draw += vbe->pitch;
+	}
+
+	// Idle
+	__asm__ volatile("cli");
+	while (1)
+		__asm__ volatile("hlt");
+
+	return 1;
+}