Add the beginning of support for kernel graphics to bootloader.

* Load a font file off disk to pass to kernel
* Expose a framebuffer to the kernel
* Currently the kernel just paints the screen red

src/modules/main/main.c

@@ -1,7 +1,46 @@
+#include <stddef.h>
+#include <stdint.h>
+
 void do_the_set_registers();
 
+#pragma pack(push, 1)
+struct popcorn_data {
+	uint32_t magic;
+	uint16_t version;
+	uint16_t length;
+
+	uint32_t _reserverd0;
+	uint32_t flags;
+
+	void *font;
+	size_t font_length;
+
+	void *data;
+	size_t data_length;
+
+	void *memory_map;
+	void *runtime;
+
+	void *acpi_table;
+
+	void *frame_buffer;
+	size_t frame_buffer_size;
+	uint32_t hres;
+	uint32_t vres;
+	uint32_t rmask;
+	uint32_t gmask;
+	uint32_t bmask;
+	uint32_t _reserved1;
+}
+__attribute__((aligned(8)));
+#pragma pack(pop)
+
 void
-kernel_main(void *header)
+kernel_main(struct popcorn_data *header)
 {
+	uint32_t *p = header->frame_buffer;
+	uint32_t *end = p + (header->frame_buffer_size / sizeof(uint32_t));
+	while (p < end) *p++ = header->rmask;
+
 	do_the_set_registers(header);
 }