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#include <types.h>
#include <multiboot2.h>
#include <graphics.h>
#include <debug.h>
#define KERNEL_VMA 0xc0000000
/* https://www.gnu.org/software/grub/manual/multiboot2/html_node/Boot-information-format.html */
void init_fb(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic)
{
if (multiboot_magic != MB2_MAGIC) {
// not loaded by multiboot2 bootloader
__asm__ volatile ("hlt;");
}
// we will store framebuffer information here
static mb2_tag_fb* tag_fb;
// skip first 8 bytes (total_size + reserved)
mb2_tag_header* tag_header = (mb2_tag_header*)((char*)multiboot_bootinfo + 8 + KERNEL_VMA);
bochs_breakpoint();
while (tag_header->type != MB2_TAG_END) {
// process tag_type
switch(tag_header->type) {
case MB2_TAG_FB:
tag_fb = (mb2_tag_fb*)tag_header;
break;
default:
break;
}
// next mb2_tag
tag_header += tag_header->size / 8 + ((tag_header->size % 8) > 0);
}
main_fb.addr = tag_fb->framebuffer_addr;
main_fb.width = tag_fb->framebuffer_width;
main_fb.height = tag_fb->framebuffer_height;
main_fb.pitch = tag_fb->framebuffer_pitch;
main_fb.bpp = tag_fb->framebuffer_bpp;
}
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