Files
nub-os-2/src/boot/main.c
2025-12-30 23:07:39 +01:00

55 lines
1.5 KiB
C

#include "console.h"
#include "multiboot2.h"
#include <def.h>
#include "console.h"
#include "multiboot2.h"
#include "panic.h"
#include "util.h"
#define MAX_REGIONS 64
typedef struct {
u64 base_address;
u64 length;
} memory_region;
extern uptr kernel_start;
extern uptr kernel_end;
static memory_region memory_regions[MAX_REGIONS] = {0};
static size_t memory_region_count = 0;
static void find_memory_regions(uptr multiboot_info) {
multiboot_tag_mmap *tag = multiboot_get_mmap(multiboot_info);
if (tag == NULL) {
boot_panic("Multiboot did not provide mmap tag");
}
u32 entry_count = (tag->size - 16) / tag->entry_size;
u8 *entry_ptr = (u8*)tag->entries;
for (u32 i = 0; i < entry_count; ++i) {
multiboot_mmap_entry *entry = (multiboot_mmap_entry*)entry_ptr;
if (entry->type == MULTIBOOT_MEMORY_AVAILABLE) {
if (memory_region_count >= MAX_REGIONS) {
boot_panic("Too many memory regions");
}
memory_regions[memory_region_count++] = (memory_region){ entry->base_address, entry->length };
}
entry_ptr += tag->entry_size;
}
}
// We are now in long mode with kernel pages and vga buffer identity mapped
void x86_64_main(uptr multiboot_info) {
console_clear();
find_memory_regions(multiboot_info);
for (u32 i = 0; i < memory_region_count; ++i) {
kprintf("region: base_address=0x%X, length=0x%X\n", memory_regions[i].base_address, memory_regions[i].length);
}
}