#include <mango/libc/string.h>
#include <arch/gdt.h>

static void init_entry(struct gdt_entry *entry, int access, int flags)
{
	entry->ge_limit_low = 0xFFFF;
	entry->ge_base_low = 0x00;
	entry->ge_base_mid = 0x00;
	entry->ge_access = access;
	entry->ge_gran = flags;
	entry->ge_base_hi = 0x00;
}

int gdt_init(struct gdt *gdt, struct gdt_ptr *gdtp)
{
	memset(&gdt->g_entries[0], 0x0, sizeof gdt->g_entries[0]);

	init_entry(&gdt->g_entries[1], GDT_A_PRESENT | GDT_A_CODEREAD | GDT_A_CODE, GDT_F_64BIT);
	init_entry(&gdt->g_entries[2], GDT_A_PRESENT | GDT_A_DATAWRITE | GDT_A_DATA, GDT_F_64BIT);
	init_entry(&gdt->g_entries[3], GDT_A_PRESENT | GDT_A_USER | GDT_A_CODEREAD | GDT_A_CODE, GDT_F_64BIT);
	init_entry(&gdt->g_entries[4], GDT_A_PRESENT | GDT_A_USER | GDT_A_DATAWRITE | GDT_A_DATA, GDT_F_64BIT);

	gdtp->g_ptr = (uint64_t)gdt;
	gdtp->g_limit = sizeof(*gdt) - 1;

	return 0;
}