42_KFS/src/memory/memory.c

#include "memory.h"
#include "debug.h"
#include "kprintf.h"

#include <stdint.h>

uint32_t *page_directory = &boot_page_directory;
uint32_t page_table_default[1024] __attribute__((aligned(4096)));

static void alloc_page_tables(void)
{
	uint32_t *frame_ptr = NULL;
	for (int16_t i = 1; i < 768; i++) {
		uint32_t *page_table = alloc_pages(PAGE_SIZE, &frame_ptr);
		for (int16_t j = 0; j < 1024; j++)
			page_table[j] = j << 12 | 0x03;
		page_directory[i] = ((uint32_t)frame_ptr & PAGE_MASK) | 0x03;
	}
}

void init_memory(void)
{
	assert(page_directory);
	for (int16_t i = 0; i < 0x300; i++)
		page_directory[i] = 0x02;
	for (int16_t i = 0; i < 1024; i++)
		page_table_default[i] = (i << 12) | 0x03;
	page_directory[0] = ((uint32_t)page_table_default - HEAP_END) | 0x03;
	alloc_page_tables();
}