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#include <memory/mmap.h>
#include <stddef.h>
#include <stdint.h>
#include <system.h>
#define FRAME_SIZE 0x1000
#define FRAME_COUNT (total_memory / 4)
#define FRAME_TABLE_SIZE (FRAME_COUNT / 32)
#define FREE 0x0
#define USED 0x1
void *kmalloc(u32 size);
extern u32 kernel_end;
u32 kernel_end_address = (u32)&kernel_end;
u32 total_memory;
u32 *frame_table;
// Not to be used externally!
void *kmalloc(u32 size)
{
void *ret;
ret = (void *)kernel_end_address;
kernel_end_address += size;
return ret;
}
// TODO: Efficiency
void *kmalloc_frames(u32 num)
{
u8 found;
for (u32 i = 0; i < FRAME_COUNT; i++) {
found = 1;
for (u32 j = 0; j < num; j++) {
if (mmap_index_check(i + j) == USED) {
found = 0;
break;
}
}
if (found) {
for (u32 j = 0; j < num; j++) {
mmap_index_set_used(i + j);
}
return (void *)(i * FRAME_SIZE);
}
}
warn("Not enough frames");
return NULL;
}
void kfree_frames(void *ptr, u32 num)
{
u32 address = (u32)ptr;
u32 i = address;
while (i < address + (num * FRAME_SIZE)) {
mmap_address_set_free(address);
i += FRAME_SIZE;
}
}
u8 mmap_index_check(u32 n)
{
return (frame_table[n / 32] >> (n % 32)) & 0x1;
}
void mmap_init(u32 size)
{
total_memory = size;
frame_table = kmalloc(FRAME_TABLE_SIZE);
}
void mmap_init_finalize()
{
// TODO: Efficiency
//memset(frame_table, 0xFF, (&kernel_end / FRAME_SIZE) / 8);
for (u32 i = 0; i < kernel_end_address; i += FRAME_SIZE) {
mmap_address_set_used(i);
}
}
void mmap_address_set_free(u32 address)
{
frame_table[(address / FRAME_SIZE) / 32] &= ~(1 << ((address / FRAME_SIZE) % 32));
}
void mmap_address_set_used(u32 address)
{
frame_table[(address / FRAME_SIZE) / 32] |= (1 << ((address / FRAME_SIZE) % 32));
}
void mmap_index_set_free(u32 n)
{
frame_table[n / 32] &= ~(1 << (n % 32));
}
void mmap_index_set_used(u32 n)
{
frame_table[n / 32] |= 1 << (n % 32);
}
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