pjht
3ca8b5a232
Exit function does not deallocate task memory except for the data block, and does not are about the exit code except for logging.
91 lines
1.9 KiB
C
91 lines
1.9 KiB
C
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
#include <stdint.h>
|
|
|
|
static char bitmap[2097152];
|
|
static void* data=(void*)0xFE800000;
|
|
|
|
|
|
static char get_bmap_bit(uint32_t index) {
|
|
uint32_t byte=index/8;
|
|
uint32_t bit=index%8;
|
|
char entry=bitmap[byte];
|
|
return (entry&(1<<bit))>0;
|
|
}
|
|
|
|
static void set_bmap_bit(uint32_t index) {
|
|
uint32_t byte=index/8;
|
|
uint32_t bit=index%8;
|
|
bitmap[byte]=bitmap[byte]|(1<<bit);
|
|
}
|
|
|
|
static void clear_bmap_bit(uint32_t index) {
|
|
uint32_t byte=index/8;
|
|
uint32_t bit=index%8;
|
|
bitmap[byte]=bitmap[byte]&(~(1<<bit));
|
|
}
|
|
|
|
void* kmalloc(uint32_t size) {
|
|
uint32_t num_4b_grps=(uint32_t)ceilf((float)size/4);
|
|
num_4b_grps+=2;
|
|
uint32_t bmap_index;
|
|
uint32_t remaining_blks;
|
|
for(uint32_t i=0;i<2097152;i++) {
|
|
char got_0=0;
|
|
remaining_blks=num_4b_grps;
|
|
uint32_t old_j;
|
|
for (uint32_t j=i*8;;j++) {
|
|
char bit=get_bmap_bit(j);
|
|
if (got_0) {
|
|
if (bit) {
|
|
if (remaining_blks==0) {
|
|
bmap_index=old_j;
|
|
break;
|
|
} else {
|
|
i+=j/8;
|
|
i--;
|
|
break;
|
|
}
|
|
} else {
|
|
remaining_blks--;
|
|
}
|
|
} else {
|
|
if (!bit) {
|
|
got_0=1;
|
|
old_j=j;
|
|
remaining_blks--;
|
|
}
|
|
}
|
|
if (remaining_blks==0) {
|
|
bmap_index=old_j;
|
|
break;
|
|
}
|
|
}
|
|
if (remaining_blks==0) {
|
|
break;
|
|
}
|
|
}
|
|
if (remaining_blks!=0) {
|
|
return NULL;
|
|
}
|
|
for (uint32_t i=0;i<num_4b_grps;i++) {
|
|
set_bmap_bit(bmap_index+i);
|
|
}
|
|
uint32_t data_offset=(bmap_index*8)+8;
|
|
uint32_t* info=(void*)(((char*)data)+data_offset-8);
|
|
info[0]=num_4b_grps;
|
|
info[1]=bmap_index;
|
|
return (void*)(((char*)data)+data_offset);
|
|
|
|
}
|
|
|
|
void kfree(void* mem) {
|
|
uint32_t* info=(uint32_t*)((uint32_t)mem-8);
|
|
uint32_t num_4b_grps=info[0];
|
|
uint32_t bmap_index=info[1];
|
|
for (uint32_t i=0;i<num_4b_grps;i++) {
|
|
clear_bmap_bit(bmap_index+i);
|
|
}
|
|
}
|