int db_free(db_t db, size_t n) {
long base;
base = db;
demand(!db_isfree(base, n), Blocks not allocated.);
Bit_clear(free_map, base, base + n - 1);
return base;
}
/* puts each element into bit vector to check digits */
void check_setof9(int col, int row, UArray2_T a, void *elem, void *bit)
{
int digit = *(int *)elem;
Bit_T b = bit;
if (digit < 1 || digit > 9) {
Bit_free(&b);
UArray2_free(&a);
exit(1);
/* digit is already in vector */
} if (Bit_get(bit, digit) == 1) {
Bit_free(&b);
UArray2_free(&a);
exit(1);
/* if digit isn't in vector, change bit to 1 */
} else {
Bit_put(bit, digit, 1);
/*all nine digits are present, reset bit vector*/
} if (Bit_count(bit) == 9) {
Bit_clear(bit, 1, 9);
}
(void) col;
(void) row;
(void) a;
}
void kernel_init(void) {
static int init;
pmap_start = 1;
if(init) {
Bit_clear(free_map, 0, XN_NBLOCKS-1);
return;
}
init = 1;
pages = (void *)malloc(XN_BLOCK_SIZE * (PHYS_MEM+1));
assert(pages);
pages = (void *)roundup((unsigned)pages, XN_BLOCK_SIZE);
demand((unsigned) pages % XN_BLOCK_SIZE == 0, Bogus alignment);
pmap = Bit_new(PHYS_MEM);
free_map = Bit_new(XN_NBLOCKS);
demand(db_isfree(0, 1), should have allocated);
db_alloc(0, 1);
demand(!db_isfree(0, 1), should have allocated);
}
void pfree(ppn_t base, size_t npages) {
printf("freeing [%ld, %ld)\n", base, base + npages);
demand(!Bit_off(pmap, base, base + npages), pages not allocated.);
Bit_clear(pmap, base, base + npages - 1);
}
