void* Buddy_Alloc(Buddy_Heap* h, size_t size, int zeroFill) {
register int j, k;
Buddy_FreeListNode *L, *R;
int* p;
if (size +sizeof(Buddy_FreeListNode) > (1<<h->M)) return NULL;
j= k= Roundup(Max(size +sizeof(L->size), sizeof(Buddy_FreeListNode))); /* find k with 2^(k-1) < size <= 2^k */
cli(); /* b'cause freeList[] etc are shard vars !!! */
while ((j <=h->M) && (h->freeList[j].forward == &h->freeList[j])) /* R1: {find free block} */
j++;
if (j <=h->M) { /* R2: remove block (i.e. first list entry) from freeList */
L= h->freeList[j].forward;
h->freeList[j].forward= L->forward;
L->forward->backward= (Buddy_FreeListNode*)&h->freeList[j];
L->size= k; /* tag block as reserved */
while (j != k) { /* R3: split required ? */
j--; /* R4: yes, split ! */
R= (void*)L +(1<<j);
R->size= -j; /* mark block as free with its negative size */
R->forward= R->backward= (Buddy_FreeListNode*)&h->freeList[j]; /* insert free block with size j in freeList */
h->freeList[j].forward= h->freeList[j].backward = R;
}
//RTK_RestoreIntsEnable;
if (zeroFill) { /* initialize block with zeros */
p= ((int*)L) +sizeof(L->size);
for (j= 0; j <size; j++) *p++= 0;
}
return ((void*)L) +sizeof(L->size); /* available block starts at (L+1) */
}
else { /* no available block with size k */
//RTK_RestoreIntsEnable;
return 0; /* signal out of heap space */
}
}
/*
* Figure out how much real memory is available.
* Start looking from the megabyte after the end of the kernel data,
* until we find non-memory.
*/
vaddr_t
size_memory()
{
unsigned int *volatile look;
unsigned int *max;
#if 0
extern char *end;
#endif
#define PATTERN 0x5a5a5a5a
#define STRIDE (4*1024) /* 4k at a time */
#define Roundup(value, stride) (((unsigned)(value) + (stride) - 1) & ~((stride)-1))
/*
* count it up.
*/
max = (void *)MAXPHYSMEM;
#if 0
for (look = (void *)Roundup(end, STRIDE); look < max;
#else
for (look = (void *)first_addr; look < max;
#endif
look = (int *)((unsigned)look + STRIDE)) {
unsigned save;
/* if can't access, we've reached the end */
if (badwordaddr((vaddr_t)look)) {
#if defined(DEBUG)
printf("%x\n", look);
#endif
look = (int *)((int)look - STRIDE);
break;
}
/*
* If we write a value, we expect to read the same value back.
* We'll do this twice, the 2nd time with the opposite bit
* pattern from the first, to make sure we check all bits.
*/
save = *look;
if (*look = PATTERN, *look != PATTERN)
break;
if (*look = ~PATTERN, *look != ~PATTERN)
break;
*look = save;
}
return (trunc_page((unsigned)look));
}
