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/* SPDX-License-Identifier: MIT */
#include "heapblock.h"
#include "assert.h"
#include "types.h"
#include "utils.h"
#include "xnuboot.h"
/*
* This is a non-freeing allocator, used as a backend for malloc and for uncompressing data.
*
* Allocating 0 bytes is allowed, and guarantees "infinite" (until the end of RAM) space is
* available at the returned pointer as long as no other malloc/heapblock calls occur, which is
* useful as a buffer for unknown-length uncompressed data. A subsequent call with a size will then
* actually reserve the block.
*/
static void *heap_base;
void heapblock_init(void)
{
void *top_of_kernel_data = (void *)cur_boot_args.top_of_kernel_data;
heap_base = top_of_kernel_data;
heapblock_alloc(0); // align base
printf("Heap base: %p\n", heap_base);
}
void *heapblock_alloc(size_t size)
{
return heapblock_alloc_aligned(size, 64);
}
void *heapblock_alloc_aligned(size_t size, size_t align)
{
assert((align & (align - 1)) == 0);
assert(heap_base);
uintptr_t block = (((uintptr_t)heap_base) + align - 1) & ~(align - 1);
heap_base = (void *)(block + size);
return (void *)block;
}
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