memblock can now self re-allocate its internal buffers

memory allocated by memblock_alloc() can now be limited to a certain region.

sandbox/base/main.c

@@ -2,11 +2,15 @@
 #include <stddef.h>
 #include <inttypes.h>
 #include <sys/mman.h>
+#include <socks/types.h>
 #include <socks/memblock.h>
 
 /* we're working with 4MiB of simulated system RAM */
 #define MEMORY_SIZE_MB 128
 
+#define ALLOC_START_MB 16
+#define ALLOC_END_MB 18
+
 /* virtual address of where system memory is mapped */
 static void *system_memory = NULL;
 
@@ -33,6 +37,12 @@ int main(int argc, const char **argv)
 
 	printf("allocated %u MiB (0x%zx bytes) of memory to act as system RAM at %p\n", MEMORY_SIZE_MB, MB_TO_BYTES(MEMORY_SIZE_MB), system_memory);
 
+	uintptr_t voffset = (uintptr_t)system_memory;
+
+	memblock_init(MB_TO_BYTES(ALLOC_START_MB) + voffset, MB_TO_BYTES(ALLOC_END_MB) + voffset, voffset);
+
+	printf("memblock heap initialised in 0x%zx-0x%zx\n", MB_TO_BYTES(ALLOC_START_MB), MB_TO_BYTES(ALLOC_END_MB));
+
 	memblock_add(0, MB_TO_BYTES(MEMORY_SIZE_MB));
 
 	memblock_reserve(0x00000, 0x40000);