VGA Z-buffer is now dynamically allocated and freed

memory management can reuse the last pointer malloced if freed again

1 files changed, 13 insertions, 2 deletions

diff --git a/src/kernel/memorymanagement.c b/src/kernel/memorymanagement.c
index dc2d160..b8a84b2 100644
--- a/src/kernel/memorymanagement.c
+++ b/src/kernel/memorymanagement.c
@@ -11,6 +11,7 @@ void memory_manager_init( memory_manager_t *memory_manager, size_t offset, size_
 	memory_manager->offset = offset;
 	memory_manager->size = size;
 	memory_manager->free_ptr = offset;
+	memory_manager->prev_ptr = 0xFFFFFFFF;
 }
 
 void *memory_manager_allocate( memory_manager_t *memory_manager, size_t size )
@@ -19,10 +20,11 @@ void *memory_manager_allocate( memory_manager_t *memory_manager, size_t size )
 
 	if( memory_manager->free_ptr - memory_manager->offset + size > memory_manager->size ) {
 		kernel_panic( "Heap allocation out of memory (requested %d bytes, available %d)",
-			size, size - ( memory_manager->free_ptr - memory_manager->offset ) - 1 );
+			size, size - ( memory_manager->free_ptr - memory_manager->offset ) );
 	}
 
 	p = (void *)memory_manager->free_ptr;
+	memory_manager->prev_ptr = memory_manager->free_ptr;
 	memory_manager->free_ptr += size;
 
 	return p;
@@ -34,7 +36,16 @@ void memory_manager_deallocate( memory_manager_t *memory_manager, void **p )
 		kernel_panic( "Double free of pointer 0x%X in heap", *p );
 	}
 
-	*p = NULL;
+	// This actually doesn't work and we do it outside after free, when
+	// a buffer has an optional semantic
+	//*p = NULL;
+	
+	// are we freeing the previously allocated block, if yes, we can
+	// adjust the free pointer
+	if( (uint32_t)*p == memory_manager->prev_ptr ) {
+		memory_manager->free_ptr = memory_manager->prev_ptr;
+		memory_manager->prev_ptr = 0xFFFFFFFF;
+	}
 }