diff --git a/src/blitter/ntapi_blt_alloc.c b/src/blitter/ntapi_blt_alloc.c
index 92a84e9..c4b69e5 100644
--- a/src/blitter/ntapi_blt_alloc.c
+++ b/src/blitter/ntapi_blt_alloc.c
@@ -79,8 +79,7 @@ int32_t __fastcall __ntapi_blt_alloc(
 
 	if (!(params->flags & NT_BLITTER_PRESERVE_BITS))
 		__ntapi->tt_aligned_block_memset(
-			blt_ctx->bitmap,
-			0xFFFFFFFFFFFFFFFF,
+			blt_ctx->bitmap,(-1),
 			ptrs * sizeof(uintptr_t));
 
 	/* info structure */