diff --git a/src/cgif_raw.c b/src/cgif_raw.c
index 3f9ed95..b059ccc 100644
--- a/src/cgif_raw.c
+++ b/src/cgif_raw.c
@@ -323,8 +323,8 @@ static int LZW_GenerateStream(LZWResult* pResult, const uint32_t numPixel, const
   // pack the generated LZW data into blocks of 255 bytes
   uint8_t *byteList; // lzw-data packed in byte-list
   uint8_t *byteListBlock; // lzw-data packed in byte-list with 255-block structure
-  uint64_t MaxByteListLen = MAX_CODE_LEN*lzwPos/8ul +2ul +1ul; // conservative upper bound
-  uint64_t MaxByteListBlockLen = MAX_CODE_LEN*lzwPos*(BLOCK_SIZE+1ul)/8ul/BLOCK_SIZE +2ul +1ul +1ul; // conservative upper bound
+  uint64_t MaxByteListLen = MAX_CODE_LEN * lzwPos / 8ull + 2ull + 1ull; // conservative upper bound
+  uint64_t MaxByteListBlockLen = MAX_CODE_LEN * lzwPos * (BLOCK_SIZE + 1ull) / 8ull / BLOCK_SIZE + 2ull + 1ull +1ull; // conservative upper bound
   byteList      = malloc(MaxByteListLen); // TBD check return value of malloc
   byteListBlock = malloc(MaxByteListBlockLen); // TBD check return value of malloc
   bytePos       = create_byte_list(byteList,lzwPos, pContext->pLZWData, initDictLen, initCodeLen);