diff --git a/lib/zstd.h b/lib/zstd.h
index 986b81980..deedd3643 100644
--- a/lib/zstd.h
+++ b/lib/zstd.h
@@ -381,7 +381,9 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void);   /*!< recommended size for output
 #define ZSTD_WINDOWLOG_MIN      10
 #define ZSTD_HASHLOG_MAX      ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30)
 #define ZSTD_HASHLOG_MIN         6
-#define ZSTD_CHAINLOG_MAX     ((ZSTD_WINDOWLOG_MAX < 29) ? ZSTD_WINDOWLOG_MAX+1 : 30)
+#define ZSTD_CHAINLOG_MAX_32    29
+#define ZSTD_CHAINLOG_MAX_64    30
+#define ZSTD_CHAINLOG_MAX     ((unsigned)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64))
 #define ZSTD_CHAINLOG_MIN       ZSTD_HASHLOG_MIN
 #define ZSTD_HASHLOG3_MAX       17
 #define ZSTD_SEARCHLOG_MAX     (ZSTD_WINDOWLOG_MAX-1)