bitscan add undef check

2020-03-05 11:52:15 -08:00
parent bc0e10ae78
commit a75e5f2ffc
3 changed files with 6 additions and 12 deletions
@@ -298,8 +298,7 @@ MEM_STATIC U32 ZSTD_highbit32(U32 val)   /* compress, dictBuilder, decodeCorpus
    {
 #   if defined(_MSC_VER)   /* Visual */
        unsigned long r=0;
-        _BitScanReverse(&r, val);
-        return (unsigned)r;
+        _BitScanReverse(&r, val) ? (unsigned)r : 0;
 #   elif defined(__GNUC__) && (__GNUC__ >= 3)   /* GCC Intrinsic */
        return __builtin_clz (val) ^ 31;
 #   elif defined(__ICCARM__)    /* IAR Intrinsic */