1 files changed, 2 insertions, 3 deletions
diff --git a/enc/utf_16be.c b/enc/utf_16be.c
index d6e2c953b7..1e33c2ec7d 100644
--- a/enc/utf_16be.c
+++ b/enc/utf_16be.c
@@ -108,9 +108,8 @@ utf16be_mbc_to_code(const UChar* p, const UChar* end ARG_UNUSED,
   OnigCodePoint code;
 
   if (UTF16_IS_SURROGATE_FIRST(*p)) {
-    code = ((((p[0] - 0xd8) << 2) + ((p[1] & 0xc0) >> 6) + 1) << 16)
-         + ((((p[1] & 0x3f) << 2) + (p[2] - 0xdc)) << 8)
-         + p[3];
+    code = ((((p[0] << 8) + p[1]) & 0x03ff) << 10)
+         + (((p[2] << 8) + p[3]) & 0x03ff) + 0x10000;
   }
   else {
     code = p[0] * 256 + p[1];