diff --git a/libc/bionic/mbrtoc16.cpp b/libc/bionic/mbrtoc16.cpp
new file mode 100644
index 0000000..6878a11
--- /dev/null
+++ b/libc/bionic/mbrtoc16.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <uchar.h>
+#include <wchar.h>
+
+#include "private/bionic_mbstate.h"
+
+static inline bool mbspartialc16(const mbstate_t* state) {
+  return mbstate_get_byte(state, 3) != 0;
+}
+
+static size_t begin_surrogate(char32_t c32, char16_t* pc16,
+                              size_t nconv, mbstate_t* state) {
+  c32 -= 0x10000;
+  char16_t trail = (c32 & 0x3ff) | 0xdc00;
+
+  mbstate_set_byte(state, 0, trail & 0x00ff);
+  mbstate_set_byte(state, 1, (trail & 0xff00) >> 8);
+  mbstate_set_byte(state, 3, nconv & 0xff);
+
+  *pc16 = ((c32 & 0xffc00) >> 10) | 0xd800;
+  // Defined by POSIX as return value for first surrogate character.
+  return static_cast<size_t>(-3);
+}
+
+static size_t finish_surrogate(char16_t* pc16, mbstate_t* state) {
+  char16_t trail = mbstate_get_byte(state, 1) << 8 |
+                   mbstate_get_byte(state, 0);
+  *pc16 = trail;
+  return reset_and_return(mbstate_get_byte(state, 3), state);
+}
+
+size_t mbrtoc16(char16_t* pc16, const char* s, size_t n, mbstate_t* ps) {
+  static mbstate_t __private_state;
+  mbstate_t* state = (ps == NULL) ? &__private_state : ps;
+
+  char16_t __private_pc16;
+  if (pc16 == NULL) {
+    pc16 = &__private_pc16;
+  }
+
+  if (mbspartialc16(state)) {
+    return finish_surrogate(pc16, state);
+  }
+
+  char32_t c32;
+  size_t nconv = mbrtoc32(&c32, s, n, state);
+  if (__MB_IS_ERR(nconv)) {
+    return nconv;
+  } else if (nconv == 0) {
+    return reset_and_return(nconv, state);
+  } else if (c32 > 0x10ffff) {
+    // Input cannot be encoded as UTF-16.
+    return reset_and_return_illegal(EILSEQ, state);
+  } else if (c32 < 0x10000) {
+    *pc16 = static_cast<char16_t>(c32);
+    return reset_and_return(nconv, state);
+  } else {
+    return begin_surrogate(c32, pc16, nconv, state);
+  }
+}