diff --git a/lib/ashrti3.c b/lib/ashrti3.c
new file mode 100644
index 0000000..bfdd2eb
--- /dev/null
+++ b/lib/ashrti3.c
@@ -0,0 +1,45 @@
+//===-- ashrti3.c - Implement __ashrti3 -----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __ashrti3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#if __x86_64
+
+#include "int_lib.h"
+
+// Returns: arithmetic a >> b
+
+// Precondition:  0 <= b < bits_in_tword
+
+ti_int
+__ashrti3(ti_int a, si_int b)
+{
+    const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
+    twords input;
+    twords result;
+    input.all = a;
+    if (b & bits_in_dword)  // bits_in_dword <= b < bits_in_tword
+    {
+        // result.high = input.high < 0 ? -1 : 0
+        result.high = input.high >> (bits_in_dword - 1);
+        result.low = input.high >> (b - bits_in_dword);
+    }
+    else  // 0 <= b < bits_in_dword
+    {
+        if (b == 0)
+            return a;
+        result.high  = input.high >> b;
+        result.low = (input.high << (bits_in_dword - b)) | (input.low >> b);
+    }
+    return result.all;
+}
+
+#endif