1 files changed, 53 insertions, 0 deletions
diff --git a/lib/muldi3.c b/lib/muldi3.c
new file mode 100644
index 000000000..98299e6f0
--- /dev/null
+++ b/lib/muldi3.c
@@ -0,0 +1,53 @@
+//===-- muldi3.c - Implement __muldi3 -------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __muldi3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+// Returns: a * b
+
+static
+di_int
+__muldsi3(su_int a, su_int b)
+{
+    dwords r;
+    const int bits_in_word_2 = (int)(sizeof(si_int) * CHAR_BIT) / 2;
+    const su_int lower_mask = (su_int)~0 >> bits_in_word_2;
+    r.low = (a & lower_mask) * (b & lower_mask);
+    su_int t = r.low >> bits_in_word_2;
+    r.low &= lower_mask;
+    t += (a >> bits_in_word_2) * (b & lower_mask);
+    r.low += (t & lower_mask) << bits_in_word_2;
+    r.high = t >> bits_in_word_2;
+    t = r.low >> bits_in_word_2;
+    r.low &= lower_mask;
+    t += (b >> bits_in_word_2) * (a & lower_mask);
+    r.low += (t & lower_mask) << bits_in_word_2;
+    r.high += t >> bits_in_word_2;
+    r.high += (a >> bits_in_word_2) * (b >> bits_in_word_2);
+    return r.all;
+}
+
+// Returns: a * b
+
+di_int
+__muldi3(di_int a, di_int b)
+{
+    dwords x;
+    x.all = a;
+    dwords y;
+    y.all = b;
+    dwords r;
+    r.all = __muldsi3(x.low, y.low);
+    r.high += x.high * y.low + x.low * y.high;
+    return r.all;
+}