Initial import of compiler-rt.
-
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@74292 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/mulvti3.c b/lib/mulvti3.c
new file mode 100644
index 0000000..82efe8c
--- /dev/null
+++ b/lib/mulvti3.c
@@ -0,0 +1,60 @@
+//===-- mulvti3.c - Implement __mulvti3 -----------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __mulvti3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#if __x86_64
+
+#include "int_lib.h"
+#include <stdlib.h>
+
+// Returns: a * b
+
+// Effects: aborts if a * b overflows
+
+ti_int
+__mulvti3(ti_int a, ti_int b)
+{
+ const int N = (int)(sizeof(ti_int) * CHAR_BIT);
+ const ti_int MIN = (ti_int)1 << (N-1);
+ const ti_int MAX = ~MIN;
+ if (a == MIN)
+ {
+ if (b == 0 || b == 1)
+ return a * b;
+ abort();
+ }
+ if (b == MIN)
+ {
+ if (a == 0 || a == 1)
+ return a * b;
+ abort();
+ }
+ ti_int sa = a >> (N - 1);
+ ti_int abs_a = (a ^ sa) - sa;
+ ti_int sb = b >> (N - 1);
+ ti_int abs_b = (b ^ sb) - sb;
+ if (abs_a < 2 || abs_b < 2)
+ return a * b;
+ if (sa == sb)
+ {
+ if (abs_a > MAX / abs_b)
+ abort();
+ }
+ else
+ {
+ if (abs_a > MIN / -abs_b)
+ abort();
+ }
+ return a * b;
+}
+
+#endif