1 files changed, 49 insertions, 0 deletions
diff --git a/lib/fixunsxfti.c b/lib/fixunsxfti.c
new file mode 100644
index 000000000000..d0bd512c4d41
--- /dev/null
+++ b/lib/fixunsxfti.c
@@ -0,0 +1,49 @@
+/* ===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===
+ *
+ *      	       The LLVM Compiler Infrastructure
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __fixunsxfti for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#if __x86_64
+
+#include "int_lib.h"
+
+/* Returns: convert a to a unsigned long long, rounding toward zero.
+ *          Negative values all become zero.
+ */
+
+/* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
+ *             tu_int is a 64 bit integral type
+ *             value in long double is representable in tu_int or is negative 
+ *                 (no range checking performed)
+ */
+
+/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
+ * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
+ */
+
+tu_int
+__fixunsxfti(long double a)
+{
+    long_double_bits fb;
+    fb.f = a;
+    int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
+    if (e < 0 || (fb.u.high.s.low & 0x00008000))
+        return 0;
+    tu_int r = fb.u.low.all;
+    if (e > 63)
+        r <<= (e - 63);
+    else
+        r >>= (63 - e);
+    return r;
+}
+
+#endif