1 files changed, 46 insertions, 0 deletions
diff --git a/compiler-rt/lib/builtins/fixxfti.c b/compiler-rt/lib/builtins/fixxfti.c
new file mode 100644
index 000000000000..90e03116e7ca
--- /dev/null
+++ b/compiler-rt/lib/builtins/fixxfti.c
@@ -0,0 +1,46 @@
+//===-- fixxfti.c - Implement __fixxfti -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __fixxfti for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+#ifdef CRT_HAS_128BIT
+
+// Returns: convert a to a signed long long, rounding toward zero.
+
+// Assumption: long double is an intel 80 bit floating point type padded with 6
+// bytes ti_int is a 128 bit integral type value in long double is representable
+// in ti_int
+
+// 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
+
+COMPILER_RT_ABI ti_int __fixxfti(long double a) {
+  const ti_int ti_max = (ti_int)((~(tu_int)0) / 2);
+  const ti_int ti_min = -ti_max - 1;
+  long_double_bits fb;
+  fb.f = a;
+  int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
+  if (e < 0)
+    return 0;
+  ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
+  ti_int r = fb.u.low.all;
+  if ((unsigned)e >= sizeof(ti_int) * CHAR_BIT)
+    return a > 0 ? ti_max : ti_min;
+  if (e > 63)
+    r <<= (e - 63);
+  else
+    r >>= (63 - e);
+  return (r ^ s) - s;
+}
+
+#endif // CRT_HAS_128BIT