Provide add and sub for IEEE quad. From GuanHong Liu.

Differential Revision: http://reviews.llvm.org/D2798

llvm-svn: 211312

1 files changed, 27 insertions, 0 deletions

diff --git a/compiler-rt/lib/builtins/subtf3.c b/compiler-rt/lib/builtins/subtf3.c
new file mode 100644
index 00000000000..609b816f41e
--- /dev/null
+++ b/compiler-rt/lib/builtins/subtf3.c
@@ -0,0 +1,27 @@
+//===-- lib/subtf3.c - Quad-precision subtraction -----------------*- C -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements quad-precision soft-float subtraction with the
+// IEEE-754 default rounding (to nearest, ties to even).
+//
+//===----------------------------------------------------------------------===//
+
+#define QUAD_PRECISION
+#include "fp_lib.h"
+
+#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
+COMPILER_RT_ABI fp_t __addtf3(fp_t a, fp_t b);
+
+// Subtraction; flip the sign bit of b and add.
+COMPILER_RT_ABI fp_t
+__subtf3(fp_t a, fp_t b) {
+    return __addtf3(a, fromRep(toRep(b) ^ signBit));
+}
+
+#endif