1 files changed, 26 insertions, 0 deletions
diff --git a/lib/builtins/subdf3.c b/lib/builtins/subdf3.c
new file mode 100644
index 000000000000..089e062415b7
--- /dev/null
+++ b/lib/builtins/subdf3.c
@@ -0,0 +1,26 @@
+//===-- lib/adddf3.c - Double-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 double-precision soft-float subtraction with the
+// IEEE-754 default rounding (to nearest, ties to even).
+//
+//===----------------------------------------------------------------------===//
+
+#define DOUBLE_PRECISION
+#include "fp_lib.h"
+
+ARM_EABI_FNALIAS(dsub, subdf3)
+
+// Subtraction; flip the sign bit of b and add.
+COMPILER_RT_ABI fp_t
+__subdf3(fp_t a, fp_t b) {
+    return __adddf3(a, fromRep(toRep(b) ^ signBit));
+}
+
+/* FIXME: rsub for ARM EABI */