Move original compiler-rt functions (libgcc replacement) to lib/builtins directory

llvm-svn: 201393

1 files changed, 47 insertions, 0 deletions

diff --git a/compiler-rt/lib/builtins/fixunsdfti.c b/compiler-rt/lib/builtins/fixunsdfti.c
new file mode 100644
index 00000000000..fb0336f6908
--- /dev/null
+++ b/compiler-rt/lib/builtins/fixunsdfti.c
@@ -0,0 +1,47 @@
+/* ===-- fixunsdfti.c - Implement __fixunsdfti -----------------------------===
+ *
+ *                     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 __fixunsdfti for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+#if __x86_64
+
+/* Returns: convert a to a unsigned long long, rounding toward zero.
+ *          Negative values all become zero.
+ */
+
+/* Assumption: double is a IEEE 64 bit floating point type 
+ *             tu_int is a 64 bit integral type
+ *             value in double is representable in tu_int or is negative 
+ *                 (no range checking performed)
+ */
+
+/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
+
+tu_int
+__fixunsdfti(double a)
+{
+    double_bits fb;
+    fb.f = a;
+    int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
+    if (e < 0 || (fb.u.s.high & 0x80000000))
+        return 0;
+    tu_int r = 0x0010000000000000uLL | (fb.u.all & 0x000FFFFFFFFFFFFFuLL);
+    if (e > 52)
+        r <<= (e - 52);
+    else
+        r >>= (52 - e);
+    return r;
+}
+
+#endif