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

llvm-svn: 201393

1 files changed, 46 insertions, 0 deletions

diff --git a/compiler-rt/lib/builtins/ashrti3.c b/compiler-rt/lib/builtins/ashrti3.c
new file mode 100644
index 00000000000..ed43641c7ef
--- /dev/null
+++ b/compiler-rt/lib/builtins/ashrti3.c
@@ -0,0 +1,46 @@
+/* ===-- ashrti3.c - Implement __ashrti3 -----------------------------------===
+ *
+ *                     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 __ashrti3 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+#if __x86_64
+
+/* Returns: arithmetic a >> b */
+
+/* Precondition:  0 <= b < bits_in_tword */
+
+ti_int
+__ashrti3(ti_int a, si_int b)
+{
+    const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
+    twords input;
+    twords result;
+    input.all = a;
+    if (b & bits_in_dword)  /* bits_in_dword <= b < bits_in_tword */
+    {
+        /* result.s.high = input.s.high < 0 ? -1 : 0 */
+        result.s.high = input.s.high >> (bits_in_dword - 1);
+        result.s.low = input.s.high >> (b - bits_in_dword);
+    }
+    else  /* 0 <= b < bits_in_dword */
+    {
+        if (b == 0)
+            return a;
+        result.s.high  = input.s.high >> b;
+        result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b);
+    }
+    return result.all;
+}
+
+#endif /* __x86_64 */