vendor/compiler-rt/compiler-rt-r224034

1 files changed, 45 insertions, 0 deletions

diff --git a/lib/builtins/lshrti3.c b/lib/builtins/lshrti3.c
new file mode 100644
index 000000000000..e4170ff84a5a
--- /dev/null
+++ b/lib/builtins/lshrti3.c
@@ -0,0 +1,45 @@
+/* ===-- lshrti3.c - Implement __lshrti3 -----------------------------------===
+ *
+ *                     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 __lshrti3 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+#ifdef CRT_HAS_128BIT
+
+/* Returns: logical a >> b */
+
+/* Precondition:  0 <= b < bits_in_tword */
+
+COMPILER_RT_ABI ti_int
+__lshrti3(ti_int a, si_int b)
+{
+    const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
+    utwords input;
+    utwords result;
+    input.all = a;
+    if (b & bits_in_dword)  /* bits_in_dword <= b < bits_in_tword */
+    {
+        result.s.high = 0;
+        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 /* CRT_HAS_128BIT */