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-rw-r--r--lib/ashlti3.c44
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diff --git a/lib/ashlti3.c b/lib/ashlti3.c
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+//===-- ashlti3.c - Implement __ashlti3 -----------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __ashlti3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#if __x86_64
+
+#include "int_lib.h"
+
+// Returns: a << b
+
+// Precondition: 0 <= b < bits_in_tword
+
+ti_int
+__ashlti3(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.low = 0;
+ result.high = input.low << (b - bits_in_dword);
+ }
+ else // 0 <= b < bits_in_dword
+ {
+ if (b == 0)
+ return a;
+ result.low = input.low << b;
+ result.high = (input.high << b) | (input.low >> (bits_in_dword - b));
+ }
+ return result.all;
+}
+
+#endif