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      1 /* ====-- ashldi3.c - Implement __ashldi3 -----------------------------------===
      2  *
      3  *                     The LLVM Compiler Infrastructure
      4  *
      5  * This file is distributed under the University of Illinois Open Source
      6  * License. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  *
     10  * This file implements __ashldi3 for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #include "int_lib.h"
     16 
     17 /* Returns: a << b */
     18 
     19 /* Precondition:  0 <= b < bits_in_dword */
     20 
     21 di_int
     22 __ashldi3(di_int a, si_int b)
     23 {
     24     const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
     25     dwords input;
     26     dwords result;
     27     input.all = a;
     28     if (b & bits_in_word)  /* bits_in_word <= b < bits_in_dword */
     29     {
     30         result.s.low = 0;
     31         result.s.high = input.s.low << (b - bits_in_word);
     32     }
     33     else  /* 0 <= b < bits_in_word */
     34     {
     35         if (b == 0)
     36             return a;
     37         result.s.low  = input.s.low << b;
     38         result.s.high = (input.s.high << b) | (input.s.low >> (bits_in_word - b));
     39     }
     40     return result.all;
     41 }
     42