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      1 /* ===-- lshrti3.c - Implement __lshrti3 -----------------------------------===
      2  *
      3  *                     The LLVM Compiler Infrastructure
      4  *
      5  * This file is dual licensed under the MIT and the University of Illinois Open
      6  * Source Licenses. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  *
     10  * This file implements __lshrti3 for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #include "int_lib.h"
     16 
     17 #ifdef CRT_HAS_128BIT
     18 
     19 /* Returns: logical a >> b */
     20 
     21 /* Precondition:  0 <= b < bits_in_tword */
     22 
     23 COMPILER_RT_ABI ti_int
     24 __lshrti3(ti_int a, si_int b)
     25 {
     26     const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
     27     utwords input;
     28     utwords result;
     29     input.all = a;
     30     if (b & bits_in_dword)  /* bits_in_dword <= b < bits_in_tword */
     31     {
     32         result.s.high = 0;
     33         result.s.low = input.s.high >> (b - bits_in_dword);
     34     }
     35     else  /* 0 <= b < bits_in_dword */
     36     {
     37         if (b == 0)
     38             return a;
     39         result.s.high  = input.s.high >> b;
     40         result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b);
     41     }
     42     return result.all;
     43 }
     44 
     45 #endif /* CRT_HAS_128BIT */
     46