1 //===-- ashrdi3.c - Implement __ashrdi3 -----------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements __ashrdi3 for the compiler_rt library. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "int_lib.h" 14 15 // Returns: arithmetic a >> b 16 17 // Precondition: 0 <= b < bits_in_dword 18 19 COMPILER_RT_ABI di_int __ashrdi3(di_int a, int b) { 20 const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT); 21 dwords input; 22 dwords result; 23 input.all = a; 24 if (b & bits_in_word) /* bits_in_word <= b < bits_in_dword */ { 25 // result.s.high = input.s.high < 0 ? -1 : 0 26 result.s.high = input.s.high >> (bits_in_word - 1); 27 result.s.low = input.s.high >> (b - bits_in_word); 28 } else /* 0 <= b < bits_in_word */ { 29 if (b == 0) 30 return a; 31 result.s.high = input.s.high >> b; 32 result.s.low = 33 ((su_int)input.s.high << (bits_in_word - b)) | (input.s.low >> b); 34 } 35 return result.all; 36 } 37 38 #if defined(__ARM_EABI__) 39 COMPILER_RT_ALIAS(__ashrdi3, __aeabi_lasr) 40 #endif 41