| //===-- ashrti3.c - Implement __ashrti3 -----------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements __ashrti3 for the compiler_rt library. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #if __x86_64 |
| |
| #include "int_lib.h" |
| |
| // Returns: arithmetic a >> b |
| |
| // Precondition: 0 <= b < bits_in_tword |
| |
| ti_int |
| __ashrti3(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.high = input.high < 0 ? -1 : 0 |
| result.high = input.high >> (bits_in_dword - 1); |
| result.low = input.high >> (b - bits_in_dword); |
| } |
| else // 0 <= b < bits_in_dword |
| { |
| if (b == 0) |
| return a; |
| result.high = input.high >> b; |
| result.low = (input.high << (bits_in_dword - b)) | (input.low >> b); |
| } |
| return result.all; |
| } |
| |
| #endif |