1 /* ===-- ashrti3.c - Implement __ashrti3 -----------------------------------=== 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 __ashrti3 for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #if __x86_64 16 17 #include "int_lib.h" 18 19 /* Returns: arithmetic a >> b */ 20 21 /* Precondition: 0 <= b < bits_in_tword */ 22 23 ti_int 24 __ashrti3(ti_int a, si_int b) 25 { 26 const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT); 27 twords input; 28 twords result; 29 input.all = a; 30 if (b & bits_in_dword) /* bits_in_dword <= b < bits_in_tword */ 31 { 32 /* result.s.high = input.s.high < 0 ? -1 : 0 */ 33 result.s.high = input.s.high >> (bits_in_dword - 1); 34 result.s.low = input.s.high >> (b - bits_in_dword); 35 } 36 else /* 0 <= b < bits_in_dword */ 37 { 38 if (b == 0) 39 return a; 40 result.s.high = input.s.high >> b; 41 result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b); 42 } 43 return result.all; 44 } 45 46 #endif /* __x86_64 */ 47
