| 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 | |