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1 | /** @file\r |
2 | InterlockedCompareExchange16 function\r | |
3 | \r | |
4cee954e | 4 | Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>\r |
09f08c92 HT |
5 | Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>\r |
6 | This program and the accompanying materials\r | |
7 | are licensed and made available under the terms and conditions of the BSD License\r | |
8 | which accompanies this distribution. The full text of the license may be found at\r | |
9 | http://opensource.org/licenses/bsd-license.php.\r | |
10 | \r | |
11 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
12 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
13 | \r | |
14 | **/\r | |
15 | \r | |
16 | \r | |
17 | \r | |
18 | \r | |
19 | /**\r | |
20 | Performs an atomic compare exchange operation on a 16-bit unsigned integer.\r | |
21 | \r | |
22 | Performs an atomic compare exchange operation on the 16-bit unsigned integer\r | |
23 | specified by Value. If Value is equal to CompareValue, then Value is set to\r | |
24 | ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r | |
25 | then Value is returned. The compare exchange operation must be performed using\r | |
26 | MP safe mechanisms.\r | |
27 | \r | |
28 | @param Value A pointer to the 16-bit value for the compare exchange\r | |
29 | operation.\r | |
30 | @param CompareValue 16-bit value used in compare operation.\r | |
31 | @param ExchangeValue 16-bit value used in exchange operation.\r | |
32 | \r | |
33 | @return The original *Value before exchange.\r | |
34 | \r | |
35 | **/\r | |
36 | UINT16\r | |
37 | EFIAPI\r | |
38 | InternalSyncCompareExchange16 (\r | |
4cee954e | 39 | IN volatile UINT16 *Value,\r |
09f08c92 HT |
40 | IN UINT16 CompareValue,\r |
41 | IN UINT16 ExchangeValue\r | |
42 | )\r | |
43 | {\r | |
44 | _asm {\r | |
45 | mov ecx, Value\r | |
46 | mov ax, CompareValue\r | |
47 | mov dx, ExchangeValue\r | |
48 | lock cmpxchg [ecx], dx\r | |
49 | }\r | |
50 | }\r | |
51 | \r |