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1 | /** @file\r | |
2 | 64-bit Math Worker Function.\r | |
3 | The 32-bit versions of C compiler generate calls to library routines\r | |
4 | to handle 64-bit math. These functions use non-standard calling conventions.\r | |
5 | \r | |
6 | Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>\r | |
7 | SPDX-License-Identifier: BSD-2-Clause-Patent\r | |
8 | \r | |
9 | **/\r | |
10 | \r | |
11 | /*\r | |
12 | * Shifts a 64-bit unsigned value right by a certain number of bits.\r | |
13 | */\r | |
14 | __declspec(naked) void __cdecl\r | |
15 | _aullshr (\r | |
16 | void\r | |
17 | )\r | |
18 | {\r | |
19 | _asm {\r | |
20 | ;\r | |
21 | ; Checking: Only handle 64bit shifting or more\r | |
22 | ;\r | |
23 | cmp cl, 64\r | |
24 | jae _Exit\r | |
25 | \r | |
26 | ;\r | |
27 | ; Handle shifting between 0 and 31 bits\r | |
28 | ;\r | |
29 | cmp cl, 32\r | |
30 | jae More32\r | |
31 | shrd eax, edx, cl\r | |
32 | shr edx, cl\r | |
33 | ret\r | |
34 | \r | |
35 | ;\r | |
36 | ; Handle shifting of 32-63 bits\r | |
37 | ;\r | |
38 | More32:\r | |
39 | mov eax, edx\r | |
40 | xor edx, edx\r | |
41 | and cl, 31\r | |
42 | shr eax, cl\r | |
43 | ret\r | |
44 | \r | |
45 | ;\r | |
46 | ; Invalid number (less then 32bits), return 0\r | |
47 | ;\r | |
48 | \r | |
49 | _Exit:\r | |
50 | xor eax, eax\r | |
51 | xor edx, edx\r | |
52 | ret\r | |
53 | }\r | |
54 | }\r |