projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| 97f98500 HT |
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 | |
| 2ac68e8b | 6 | Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>\r |
| 2009f6b4 | 7 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
| 97f98500 HT |
8 | \r |
| 9 | **/\r | |
| 10 | \r | |
| 11 | \r | |
| 12 | /*\r | |
| 13 | * Shifts a 64-bit unsigned value right by a certain number of bits.\r | |
| 14 | */\r | |
| 15 | __declspec(naked) void __cdecl _aullshr (void)\r | |
| 16 | {\r | |
| 17 | _asm {\r | |
| 18 | ;\r | |
| 19 | ; Checking: Only handle 64bit shifting or more\r | |
| 20 | ;\r | |
| 21 | cmp cl, 64\r | |
| 22 | jae _Exit\r | |
| 23 | \r | |
| 24 | ;\r | |
| 25 | ; Handle shifting between 0 and 31 bits\r | |
| 26 | ;\r | |
| 27 | cmp cl, 32\r | |
| 28 | jae More32\r | |
| 29 | shrd eax, edx, cl\r | |
| 30 | shr edx, cl\r | |
| 31 | ret\r | |
| 32 | \r | |
| 33 | ;\r | |
| 34 | ; Handle shifting of 32-63 bits\r | |
| 35 | ;\r | |
| 36 | More32:\r | |
| 37 | mov eax, edx\r | |
| 38 | xor edx, edx\r | |
| 39 | and cl, 31\r | |
| 40 | shr eax, cl\r | |
| 41 | ret\r | |
| 42 | \r | |
| 43 | ;\r | |
| 44 | ; Invalid number (less then 32bits), return 0\r | |
| 45 | ;\r | |
| 46 | _Exit:\r | |
| 47 | xor eax, eax\r | |
| 48 | xor edx, edx\r | |
| 49 | ret\r | |
| 50 | }\r | |
| 51 | }\r |