projects / mirror_edk2.git / blame
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|---|---|---|
| 3aa8dc6c LQ |
1 | ;------------------------------------------------------------------------------\r |
| 2 | ;\r | |
| 3 | ; Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>\r | |
| 4 | ; This program and the accompanying materials\r | |
| 5 | ; are licensed and made available under the terms and conditions of the BSD License\r | |
| 6 | ; which accompanies this distribution. The full text of the license may be found at\r | |
| 7 | ; http://opensource.org/licenses/bsd-license.php.\r | |
| 8 | ;\r | |
| 9 | ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
| 10 | ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
| 11 | ;\r | |
| 12 | ; Module Name:\r | |
| 13 | ;\r | |
| 14 | ; AsmRdRand.Asm\r | |
| 15 | ;\r | |
| 16 | ; Abstract:\r | |
| 17 | ;\r | |
| 18 | ; Implementation for 16-, and 32- invocations of RDRAND instruction under 32bit platform.\r | |
| 19 | ;\r | |
| 20 | ; Notes:\r | |
| 21 | ;\r | |
| 22 | ; Visual Studio coding practices do not use inline asm since multiple compilers and \r | |
| 23 | ; architectures are supported assembler not recognizing rdrand instruction so using DB's.\r | |
| 24 | ;\r | |
| 25 | ;------------------------------------------------------------------------------\r | |
| 26 | \r | |
| 27 | .586P\r | |
| 28 | .model flat, C\r | |
| 29 | .code\r | |
| 30 | \r | |
| 31 | ;------------------------------------------------------------------------------\r | |
| 32 | ; Generate a 16 bit random number\r | |
| 33 | ; Return TRUE if Rand generated successfully, or FALSE if not\r | |
| 34 | ;\r | |
| 35 | ; BOOLEAN EFIAPI RdRand16Step (UINT16 *Rand); ECX\r | |
| 36 | ;------------------------------------------------------------------------------\r | |
| 37 | RdRand16Step PROC\r | |
| 38 | ; rdrand ax ; generate a 16 bit RN into ax, CF=1 if RN generated ok, otherwise CF=0\r | |
| 39 | db 0fh, 0c7h, 0f0h ; rdrand r16: "0f c7 /6 ModRM:r/m(w)"\r | |
| 40 | jb rn16_ok ; jmp if CF=1\r | |
| 41 | xor eax, eax ; reg=0 if CF=0\r | |
| 42 | ret ; return with failure status\r | |
| 43 | rn16_ok:\r | |
| 44 | mov [ecx], ax\r | |
| 45 | mov eax, 1\r | |
| 46 | ret\r | |
| 47 | RdRand16Step ENDP\r | |
| 48 | \r | |
| 49 | ;------------------------------------------------------------------------------\r | |
| 50 | ; Generate a 32 bit random number\r | |
| 51 | ; Return TRUE if Rand generated successfully, or FALSE if not\r | |
| 52 | ;\r | |
| 53 | ; BOOLEAN EFIAPI RdRand32Step (UINT32 *Rand); ECX\r | |
| 54 | ;------------------------------------------------------------------------------\r | |
| 55 | RdRand32Step PROC\r | |
| 56 | ; rdrand eax ; generate a 32 bit RN into eax, CF=1 if RN generated ok, otherwise CF=0\r | |
| 57 | db 0fh, 0c7h, 0f0h ; rdrand r32: "0f c7 /6 ModRM:r/m(w)"\r | |
| 58 | jb rn32_ok ; jmp if CF=1\r | |
| 59 | xor eax, eax ; reg=0 if CF=0\r | |
| 60 | ret ; return with failure status\r | |
| 61 | rn32_ok:\r | |
| 62 | mov [ecx], eax\r | |
| 63 | mov eax, 1\r | |
| 64 | ret\r | |
| 65 | RdRand32Step ENDP\r | |
| 66 | \r | |
| 67 | END\r |