1 ;------------------------------------------------------------------------------ 2 ; 3 ; Copyright (c) 2015, Intel Corporation. All rights reserved.<BR> 4 ; This program and the accompanying materials 5 ; are licensed and made available under the terms and conditions of the BSD License 6 ; which accompanies this distribution. The full text of the license may be found at 7 ; http://opensource.org/licenses/bsd-license.php. 8 ; 9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 ; 12 ; Module Name: 13 ; 14 ; RdRand.asm 15 ; 16 ; Abstract: 17 ; 18 ; Generates random number through CPU RdRand instruction under 32-bit platform. 19 ; 20 ; Notes: 21 ; 22 ;------------------------------------------------------------------------------ 23 24 .686P 25 .model flat, C 26 27 .code 28 29 ;------------------------------------------------------------------------------ 30 ; Generates a 16 bit random number through RDRAND instruction. 31 ; Return TRUE if Rand generated successfully, or FALSE if not. 32 ; 33 ; BOOLEAN EFIAPI AsmRdRand16 (UINT16 *Rand); 34 ;------------------------------------------------------------------------------ 35 AsmRdRand16 PROC 36 ; rdrand ax ; generate a 16 bit RN into ax 37 ; CF=1 if RN generated ok, otherwise CF=0 38 db 0fh, 0c7h, 0f0h ; rdrand r16: "0f c7 /6 ModRM:r/m(w)" 39 jc rn16_ok ; jmp if CF=1 40 xor eax, eax ; reg=0 if CF=0 41 ret ; return with failure status 42 rn16_ok: 43 mov edx, dword ptr [esp + 4] 44 mov [edx], ax 45 mov eax, 1 46 ret 47 AsmRdRand16 ENDP 48 49 ;------------------------------------------------------------------------------ 50 ; Generates a 32 bit random number through RDRAND instruction. 51 ; Return TRUE if Rand generated successfully, or FALSE if not. 52 ; 53 ; BOOLEAN EFIAPI AsmRdRand32 (UINT32 *Rand); 54 ;------------------------------------------------------------------------------ 55 AsmRdRand32 PROC 56 ; rdrand eax ; generate a 32 bit RN into eax 57 ; CF=1 if RN generated ok, otherwise CF=0 58 db 0fh, 0c7h, 0f0h ; rdrand r32: "0f c7 /6 ModRM:r/m(w)" 59 jc rn32_ok ; jmp if CF=1 60 xor eax, eax ; reg=0 if CF=0 61 ret ; return with failure status 62 rn32_ok: 63 mov edx, dword ptr [esp + 4] 64 mov [edx], eax 65 mov eax, 1 66 ret 67 AsmRdRand32 ENDP 68 69 ;------------------------------------------------------------------------------ 70 ; Generates a 64 bit random number through RDRAND instruction. 71 ; Return TRUE if Rand generated successfully, or FALSE if not. 72 ; 73 ; BOOLEAN EFIAPI AsmRdRand64 (UINT64 *Rand); 74 ;------------------------------------------------------------------------------ 75 AsmRdRand64 PROC 76 ; rdrand eax ; generate a 32 bit RN into eax 77 ; CF=1 if RN generated ok, otherwise CF=0 78 db 0fh, 0c7h, 0f0h ; rdrand r32: "0f c7 /6 ModRM:r/m(w)" 79 jnc rn64_ret ; jmp if CF=0 80 mov edx, dword ptr [esp + 4] 81 mov [edx], eax 82 83 db 0fh, 0c7h, 0f0h ; generate another 32 bit RN 84 jnc rn64_ret ; jmp if CF=0 85 mov [edx + 4], eax 86 87 mov eax, 1 88 ret 89 rn64_ret: 90 xor eax, eax 91 ret ; return with failure status 92 AsmRdRand64 ENDP 93 94 END 95
