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 64-bit platform. 19 ; 20 ; Notes: 21 ; 22 ;------------------------------------------------------------------------------ 23 24 .code 25 26 ;------------------------------------------------------------------------------ 27 ; Generates a 16 bit random number through RDRAND instruction. 28 ; Return TRUE if Rand generated successfully, or FALSE if not. 29 ; 30 ; BOOLEAN EFIAPI AsmRdRand16 (UINT16 *Rand); 31 ;------------------------------------------------------------------------------ 32 AsmRdRand16 PROC 33 ; rdrand ax ; generate a 16 bit RN into eax, 34 ; CF=1 if RN generated ok, otherwise CF=0 35 db 0fh, 0c7h, 0f0h ; rdrand r16: "0f c7 /6 ModRM:r/m(w)" 36 jc rn16_ok ; jmp if CF=1 37 xor rax, rax ; reg=0 if CF=0 38 ret ; return with failure status 39 rn16_ok: 40 mov [rcx], ax 41 mov rax, 1 42 ret 43 AsmRdRand16 ENDP 44 45 ;------------------------------------------------------------------------------ 46 ; Generates a 32 bit random number through RDRAND instruction. 47 ; Return TRUE if Rand generated successfully, or FALSE if not. 48 ; 49 ; BOOLEAN EFIAPI AsmRdRand32 (UINT32 *Rand); 50 ;------------------------------------------------------------------------------ 51 AsmRdRand32 PROC 52 ; rdrand eax ; generate a 32 bit RN into eax, 53 ; CF=1 if RN generated ok, otherwise CF=0 54 db 0fh, 0c7h, 0f0h ; rdrand r32: "0f c7 /6 ModRM:r/m(w)" 55 jc rn32_ok ; jmp if CF=1 56 xor rax, rax ; reg=0 if CF=0 57 ret ; return with failure status 58 rn32_ok: 59 mov [rcx], eax 60 mov rax, 1 61 ret 62 AsmRdRand32 ENDP 63 64 ;------------------------------------------------------------------------------ 65 ; Generates a 64 bit random number through one RDRAND instruction. 66 ; Return TRUE if Rand generated successfully, or FALSE if not. 67 ; 68 ; BOOLEAN EFIAPI AsmRdRand64 (UINT64 *Random); 69 ;------------------------------------------------------------------------------ 70 AsmRdRand64 PROC 71 ; rdrand rax ; generate a 64 bit RN into rax, 72 ; CF=1 if RN generated ok, otherwise CF=0 73 db 048h, 0fh, 0c7h, 0f0h ; rdrand r64: "REX.W + 0f c7 /6 ModRM:r/m(w)" 74 jc rn64_ok ; jmp if CF=1 75 xor rax, rax ; reg=0 if CF=0 76 ret ; return with failure status 77 rn64_ok: 78 mov [rcx], rax 79 mov rax, 1 80 ret 81 AsmRdRand64 ENDP 82 83 END 84
