1;------------------------------------------------------------------------------ 2; 3; Copyright (c) 2015 - 2016, 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 InternalX86RdRand16 (UINT16 *Rand); 31;------------------------------------------------------------------------------ 32InternalX86RdRand16 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 39rn16_ok: 40 mov [rcx], ax 41 mov rax, 1 42 ret 43InternalX86RdRand16 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 InternalX86RdRand32 (UINT32 *Rand); 50;------------------------------------------------------------------------------ 51InternalX86RdRand32 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 58rn32_ok: 59 mov [rcx], eax 60 mov rax, 1 61 ret 62InternalX86RdRand32 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 InternalX86RdRand64 (UINT64 *Random); 69;------------------------------------------------------------------------------ 70InternalX86RdRand64 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 77rn64_ok: 78 mov [rcx], rax 79 mov rax, 1 80 ret 81InternalX86RdRand64 ENDP 82 83 END 84