1#------------------------------------------------------------------------------ ; 2# Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR> 3# This program and the accompanying materials 4# are licensed and made available under the terms and conditions of the BSD License 5# which accompanies this distribution. The full text of the license may be found at 6# http://opensource.org/licenses/bsd-license.php. 7# 8# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 9# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 10# 11# Module Name: 12# 13# RdRand.S 14# 15# Abstract: 16# 17# Generates random number through CPU RdRand instruction under 32-bit platform. 18# 19# Notes: 20# 21#------------------------------------------------------------------------------ 22 23//------------------------------------------------------------------------------ 24// Generates a 16 bit random number through RDRAND instruction. 25// Return TRUE if Rand generated successfully, or FALSE if not. 26// 27// BOOLEAN EFIAPI InternalX86RdRand16 (UINT16 *Rand); 28//------------------------------------------------------------------------------ 29ASM_GLOBAL ASM_PFX(InternalX86RdRand16) 30ASM_PFX(InternalX86RdRand16): 31 .byte 0x0f, 0xc7, 0xf0 // rdrand r16: "0f c7 /6 ModRM:r/m(w)" 32 jc rn16_ok // jmp if CF=1 33 xor %eax, %eax // reg=0 if CF=0 34 ret // return with failure status 35rn16_ok: 36 mov 0x4(%esp), %edx 37 mov %ax, (%edx) 38 mov $0x1, %eax 39 ret 40 41//------------------------------------------------------------------------------ 42// Generates a 32 bit random number through RDRAND instruction. 43// Return TRUE if Rand generated successfully, or FALSE if not. 44// 45// BOOLEAN EFIAPI InternalX86RdRand32 (UINT32 *Rand); 46//------------------------------------------------------------------------------ 47ASM_GLOBAL ASM_PFX(InternalX86RdRand32) 48ASM_PFX(InternalX86RdRand32): 49 .byte 0x0f, 0xc7, 0xf0 // rdrand r32: "0f c7 /6 ModRM:r/m(w)" 50 jc rn32_ok // jmp if CF=1 51 xor %eax, %eax // reg=0 if CF=0 52 ret // return with failure status 53rn32_ok: 54 mov 0x4(%esp), %edx 55 mov %eax, (%edx) 56 mov $0x1, %eax 57 ret 58 59//------------------------------------------------------------------------------ 60// Generates a 64 bit random number through RDRAND instruction. 61// Return TRUE if Rand generated successfully, or FALSE if not. 62// 63// BOOLEAN EFIAPI InternalX86RdRand64 (UINT64 *Rand); 64//------------------------------------------------------------------------------ 65ASM_GLOBAL ASM_PFX(InternalX86RdRand64) 66ASM_PFX(InternalX86RdRand64): 67 .byte 0x0f, 0xc7, 0xf0 // rdrand r32: "0f c7 /6 ModRM:r/m(w)" 68 jnc rn64_ret // jmp if CF=0 69 mov 0x4(%esp), %edx 70 mov %eax, (%edx) 71 72 .byte 0x0f, 0xc7, 0xf0 // generate another 32 bit RN 73 jnc rn64_ret // jmp if CF=0 74 mov %eax, 0x4(%edx) 75 76 mov $0x1, %eax 77 ret 78rn64_ret: 79 xor %eax, %eax 80 ret // return with failure status 81