1 #------------------------------------------------------------------------------ ; 2 # Copyright (c) 2015, 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 AsmRdRand16 (UINT16 *Rand); 28 //------------------------------------------------------------------------------ 29 ASM_GLOBAL ASM_PFX(AsmRdRand16) 30 ASM_PFX(AsmRdRand16): 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 35 rn16_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 AsmRdRand32 (UINT32 *Rand); 46 //------------------------------------------------------------------------------ 47 ASM_GLOBAL ASM_PFX(AsmRdRand32) 48 ASM_PFX(AsmRdRand32): 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 53 rn32_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 AsmRdRand64 (UINT64 *Rand); 64 //------------------------------------------------------------------------------ 65 ASM_GLOBAL ASM_PFX(AsmRdRand64) 66 ASM_PFX(AsmRdRand64): 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 78 rn64_ret: 79 xor %eax, %eax 80 ret // return with failure status 81
