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1;------------------------------------------------------------------------------\r
2;\r
9ec9a7a5 3; Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>\r
9344f092 4; SPDX-License-Identifier: BSD-2-Clause-Patent\r
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5;\r
6; Module Name:\r
7;\r
8; RdRand.nasm\r
9;\r
10; Abstract:\r
11;\r
12; Generates random number through CPU RdRand instruction under 32-bit platform.\r
13;\r
14; Notes:\r
15;\r
16;------------------------------------------------------------------------------\r
17\r
18SECTION .text\r
19\r
20;------------------------------------------------------------------------------\r
21; Generates a 16 bit random number through RDRAND instruction.\r
22; Return TRUE if Rand generated successfully, or FALSE if not.\r
23;\r
9ec9a7a5 24; BOOLEAN EFIAPI InternalX86RdRand16 (UINT16 *Rand);\r
55745c24 25;------------------------------------------------------------------------------\r
9ec9a7a5
QL
26global ASM_PFX(InternalX86RdRand16)\r
27ASM_PFX(InternalX86RdRand16):\r
55745c24
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28 ; rdrand ax ; generate a 16 bit RN into ax\r
29 ; CF=1 if RN generated ok, otherwise CF=0\r
30 db 0xf, 0xc7, 0xf0 ; rdrand r16: "0f c7 /6 ModRM:r/m(w)"\r
31 jc rn16_ok ; jmp if CF=1\r
32 xor eax, eax ; reg=0 if CF=0\r
33 ret ; return with failure status\r
34rn16_ok:\r
35 mov edx, dword [esp + 4]\r
36 mov [edx], ax\r
37 mov eax, 1\r
38 ret\r
39\r
40;------------------------------------------------------------------------------\r
41; Generates a 32 bit random number through RDRAND instruction.\r
42; Return TRUE if Rand generated successfully, or FALSE if not.\r
43;\r
9ec9a7a5 44; BOOLEAN EFIAPI InternalX86RdRand32 (UINT32 *Rand);\r
55745c24 45;------------------------------------------------------------------------------\r
9ec9a7a5
QL
46global ASM_PFX(InternalX86RdRand32)\r
47ASM_PFX(InternalX86RdRand32):\r
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48 ; rdrand eax ; generate a 32 bit RN into eax\r
49 ; CF=1 if RN generated ok, otherwise CF=0\r
50 db 0xf, 0xc7, 0xf0 ; rdrand r32: "0f c7 /6 ModRM:r/m(w)"\r
51 jc rn32_ok ; jmp if CF=1\r
52 xor eax, eax ; reg=0 if CF=0\r
53 ret ; return with failure status\r
54rn32_ok:\r
55 mov edx, dword [esp + 4]\r
56 mov [edx], eax\r
57 mov eax, 1\r
58 ret\r
59\r
60;------------------------------------------------------------------------------\r
61; Generates a 64 bit random number through RDRAND instruction.\r
62; Return TRUE if Rand generated successfully, or FALSE if not.\r
63;\r
9ec9a7a5 64; BOOLEAN EFIAPI InternalX86RdRand64 (UINT64 *Rand);\r
55745c24 65;------------------------------------------------------------------------------\r
9ec9a7a5
QL
66global ASM_PFX(InternalX86RdRand64)\r
67ASM_PFX(InternalX86RdRand64):\r
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68 ; rdrand eax ; generate a 32 bit RN into eax\r
69 ; CF=1 if RN generated ok, otherwise CF=0\r
70 db 0xf, 0xc7, 0xf0 ; rdrand r32: "0f c7 /6 ModRM:r/m(w)"\r
71 jnc rn64_ret ; jmp if CF=0\r
72 mov edx, dword [esp + 4]\r
73 mov [edx], eax\r
74\r
75 db 0xf, 0xc7, 0xf0 ; generate another 32 bit RN\r
76 jnc rn64_ret ; jmp if CF=0\r
77 mov [edx + 4], eax\r
78\r
79 mov eax, 1\r
80 ret\r
81rn64_ret:\r
82 xor eax, eax\r
83 ret ; return with failure status\r
84\r