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55745c24 JJ |
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 |
55745c24 JJ |
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 | |
18 | SECTION .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 |
26 | global ASM_PFX(InternalX86RdRand16)\r |
27 | ASM_PFX(InternalX86RdRand16):\r | |
55745c24 JJ |
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 | |
34 | rn16_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 |
46 | global ASM_PFX(InternalX86RdRand32)\r |
47 | ASM_PFX(InternalX86RdRand32):\r | |
55745c24 JJ |
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 | |
54 | rn32_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 |
66 | global ASM_PFX(InternalX86RdRand64)\r |
67 | ASM_PFX(InternalX86RdRand64):\r | |
55745c24 JJ |
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 | |
81 | rn64_ret:\r | |
82 | xor eax, eax\r | |
83 | ret ; return with failure status\r | |
84 | \r |