1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
;; rdrand.asm - written and placed in public domain by Jeffrey Walton and Uri Blumenthal.
;; Copyright assigned to the Crypto++ project.
;; This ASM file provides RDRAND to downlevel Microsoft tool chains.
;; Everything "just works" under Visual Studio. Other platforms will
;; have to run MASM/MASM-64 and then link to the object files.
;; set ASFLAGS=/nologo /D_M_X86 /W3 /Cx /Zi /safeseh
;; set ASFLAGS64=/nologo /D_M_X64 /W3 /Cx /Zi
;; "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\ml.exe" %ASFLAGS% /Fo rdrand-x86.obj /c rdrand.asm
;; "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\amd64\ml64.exe" %ASFLAGS64% /Fo rdrand-x64.obj /c rdrand.asm
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
TITLE MASM_RDRAND_GenerateBlock source file
SUBTITLE Microsoft specific ASM code to utilize RDRAND for down level Microsoft toolchains
PUBLIC MASM_RDRAND_GenerateBlock
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; C/C++ Function prototypes (both are fastcall)
;; X86:
;; extern "C" void __fastcall MASM_RDRAND_GenerateBlock(byte* ptr, size_t size);
;; X64:
;; extern "C" void __fastcall MASM_RDRAND_GenerateBlock(byte* ptr, size_t size);
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
IFDEF _M_X86 ;; Set via the command line
.486
.MODEL FLAT
;; Fastcall calling conventions exports
ALIAS <@MASM_RDRAND_GenerateBlock@8> = <MASM_RDRAND_GenerateBlock>
ENDIF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
IFDEF _M_X86 ;; Set via the command line
.CODE
ALIGN 8
OPTION PROLOGUE:NONE
OPTION EPILOGUE:NONE
;; No need for Load_Arguments due to fastcall
;; ECX (in): arg1, byte* buffer
;; EDX (in): arg2, size_t bsize
MASM_RDRAND_GenerateBlock PROC ;; arg1:DWORD, arg2:DWORD
MWSIZE EQU 04h ;; machine word size
buffer EQU ecx
bsize EQU edx
;; Top of While loop
RDRAND_GenerateBlock_Top:
;; Check remaining size
cmp bsize, 0
je RDRAND_GenerateBlock_Return
RDRAND_Call_EAX:
;; RDRAND is not available prior to VS2012. Just emit
;; the byte codes using DB. This is `rdrand eax`.
DB 0Fh, 0C7h, 0F0h
;; If CF=1, the number returned by RDRAND is valid.
;; If CF=0, a random number was not available.
;; Retry immediately
jnc RDRAND_Call_EAX
RDRAND_succeeded:
cmp bsize, MWSIZE
jb RDRAND_Partial_Machine_Word
RDRAND_Full_Machine_Word:
mov DWORD PTR [buffer], eax
add buffer, MWSIZE ;; No need for Intel Core 2 slow workarounds, like
sub bsize, MWSIZE ;; `lea buffer,[buffer+MWSIZE]` for faster adds
;; Continue
jmp RDRAND_GenerateBlock_Top
;; 1,2,3 bytes remain
RDRAND_Partial_Machine_Word:
;; Test bit 1 to see if size is at least 2
test bsize, 2
jz RDRAND_Bit_1_Not_Set
mov WORD PTR [buffer], ax
shr eax, 16
add buffer, 2
RDRAND_Bit_1_Not_Set:
;; Test bit 0 to see if size is at least 1
test bsize, 1
jz RDRAND_Bit_0_Not_Set
mov BYTE PTR [buffer], al
;; shr ax, 8
;; add buffer, 1
RDRAND_Bit_0_Not_Set:
;; We've hit all the bits
RDRAND_GenerateBlock_Return:
;; Clear artifacts
xor eax, eax
ret
MASM_RDRAND_GenerateBlock ENDP
ENDIF ;; _M_X86
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
IFDEF _M_X64 ;; Set via the command line
.CODE
ALIGN 16
OPTION PROLOGUE:NONE
OPTION EPILOGUE:NONE
;; No need for Load_Arguments due to fastcall
;; RCX (in): arg1, byte* buffer
;; RDX (in): arg2, size_t bsize
MASM_RDRAND_GenerateBlock PROC FRAME ;; arg1:QWORD, arg2:QWORD
MWSIZE EQU 08h ;; machine word size
buffer EQU rcx
bsize EQU rdx
.endprolog
;; Top of While loop
RDRAND_GenerateBlock_Top:
;; Check remaining size
cmp bsize, 0
je RDRAND_GenerateBlock_Return
RDRAND_Call_RAX:
;; RDRAND is not available prior to VS2012. Just emit
;; the byte codes using DB. This is `rdrand rax`.
DB 048h, 0Fh, 0C7h, 0F0h
;; If CF=1, the number returned by RDRAND is valid.
;; If CF=0, a random number was not available.
;; Retry immediately
jnc RDRAND_Call_RAX
RDRAND_succeeded:
cmp bsize, MWSIZE
jb RDRAND_Partial_Machine_Word
RDRAND_Full_Machine_Word:
mov QWORD PTR [buffer], rax
add buffer, MWSIZE
sub bsize, MWSIZE
;; Continue
jmp RDRAND_GenerateBlock_Top
;; 1,2,3,4,5,6,7 bytes remain
RDRAND_Partial_Machine_Word:
;; Test bit 2 to see if size is at least 4
test bsize, 4
jz RDRAND_Bit_2_Not_Set
mov DWORD PTR [buffer], eax
shr rax, 32
add buffer, 4
RDRAND_Bit_2_Not_Set:
;; Test bit 1 to see if size is at least 2
test bsize, 2
jz RDRAND_Bit_1_Not_Set
mov WORD PTR [buffer], ax
shr eax, 16
add buffer, 2
RDRAND_Bit_1_Not_Set:
;; Test bit 0 to see if size is at least 1
test bsize, 1
jz RDRAND_Bit_0_Not_Set
mov BYTE PTR [buffer], al
;; shr ax, 8
;; add buffer, 1
RDRAND_Bit_0_Not_Set:
;; We've hit all the bits
RDRAND_GenerateBlock_Return:
;; Clear artifacts
xor rax, rax
ret
MASM_RDRAND_GenerateBlock ENDP
ENDIF ;; _M_X64
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
END
|
