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Side by Side Diff: src/trusted/validator_ragel/unreviewed/decoding.h

Issue 11000033: Move validator_x86_XX.rl out of unreviewed. (Closed) Base URL: svn://svn.chromium.org/native_client/trunk/src/native_client/
Patch Set: Created 7 years, 9 months ago
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1 /*
2 * Copyright (c) 2012 The Native Client Authors. All rights reserved.
3 * Use of this source code is governed by a BSD-style license that can be
4 * found in the LICENSE file.
5 */
6
7 /*
8 * This file contains common parts of x86-32 and x86-64 internals (inline
9 * functions and defines).
10 *
11 * We only include simple schematic diagrams here. For full description see
12 * AMD/Intel manuals.
13 */
14
15 #ifndef NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_RAGEL_DECODING_H_
16 #define NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_RAGEL_DECODING_H_
17
18 #include "native_client/src/trusted/validator_ragel/decoder.h"
19
20 #if NACL_WINDOWS
21 # define FORCEINLINE __forceinline
22 #else
23 # define FORCEINLINE __inline __attribute__ ((always_inline))
24 #endif
25
26
27 /*
28 * Opcode with register number embedded:
29 *
30 * 7 6 5 4 3 2 1 0
31 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
32 * │ Opcode │ register number ┃
33 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
34 */
35 static FORCEINLINE uint8_t RegFromOpcode(uint8_t modrm) {
36 return modrm & 0x07;
37 }
38
39 /*
40 * ModRM byte format:
41 *
42 * 7 6 5 4 3 2 1 0
43 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
44 * │ mod │ reg │ r/m ┃
45 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
46 */
47 static FORCEINLINE uint8_t ModFromModRM(uint8_t modrm) {
48 return modrm >> 6;
49 }
50
51 static FORCEINLINE uint8_t RegFromModRM(uint8_t modrm) {
52 return (modrm & 0x38) >> 3;
53 }
54
55 static FORCEINLINE uint8_t RMFromModRM(uint8_t modrm) {
56 return modrm & 0x07;
57 }
58
59 /*
60 * SIB byte format:
61 *
62 * 7 6 5 4 3 2 1 0
63 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
64 * │ scale │ index │ base ┃
65 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
66 */
67 static FORCEINLINE uint8_t ScaleFromSIB(uint8_t sib) {
68 return sib >> 6;
69 }
70
71 static FORCEINLINE uint8_t IndexFromSIB(uint8_t sib) {
72 return (sib & 0x38) >> 3;
73 }
74
75 static FORCEINLINE uint8_t BaseFromSIB(uint8_t sib) {
76 return sib & 0x07;
77 }
78
79 /*
80 * REX byte format:
81 *
82 * 7 6 5 4 3 2 1 0
83 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
84 * │ 0 │ 1 │ 0 │ 0 │ W │ R │ X │ B ┃
85 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
86 */
87
88 enum {
89 REX_B = 1,
90 REX_X = 2,
91 REX_R = 4,
92 REX_W = 8
93 };
94
95 static FORCEINLINE uint8_t BaseExtentionFromREX(uint8_t rex) {
96 return (rex & REX_B) << 3;
97 }
98
99 static FORCEINLINE uint8_t IndexExtentionFromREX(uint8_t rex) {
100 return (rex & REX_X) << 2;
101 }
102
103 static FORCEINLINE uint8_t RegisterExtentionFromREX(uint8_t rex) {
104 return (rex & REX_R) << 1;
105 }
106
107 /*
108 * VEX 2nd byte format:
109 *
110 * 7 6 5 4 3 2 1 0
111 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
112 * │ ¬R │ ¬X │ ¬B │ opcode map selector ┃
113 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
114 */
115
116 enum {
117 VEX_MAP1 = 0x01,
118 VEX_MAP2 = 0x02,
119 VEX_MAP3 = 0x03,
120 VEX_MAP8 = 0x08,
121 VEX_MAP9 = 0x09,
122 VEX_MAPA = 0x0a,
123 VEX_B = 0x20,
124 VEX_X = 0x40,
125 VEX_R = 0x80,
126 VEX_W = 0x80
127 };
128
129 static FORCEINLINE uint8_t BaseExtentionFromVEX(uint8_t vex2) {
130 return ((~vex2) & VEX_B) >> 2;
131 }
132
133 static FORCEINLINE uint8_t IndexExtentionFromVEX(uint8_t vex2) {
134 return ((~vex2) & VEX_X) >> 3;
135 }
136
137 static FORCEINLINE uint8_t RegisterExtentionFromVEX(uint8_t vex2) {
138 return ((~vex2) & VEX_R) >> 4;
139 }
140
141 /*
142 * VEX 3rd byte format:
143 *
144 * 7 6 5 4 3 2 1 0
145 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
146 * │ W │ ¬vvvv (register number) │ L │ pp ┃
147 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
148 */
149
150 static FORCEINLINE uint8_t GetOperandFromVexIA32(uint8_t vex3) {
151 return ((~vex3) & 0x38) >> 3;
152 }
153
154 static FORCEINLINE uint8_t GetOperandFromVexAMD64(uint8_t vex3) {
155 return ((~vex3) & 0x78) >> 3;
156 }
157
158 /*
159 * is4 byte format:
160 *
161 * 7 6 5 4 3 2 1 0
162 * ┌───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┒
163 * │ vvvv (register number) │ 0 │ 0 │ imm2 or zero ┃
164 * ┕━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┷━━━━━━━┛
165 */
166 static FORCEINLINE uint8_t RegisterFromIS4(uint8_t is4) {
167 return is4 >> 4;
168 }
169
170 /*
171 * SignExtendXXBit is used to sign-extend XX-bit value to unsigned 64-bit value.
172 *
173 * To do that you need to pass unsigned value of smaller then 64-bit size
174 * to this function: it will be converted to signed value and then
175 * sign-extended to become 64-bit value.
176 *
177 * Smaller values can be obtained by restricting this value further (which is
178 * safe according to the C language specification: see 6.2.1.2 in C90 and
179 * 6.3.1.3.2 in C99 specification).
180 *
181 * Note that these operations are safe but slightly unusual: they come very
182 * close to the edge of what "well-behaved C program is not supposed to do",
183 * but they stay on the "safe" side of this boundary. Specifically: this
184 * behavior triggers "implementation-defined behavior" (see 6.2.1.2 in C90
185 * specification and 6.3.1.3.3 in C99 specification) which sounds suspiciously
186 * similar to the dreaded "undefined behavior", but in reality these two are
187 * quite different: any program which triggers "undefined behavior" is not a
188 * valid C program at all, but program which triggers "implementation-defined
189 * behavior" is quite valid C program. What this program actually *does*
190 * depends on the specification of a given C compiler: each particular
191 * implementation must decide for itself what it'll do in this particular case
192 * and *stick* *to* *it*. If the implementation uses two's-complement negative
193 * numbers (and all the implementation which can compile this code *must*
194 * support two's-complement arythmetic - see 7.18.1.1 in C99 specification) then
195 * the easiest thing to do is to do what we need here - this is what all known
196 * compilers for all known platforms are actually doing.
197 */
198 static FORCEINLINE uint64_t SignExtend8Bit(uint64_t value) {
199 return (int8_t)value;
200 }
201
202 static FORCEINLINE uint64_t SignExtend16Bit(uint64_t value) {
203 return (int16_t)value;
204 }
205
206 static FORCEINLINE uint64_t SignExtend32Bit(uint64_t value) {
207 return (int32_t)value;
208 }
209
210 static FORCEINLINE uint64_t AnyFieldValue8bit(const uint8_t *start) {
211 return *start;
212 }
213
214 static FORCEINLINE uint64_t AnyFieldValue16bit(const uint8_t *start) {
215 return (start[0] + 256U * start[1]);
216 }
217
218 static FORCEINLINE uint64_t AnyFieldValue32bit(const uint8_t *start) {
219 return (start[0] + 256U * (start[1] + 256U * (start[2] + 256U * (start[3]))));
220 }
221 static FORCEINLINE uint64_t AnyFieldValue64bit(const uint8_t *start) {
222 return (*start + 256ULL * (start[1] + 256ULL * (start[2] + 256ULL *
223 (start[3] + 256ULL * (start[4] + 256ULL * (start[5] + 256ULL *
224 (start[6] + 256ULL * start[7])))))));
225 }
226
227 static const uint8_t index_registers[] = {
228 /* Note how REG_RIZ falls out of the pattern. */
229 REG_RAX, REG_RCX, REG_RDX, REG_RBX,
230 REG_RIZ, REG_RBP, REG_RSI, REG_RDI,
231 REG_R8, REG_R9, REG_R10, REG_R11,
232 REG_R12, REG_R13, REG_R14, REG_R15
233 };
234
235 #endif /* NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_RAGEL_DECODING_H_ */
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