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[deliverable/binutils-gdb.git] / sim / aarch64 / decode.h
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1/* decode.h -- Prototypes for AArch64 simulator decoder functions.
2
b811d2c2 3 Copyright (C) 2015-2020 Free Software Foundation, Inc.
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4
5 Contributed by Red Hat.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22#ifndef _DECODE_H
23#define _DECODE_H
24
25#include <sys/types.h>
26#include "cpustate.h"
27
28/* Codes used in conditional instructions
29
30 These are passed to conditional operations to identify which
31 condition to test for. */
32
33typedef enum CondCode
34{
35 EQ = 0x0, /* meaning Z == 1 */
36 NE = 0x1, /* meaning Z == 0 */
37 HS = 0x2, /* meaning C == 1 */
38 CS = HS,
39 LO = 0x3, /* meaning C == 0 */
40 CC = LO,
41 MI = 0x4, /* meaning N == 1 */
42 PL = 0x5, /* meaning N == 0 */
43 VS = 0x6, /* meaning V == 1 */
44 VC = 0x7, /* meaning V == 0 */
45 HI = 0x8, /* meaning C == 1 && Z == 0 */
46 LS = 0x9, /* meaning !(C == 1 && Z == 0) */
47 GE = 0xa, /* meaning N == V */
48 LT = 0xb, /* meaning N != V */
49 GT = 0xc, /* meaning Z == 0 && N == V */
50 LE = 0xd, /* meaning !(Z == 0 && N == V) */
51 AL = 0xe, /* meaning ANY */
52 NV = 0xf /* ditto */
53} CondCode;
54
55/* Certain addressing modes for load require pre or post writeback of
56 the computed address to a base register. */
57
58typedef enum WriteBack
59{
60 Post = 0,
61 Pre = 1,
62 NoWriteBack = -1
63} WriteBack;
64
65/* Certain addressing modes for load require an offset to
66 be optionally scaled so the decode needs to pass that
67 through to the execute routine. */
68
69typedef enum Scaling
70{
71 Unscaled = 0,
72 Scaled = 1,
73 NoScaling = -1
74} Scaling;
75
76/* When we do have to scale we do so by shifting using
77 log(bytes in data element - 1) as the shift count.
78 so we don't have to scale offsets when loading
79 bytes. */
80
81typedef enum ScaleShift
82{
83 ScaleShift16 = 1,
84 ScaleShift32 = 2,
85 ScaleShift64 = 3,
86 ScaleShift128 = 4
87} ScaleShift;
88
89/* One of the addressing modes for load requires a 32-bit register
90 value to be either zero- or sign-extended for these instructions
91 UXTW or SXTW should be passed.
92
93 Arithmetic register data processing operations can optionally
94 extend a portion of the second register value for these
95 instructions the value supplied must identify the portion of the
96 register which is to be zero- or sign-exended. */
97
98typedef enum Extension
99{
100 UXTB = 0,
101 UXTH = 1,
102 UXTW = 2,
103 UXTX = 3,
104 SXTB = 4,
105 SXTH = 5,
106 SXTW = 6,
107 SXTX = 7,
108 NoExtension = -1
109} Extension;
110
111/* Arithmetic and logical register data processing operations
112 optionally perform a shift on the second register value. */
113
114typedef enum Shift
115{
116 LSL = 0,
117 LSR = 1,
118 ASR = 2,
119 ROR = 3
120} Shift;
121
122/* Bit twiddling helpers for instruction decode. */
123
124/* 32 bit mask with bits [hi,...,lo] set. */
125static inline uint32_t
126mask32 (int hi, int lo)
127{
128 int nbits = (hi + 1) - lo;
129 return ((1 << nbits) - 1) << lo;
130}
131
132/* 64 bit mask with bits [hi,...,lo] set. */
133static inline uint64_t
134mask64 (int hi, int lo)
135{
136 int nbits = (hi + 1) - lo;
137 return ((1L << nbits) - 1) << lo;
138}
139
140/* Pick bits [hi,...,lo] from val. */
141static inline uint32_t
142pick32 (uint32_t val, int hi, int lo)
143{
144 return val & mask32 (hi, lo);
145}
146
147/* Pick bits [hi,...,lo] from val. */
148static inline uint64_t
149pick64 (uint64_t val, int hi, int lo)
150{
151 return val & mask64 (hi, lo);
152}
153
154/* Pick bits [hi,...,lo] from val and shift to [(hi-(newlo - lo)),newlo]. */
155static inline uint32_t
156pickshift32 (uint32_t val, int hi, int lo, int newlo)
157{
158 uint32_t bits = pick32 (val, hi, lo);
159
160 if (lo < newlo)
161 return bits << (newlo - lo);
162
163 return bits >> (lo - newlo);
164}
165
166/* Mask [hi,lo] and shift down to start at bit 0. */
167static inline uint32_t
168pickbits32 (uint32_t val, int hi, int lo)
169{
170 return pick32 (val, hi, lo) >> lo;
171}
172
173/* Mask [hi,lo] and shift down to start at bit 0. */
174static inline uint64_t
175pickbits64 (uint64_t val, int hi, int lo)
176{
177 return pick64 (val, hi, lo) >> lo;
178}
179
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180static inline uint32_t
181uimm (uint32_t val, int hi, int lo)
182{
183 return pickbits32 (val, hi, lo);
184}
185
186static inline int32_t
187simm32 (uint32_t val, int hi, int lo)
188{
189 union
190 {
191 uint32_t u;
192 int32_t n;
193 } x;
194
195 x.u = val << (31 - hi);
196 return x.n >> (31 - hi + lo);
197}
198
199static inline int64_t
200simm64 (uint64_t val, int hi, int lo)
201{
202 union
203 {
204 uint64_t u;
205 int64_t n;
206 } x;
207
208 x.u = val << (63 - hi);
209 return x.n >> (63 - hi + lo);
210}
211
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212/* Operation decode.
213 Bits [28,24] are the primary dispatch vector. */
214
215static inline uint32_t
216dispatchGroup (uint32_t val)
217{
218 return pickshift32 (val, 28, 25, 0);
219}
220
221/* The 16 possible values for bits [28,25] identified by tags which
222 map them to the 5 main instruction groups LDST, DPREG, ADVSIMD,
223 BREXSYS and DPIMM.
224
225 An extra group PSEUDO is included in one of the unallocated ranges
226 for simulator-specific pseudo-instructions. */
227
228enum DispatchGroup
229{
230 GROUP_PSEUDO_0000,
231 GROUP_UNALLOC_0001,
232 GROUP_UNALLOC_0010,
233 GROUP_UNALLOC_0011,
234 GROUP_LDST_0100,
235 GROUP_DPREG_0101,
236 GROUP_LDST_0110,
237 GROUP_ADVSIMD_0111,
238 GROUP_DPIMM_1000,
239 GROUP_DPIMM_1001,
240 GROUP_BREXSYS_1010,
241 GROUP_BREXSYS_1011,
242 GROUP_LDST_1100,
243 GROUP_DPREG_1101,
244 GROUP_LDST_1110,
245 GROUP_ADVSIMD_1111
246};
247
248/* Bits [31, 29] of a Pseudo are the secondary dispatch vector. */
249
250static inline uint32_t
251dispatchPseudo (uint32_t val)
252{
253 return pickshift32 (val, 31, 29, 0);
254}
255
256/* The 8 possible values for bits [31,29] in a Pseudo Instruction.
257 Bits [28,25] are always 0000. */
258
259enum DispatchPseudo
260{
261 PSEUDO_UNALLOC_000, /* Unallocated. */
262 PSEUDO_UNALLOC_001, /* Ditto. */
263 PSEUDO_UNALLOC_010, /* Ditto. */
264 PSEUDO_UNALLOC_011, /* Ditto. */
265 PSEUDO_UNALLOC_100, /* Ditto. */
266 PSEUDO_UNALLOC_101, /* Ditto. */
267 PSEUDO_CALLOUT_110, /* CALLOUT -- bits [24,0] identify call/ret sig. */
268 PSEUDO_HALT_111 /* HALT -- bits [24, 0] identify halt code. */
269};
270
271/* Bits [25, 23] of a DPImm are the secondary dispatch vector. */
272
273static inline uint32_t
274dispatchDPImm (uint32_t instr)
275{
276 return pickshift32 (instr, 25, 23, 0);
277}
278
279/* The 8 possible values for bits [25,23] in a Data Processing Immediate
280 Instruction. Bits [28,25] are always 100_. */
281
282enum DispatchDPImm
283{
284 DPIMM_PCADR_000, /* PC-rel-addressing. */
285 DPIMM_PCADR_001, /* Ditto. */
286 DPIMM_ADDSUB_010, /* Add/Subtract (immediate). */
287 DPIMM_ADDSUB_011, /* Ditto. */
288 DPIMM_LOG_100, /* Logical (immediate). */
289 DPIMM_MOV_101, /* Move Wide (immediate). */
290 DPIMM_BITF_110, /* Bitfield. */
291 DPIMM_EXTR_111 /* Extract. */
292};
293
294/* Bits [29,28:26] of a LS are the secondary dispatch vector. */
295
296static inline uint32_t
297dispatchLS (uint32_t instr)
298{
299 return ( pickshift32 (instr, 29, 28, 1)
300 | pickshift32 (instr, 26, 26, 0));
301}
302
303/* The 8 possible values for bits [29,28:26] in a Load/Store
304 Instruction. Bits [28,25] are always _1_0. */
305
306enum DispatchLS
307{
308 LS_EXCL_000, /* Load/store exclusive (includes some unallocated). */
309 LS_ADVSIMD_001, /* AdvSIMD load/store (various -- includes some unallocated). */
310 LS_LIT_010, /* Load register literal (includes some unallocated). */
311 LS_LIT_011, /* Ditto. */
312 LS_PAIR_100, /* Load/store register pair (various). */
313 LS_PAIR_101, /* Ditto. */
314 LS_OTHER_110, /* Other load/store formats. */
315 LS_OTHER_111 /* Ditto. */
316};
317
318/* Bits [28:24:21] of a DPReg are the secondary dispatch vector. */
319
320static inline uint32_t
321dispatchDPReg (uint32_t instr)
322{
323 return ( pickshift32 (instr, 28, 28, 2)
324 | pickshift32 (instr, 24, 24, 1)
325 | pickshift32 (instr, 21, 21, 0));
326}
327
328/* The 8 possible values for bits [28:24:21] in a Data Processing
329 Register Instruction. Bits [28,25] are always _101. */
330
331enum DispatchDPReg
332{
333 DPREG_LOG_000, /* Logical (shifted register). */
334 DPREG_LOG_001, /* Ditto. */
335 DPREG_ADDSHF_010, /* Add/subtract (shifted register). */
336 DPREG_ADDEXT_011, /* Add/subtract (extended register). */
337 DPREG_ADDCOND_100, /* Add/subtract (with carry) AND
338 Cond compare/select AND
339 Data Processing (1/2 source). */
340 DPREG_UNALLOC_101, /* Unallocated. */
341 DPREG_3SRC_110, /* Data Processing (3 source). */
342 DPREG_3SRC_111 /* Data Processing (3 source). */
343};
344
345/* bits [31,29] of a BrExSys are the secondary dispatch vector. */
346
347static inline uint32_t
348dispatchBrExSys (uint32_t instr)
349{
350 return pickbits32 (instr, 31, 29);
351}
352
353/* The 8 possible values for bits [31,29] in a Branch/Exception/System
354 Instruction. Bits [28,25] are always 101_. */
355
356enum DispatchBr
357{
358 BR_IMM_000, /* Unconditional branch (immediate). */
359 BR_IMMCMP_001, /* Compare & branch (immediate) AND
360 Test & branch (immediate). */
361 BR_IMMCOND_010, /* Conditional branch (immediate) AND Unallocated. */
362 BR_UNALLOC_011, /* Unallocated. */
363 BR_IMM_100, /* Unconditional branch (immediate). */
364 BR_IMMCMP_101, /* Compare & branch (immediate) AND
365 Test & branch (immediate). */
366 BR_REG_110, /* Unconditional branch (register) AND System AND
367 Excn gen AND Unallocated. */
368 BR_UNALLOC_111 /* Unallocated. */
369};
370
371/* TODO still need to provide secondary decode and dispatch for
372 AdvSIMD Insructions with instr[28,25] = 0111 or 1111. */
373
374#endif /* _DECODE_H */
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