xref: /freebsd/sys/arm64/arm64/disassem.c (revision b23dbabb7f3edb3f323a64f03e37be2c9a8b2a45)
1 /*-
2  * Copyright (c) 2016 Cavium
3  * All rights reserved.
4  *
5  * This software was developed by Semihalf.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 
35 #include <machine/armreg.h>
36 #include <machine/disassem.h>
37 
38 #include <ddb/ddb.h>
39 
40 #define	ARM64_MAX_TOKEN_LEN	8
41 #define	ARM64_MAX_TOKEN_CNT	10
42 
43 #define	ARM_INSN_SIZE_OFFSET	30
44 #define	ARM_INSN_SIZE_MASK	0x3
45 
46 /* Special options for instruction printing */
47 #define	OP_SIGN_EXT	(1UL << 0)	/* Sign-extend immediate value */
48 #define	OP_LITERAL	(1UL << 1)	/* Use literal (memory offset) */
49 #define	OP_MULT_4	(1UL << 2)	/* Multiply immediate by 4 */
50 #define	OP_SF32		(1UL << 3)	/* Force 32-bit access */
51 #define	OP_SF_INV	(1UL << 6)	/* SF is inverted (1 means 32 bit access) */
52 #define	OP_RD_SP	(1UL << 7)	/* Use sp for RD otherwise xzr */
53 #define	OP_RT_SP	(1UL << 8)	/* Use sp for RT otherwise xzr */
54 #define	OP_RN_SP	(1UL << 9)	/* Use sp for RN otherwise xzr */
55 #define	OP_RM_SP	(1UL << 10)	/* Use sp for RM otherwise xzr */
56 #define	OP_SHIFT_ROR	(1UL << 11)	/* Use ror shift type */
57 
58 static const char *w_reg[] = {
59 	"w0", "w1", "w2", "w3", "w4", "w5", "w6", "w7",
60 	"w8", "w9", "w10", "w11", "w12", "w13", "w14", "w15",
61 	"w16", "w17", "w18", "w19", "w20", "w21", "w22", "w23",
62 	"w24", "w25", "w26", "w27", "w28", "w29", "w30"
63 };
64 
65 static const char *x_reg[] = {
66 	"x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
67 	"x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
68 	"x16", "x17", "x18", "x19", "x20", "x21", "x22", "x23",
69 	"x24", "x25", "x26", "x27", "x28", "x29", "lr"
70 };
71 
72 static const char *shift_2[] = {
73 	"lsl", "lsr", "asr", "ror"
74 };
75 
76 static const char *extend_types[] = {
77 	"uxtb", "uxth", "uxtw", "uxtx",
78 	"sxtb", "sxth", "sxtw", "sxtx",
79 };
80 
81 /*
82  * Structure representing single token (operand) inside instruction.
83  * name   - name of operand
84  * pos    - position within the instruction (in bits)
85  * len    - operand length (in bits)
86  */
87 struct arm64_insn_token {
88 	char name[ARM64_MAX_TOKEN_LEN];
89 	int pos;
90 	int len;
91 };
92 
93 /*
94  * Define generic types for instruction printing.
95  */
96 enum arm64_format_type {
97 	/*
98 	 * OP <RD>, <RN>, <RM>{, <shift [LSL, LSR, ASR]> #imm} SF32/64
99 	 * OP <RD>, <RN>, #<imm>{, <shift [0, 12]>} SF32/64
100 	 * OP <RD>, <RM> {, <shift> #<imm> }
101 	 * OP <RN>, <RM> {, <shift> #<imm> }
102 	 */
103 	TYPE_01,
104 
105 	/*
106 	 * OP <RT>, [<XN|SP>, #<simm>]!
107 	 * OP <RT>, [<XN|SP>], #<simm>
108 	 * OP <RT>, [<XN|SP> {, #<pimm> }]
109 	 * OP <RT>, [<XN|SP>, <RM> {, EXTEND AMOUNT }]
110 	 */
111 	TYPE_02,
112 
113 	/* OP <RT>, #imm SF32/64 */
114 	TYPE_03,
115 
116 	/*
117 	 * OP <RD>, <RN|SP>, <RM> {, <extend> { #<amount> } }
118 	 * OP <RN|SP>, <RM>, {, <extend> { #<amount> } }
119 	 */
120 	TYPE_04,
121 };
122 
123 /*
124  * Structure representing single parsed instruction format.
125  * name   - opcode name
126  * format - opcode format in a human-readable way
127  * type   - syntax type for printing
128  * special_ops  - special options passed to a printer (if any)
129  * mask   - bitmask for instruction matching
130  * pattern      - pattern to look for
131  * tokens - array of tokens (operands) inside instruction
132  */
133 struct arm64_insn {
134 	char *name;
135 	char *format;
136 	enum arm64_format_type type;
137 	uint64_t special_ops;
138 	uint32_t mask;
139 	uint32_t pattern;
140 	struct arm64_insn_token tokens[ARM64_MAX_TOKEN_CNT];
141 };
142 
143 /*
144  * Specify instruction opcode format in a human-readable way. Use notation
145  * obtained from ARM Architecture Reference Manual for ARMv8-A.
146  *
147  * Format string description:
148  *  Each group must be separated by "|". Group made of 0/1 is used to
149  *  generate mask and pattern for instruction matching. Groups containing
150  *  an operand token (in format NAME(length_bits)) are used to retrieve any
151  *  operand data from the instruction. Names here must be meaningful
152  *  and match the one described in the Manual.
153  *
154  * Token description:
155  * SF     - "0" represents 32-bit access, "1" represents 64-bit access
156  * SHIFT  - type of shift (instruction dependent)
157  * IMM    - immediate value
158  * Rx     - register number
159  * OPTION - command specific options
160  * SCALE  - scaling of immediate value
161  */
162 static struct arm64_insn arm64_i[] = {
163 	{ "add", "SF(1)|0001011|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
164 	    TYPE_01, 0 },			/* add shifted register */
165 	{ "mov", "SF(1)|001000100000000000000|RN(5)|RD(5)",
166 	    TYPE_01, OP_RD_SP | OP_RN_SP },	/* mov (to/from sp) */
167 	{ "add", "SF(1)|0010001|SHIFT(2)|IMM(12)|RN(5)|RD(5)",
168 	    TYPE_01, OP_RD_SP | OP_RN_SP },	/* add immediate */
169 	{ "cmn", "SF(1)|0101011|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|11111",
170 	    TYPE_01, 0 },			/* cmn shifted register */
171 	{ "adds", "SF(1)|0101011|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
172 	    TYPE_01, 0 },			/* adds shifted register */
173 	{ "ldr", "1|SF(1)|111000010|IMM(9)|OPTION(2)|RN(5)|RT(5)",
174 	    TYPE_02, OP_SIGN_EXT },
175 	    /* ldr immediate post/pre index */
176 	{ "ldr", "1|SF(1)|11100101|IMM(12)|RN(5)|RT(5)",
177 	    TYPE_02, 0 },			/* ldr immediate unsigned */
178 	{ "ldr", "1|SF(1)|111000011|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
179 	    TYPE_02, 0 },			/* ldr register */
180 	{ "ldr", "0|SF(1)|011000|IMM(19)|RT(5)",
181 	    TYPE_03, OP_SIGN_EXT | OP_LITERAL | OP_MULT_4 },	/* ldr literal */
182 	{ "ldrb", "00|111000010|IMM(9)|OPTION(2)|RN(5)|RT(5)",
183 	    TYPE_02, OP_SIGN_EXT | OP_SF32 },
184 	    /* ldrb immediate post/pre index */
185 	{ "ldrb", "00|11100101|IMM(12)|RN(5)|RT(5)",
186 	    TYPE_02, OP_SF32 },			/* ldrb immediate unsigned */
187 	{ "ldrb", "00|111000011|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
188 	    TYPE_02, OP_SF32 },			/* ldrb register */
189 	{ "ldrh", "01|111000010|IMM(9)|OPTION(2)|RN(5)|RT(5)", TYPE_02,
190 	    OP_SIGN_EXT | OP_SF32 },
191 	    /* ldrh immediate post/pre index */
192 	{ "ldrh", "01|11100101|IMM(12)|RN(5)|RT(5)",
193 	    TYPE_02, OP_SF32 },			/* ldrh immediate unsigned */
194 	{ "ldrh", "01|111000011|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
195 	    TYPE_02, OP_SF32 },			/* ldrh register */
196 	{ "ldrsb", "001110001|SF(1)|0|IMM(9)|OPTION(2)|RN(5)|RT(5)",
197 	    TYPE_02, OP_SIGN_EXT | OP_SF_INV },
198 	    /* ldrsb immediate post/pre index */
199 	{ "ldrsb", "001110011|SF(1)|IMM(12)|RN(5)|RT(5)",\
200 	    TYPE_02, OP_SF_INV },		/* ldrsb immediate unsigned */
201 	{ "ldrsb", "001110001|SF(1)|1|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
202 	    TYPE_02,  OP_SF_INV },		/* ldrsb register */
203 	{ "ldrsh", "011110001|SF(1)|0|IMM(9)|OPTION(2)|RN(5)|RT(5)",
204 	    TYPE_02, OP_SIGN_EXT | OP_SF_INV },
205 	    /* ldrsh immediate post/pre index */
206 	{ "ldrsh", "011110011|SF(1)|IMM(12)|RN(5)|RT(5)",
207 	    TYPE_02, OP_SF_INV },		/* ldrsh immediate unsigned */
208 	{ "ldrsh", "011110001|SF(1)|1|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
209 	    TYPE_02, OP_SF_INV },		/* ldrsh register */
210 	{ "ldrsw", "10111000100|IMM(9)|OPTION(2)|RN(5)|RT(5)",
211 	    TYPE_02, OP_SIGN_EXT },
212 	    /* ldrsw immediate post/pre index */
213 	{ "ldrsw", "1011100110|IMM(12)|RN(5)|RT(5)",
214 	    TYPE_02, 0 },			/* ldrsw immediate unsigned */
215 	{ "ldrsw", "10111000101|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
216 	    TYPE_02, 0 },			/* ldrsw register */
217 	{ "ldrsw", "10011000|IMM(19)|RT(5)",
218 	    TYPE_03, OP_SIGN_EXT | OP_LITERAL | OP_MULT_4 },	/* ldrsw literal */
219 	{ "str", "1|SF(1)|111000000|IMM(9)|OPTION(2)|RN(5)|RT(5)",
220 	    TYPE_02, OP_SIGN_EXT },
221 	    /* str immediate post/pre index */
222 	{ "str", "1|SF(1)|11100100|IMM(12)|RN(5)|RT(5)",
223 	    TYPE_02, 0 },			/* str immediate unsigned */
224 	{ "str", "1|SF(1)|111000001|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
225 	    TYPE_02, 0 },			/* str register */
226 	{ "strb", "00111000000|IMM(9)|OPTION(2)|RN(5)|RT(5)",
227 	    TYPE_02, OP_SIGN_EXT | OP_SF32 },
228 	    /* strb immediate post/pre index */
229 	{ "strb", "0011100100|IMM(12)|RN(5)|RT(5)",
230 	    TYPE_02, OP_SF32 },			/* strb immediate unsigned */
231 	{ "strb", "00111000001|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
232 	    TYPE_02, OP_SF32 },			/* strb register */
233 	{ "strh", "01111000000|IMM(9)|OPTION(2)|RN(5)|RT(5)",
234 	    TYPE_02, OP_SF32 | OP_SIGN_EXT },
235 	    /* strh immediate post/pre index */
236 	{ "strh", "0111100100|IMM(12)|RN(5)|RT(5)",
237 	    TYPE_02, OP_SF32 },
238 	    /* strh immediate unsigned */
239 	{ "strh", "01111000001|RM(5)|OPTION(3)|SCALE(1)|10|RN(5)|RT(5)",
240 	    TYPE_02, OP_SF32 },
241 	    /* strh register */
242 	{ "neg", "SF(1)|1001011|SHIFT(2)|0|RM(5)|IMM(6)|11111|RD(5)",
243 	    TYPE_01, 0 },			/* neg shifted register */
244 	{ "sub", "SF(1)|1001011|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
245 	    TYPE_01, 0 },			/* sub shifted register */
246 	{ "cmp", "SF(1)|1101011|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|11111",
247 	    TYPE_01, 0 },			/* cmp shifted register */
248 	{ "negs", "SF(1)|1101011|SHIFT(2)|0|RM(5)|IMM(6)|11111|RD(5)",
249 	    TYPE_01, 0 },			/* negs shifted register */
250 	{ "subs", "SF(1)|1101011|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
251 	    TYPE_01, 0 },			/* subs shifted register */
252 	{ "mvn", "SF(1)|0101010|SHIFT(2)|1|RM(5)|IMM(6)|11111|RD(5)",
253 	    TYPE_01, OP_SHIFT_ROR },		/* mvn shifted register */
254 	{ "orn", "SF(1)|0101010|SHIFT(2)|1|RM(5)|IMM(6)|RN(5)|RD(5)",
255 	    TYPE_01, OP_SHIFT_ROR },		/* orn shifted register */
256 	{ "mov", "SF(1)|0101010000|RM(5)|000000|11111|RD(5)",
257 	    TYPE_01, 0 },			/* mov register */
258 	{ "orr", "SF(1)|0101010|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
259 	    TYPE_01, OP_SHIFT_ROR },		/* orr shifted register */
260 	{ "and", "SF(1)|0001010|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
261 	    TYPE_01, OP_SHIFT_ROR },		/* and shifted register */
262 	{ "tst", "SF(1)|1101010|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|11111",
263 	    TYPE_01, OP_SHIFT_ROR },		/* tst shifted register */
264 	{ "ands", "SF(1)|1101010|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
265 	    TYPE_01, OP_SHIFT_ROR },		/* ands shifted register */
266 	{ "bic", "SF(1)|0001010|SHIFT(2)|1|RM(5)|IMM(6)|RN(5)|RD(5)",
267 	    TYPE_01, OP_SHIFT_ROR },		/* bic shifted register */
268 	{ "bics", "SF(1)|1101010|SHIFT(2)|1|RM(5)|IMM(6)|RN(5)|RD(5)",
269 	    TYPE_01, OP_SHIFT_ROR },		/* bics shifted register */
270 	{ "eon", "SF(1)|1001010|SHIFT(2)|1|RM(5)|IMM(6)|RN(5)|RD(5)",
271 	    TYPE_01, OP_SHIFT_ROR },		/* eon shifted register */
272 	{ "eor", "SF(1)|1001010|SHIFT(2)|0|RM(5)|IMM(6)|RN(5)|RD(5)",
273 	    TYPE_01, OP_SHIFT_ROR },		/* eor shifted register */
274 	{ "add", "SF(1)|0001011001|RM(5)|OPTION(3)|IMM(3)|RN(5)|RD(5)",
275 	    TYPE_04, OP_RD_SP },		/* add extended register */
276 	{ "cmn", "SF(1)|0101011001|RM(5)|OPTION(3)|IMM(3)|RN(5)|11111",
277 	    TYPE_04, 0 },			/* cmn extended register */
278 	{ "adds", "SF(1)|0101011001|RM(5)|OPTION(3)|IMM(3)|RN(5)|RD(5)",
279 	    TYPE_04, 0 },			/* adds extended register */
280 	{ "sub", "SF(1)|1001011001|RM(5)|OPTION(3)|IMM(3)|RN(5)|RD(5)",
281 	    TYPE_04, OP_RD_SP },		/* sub extended register */
282 	{ "cmp", "SF(1)|1101011001|RM(5)|OPTION(3)|IMM(3)|RN(5)|11111",
283 	    TYPE_04, 0 },			/* cmp extended register */
284 	{ "subs", "SF(1)|1101011001|RM(5)|OPTION(3)|IMM(3)|RN(5)|RD(5)",
285 	    TYPE_04, 0 },			/* subs extended register */
286 	{ NULL, NULL }
287 };
288 
289 static void
290 arm64_disasm_generate_masks(struct arm64_insn *tab)
291 {
292 	uint32_t mask, val;
293 	int a, i;
294 	int len, ret;
295 	int token = 0;
296 	char *format;
297 	int error;
298 
299 	while (tab->name != NULL) {
300 		mask = 0;
301 		val = 0;
302 		format = tab->format;
303 		token = 0;
304 		error = 0;
305 
306 		/*
307 		 * For each entry analyze format strings from the
308 		 * left (i.e. from the MSB).
309 		 */
310 		a = (INSN_SIZE * NBBY) - 1;
311 		while (*format != '\0' && (a >= 0)) {
312 			switch (*format) {
313 			case '0':
314 				/* Bit is 0, add to mask and pattern */
315 				mask |= (1 << a);
316 				a--;
317 				format++;
318 				break;
319 			case '1':
320 				/* Bit is 1, add to mask and pattern */
321 				mask |= (1 << a);
322 				val |= (1 << a);
323 				a--;
324 				format++;
325 				break;
326 			case '|':
327 				/* skip */
328 				format++;
329 				break;
330 			default:
331 				/* Token found, copy the name */
332 				memset(tab->tokens[token].name, 0,
333 				    sizeof(tab->tokens[token].name));
334 				i = 0;
335 				while (*format != '(') {
336 					tab->tokens[token].name[i] = *format;
337 					i++;
338 					format++;
339 					if (i >= ARM64_MAX_TOKEN_LEN) {
340 						printf("ERROR: "
341 						    "token too long in op %s\n",
342 						    tab->name);
343 						error = 1;
344 						break;
345 					}
346 				}
347 				if (error != 0)
348 					break;
349 
350 				/* Read the length value */
351 				ret = sscanf(format, "(%d)", &len);
352 				if (ret == 1) {
353 					if (token >= ARM64_MAX_TOKEN_CNT) {
354 						printf("ERROR: "
355 						    "too many tokens in op %s\n",
356 						    tab->name);
357 						error = 1;
358 						break;
359 					}
360 
361 					a -= len;
362 					tab->tokens[token].pos = a + 1;
363 					tab->tokens[token].len = len;
364 					token++;
365 				}
366 
367 				/* Skip to the end of the token */
368 				while (*format != 0 && *format != '|')
369 					format++;
370 			}
371 		}
372 
373 		/* Write mask and pattern to the instruction array */
374 		tab->mask = mask;
375 		tab->pattern = val;
376 
377 		/*
378 		 * If we got here, format string must be parsed and "a"
379 		 * should point to -1. If it's not, wrong number of bits
380 		 * in format string. Mark this as invalid and prevent
381 		 * from being matched.
382 		 */
383 		if (*format != 0 || (a != -1) || (error != 0)) {
384 			tab->mask = 0;
385 			tab->pattern = 0xffffffff;
386 			printf("ERROR: skipping instruction op %s\n",
387 			    tab->name);
388 		}
389 
390 		tab++;
391 	}
392 }
393 
394 static int
395 arm64_disasm_read_token(struct arm64_insn *insn, u_int opcode,
396     const char *token, int *val)
397 {
398 	int i;
399 
400 	for (i = 0; i < ARM64_MAX_TOKEN_CNT; i++) {
401 		if (strcmp(insn->tokens[i].name, token) == 0) {
402 			*val = (opcode >> insn->tokens[i].pos &
403 			    ((1 << insn->tokens[i].len) - 1));
404 			return (0);
405 		}
406 	}
407 
408 	return (EINVAL);
409 }
410 
411 static int
412 arm64_disasm_read_token_sign_ext(struct arm64_insn *insn, u_int opcode,
413     const char *token, int *val)
414 {
415 	int i;
416 	int msk;
417 
418 	for (i = 0; i < ARM64_MAX_TOKEN_CNT; i++) {
419 		if (strcmp(insn->tokens[i].name, token) == 0) {
420 			msk = (1 << insn->tokens[i].len) - 1;
421 			*val = ((opcode >> insn->tokens[i].pos) & msk);
422 
423 			/* If last bit is 1, sign-extend the value */
424 			if (*val & (1 << (insn->tokens[i].len - 1)))
425 				*val |= ~msk;
426 
427 			return (0);
428 		}
429 	}
430 
431 	return (EINVAL);
432 }
433 
434 static const char *
435 arm64_disasm_reg_extend(int sf, int option, int rd, int rn, int amount)
436 {
437 	bool is_sp, lsl_preferred_uxtw, lsl_preferred_uxtx, lsl_preferred;
438 
439 	is_sp = rd == 31 || rn == 31;
440 	lsl_preferred_uxtw = sf == 0 && option == 2;
441 	lsl_preferred_uxtx = sf == 1 && option == 3;
442 	lsl_preferred = is_sp && (lsl_preferred_uxtw || lsl_preferred_uxtx);
443 
444 	/*
445 	 * LSL may be omitted when <amount> is 0.
446 	 * In all other cases <extend> is required.
447 	 */
448 	if (lsl_preferred && amount == 0)
449 		return (NULL);
450 	if (lsl_preferred)
451 		return ("lsl");
452 	return (extend_types[option]);
453 }
454 
455 static const char *
456 arm64_w_reg(int num, int wsp)
457 {
458 	if (num == 31)
459 		return (wsp != 0 ? "wsp" : "wzr");
460 	return (w_reg[num]);
461 }
462 
463 static const char *
464 arm64_x_reg(int num, int sp)
465 {
466 	if (num == 31)
467 		return (sp != 0 ? "sp" : "xzr");
468 	return (x_reg[num]);
469 }
470 
471 static const char *
472 arm64_reg(int b64, int num, int sp)
473 {
474 	if (b64 != 0)
475 		return (arm64_x_reg(num, sp));
476 	return (arm64_w_reg(num, sp));
477 }
478 
479 /*
480  * Decodes OPTION(3) to get <Xn|Wn> register or <WZR|XZR>
481  * for extended register instruction.
482  */
483 static const char *
484 arm64_disasm_reg_width(int option, int reg)
485 {
486 	if (option == 3 || option == 7)
487 		return (arm64_x_reg(reg, 0));
488 	return (arm64_w_reg(reg, 0));
489 }
490 
491 vm_offset_t
492 disasm(const struct disasm_interface *di, vm_offset_t loc, int altfmt)
493 {
494 	struct arm64_insn *i_ptr = arm64_i;
495 	uint32_t insn;
496 	int matchp;
497 	int ret;
498 	int shift, rm, rt, rd, rn, imm, sf, idx, option, scale, amount;
499 	int sign_ext;
500 	bool rm_absent, rd_absent, rn_absent;
501 	/* Indicate if immediate should be outside or inside brackets */
502 	int inside;
503 	/* Print exclamation mark if pre-incremented */
504 	int pre;
505 	/* Indicate if x31 register should be printed as sp or xzr */
506 	int rm_sp, rt_sp, rd_sp, rn_sp;
507 	/* Indicate if shift type ror is supported */
508 	bool has_shift_ror;
509 
510 	const char *extend;
511 
512 	/* Initialize defaults, all are 0 except SF indicating 64bit access */
513 	shift = rd = rm = rn = imm = idx = option = amount = scale = 0;
514 	sign_ext = 0;
515 	sf = 1;
516 	extend = NULL;
517 
518 	matchp = 0;
519 	insn = di->di_readword(loc);
520 	while (i_ptr->name) {
521 		/* If mask is 0 then the parser was not initialized yet */
522 		if ((i_ptr->mask != 0) &&
523 		    ((insn & i_ptr->mask) == i_ptr->pattern)) {
524 			matchp = 1;
525 			break;
526 		}
527 		i_ptr++;
528 	}
529 	if (matchp == 0)
530 		goto undefined;
531 
532 	/* Global options */
533 	if (i_ptr->special_ops & OP_SF32)
534 		sf = 0;
535 
536 	/* Global optional tokens */
537 	arm64_disasm_read_token(i_ptr, insn, "SF", &sf);
538 	if (i_ptr->special_ops & OP_SF_INV)
539 		sf = 1 - sf;
540 	if (arm64_disasm_read_token(i_ptr, insn, "SIGN", &sign_ext) == 0)
541 		sign_ext = 1 - sign_ext;
542 	if (i_ptr->special_ops & OP_SIGN_EXT)
543 		sign_ext = 1;
544 	if (sign_ext != 0)
545 		arm64_disasm_read_token_sign_ext(i_ptr, insn, "IMM", &imm);
546 	else
547 		arm64_disasm_read_token(i_ptr, insn, "IMM", &imm);
548 	if (i_ptr->special_ops & OP_MULT_4)
549 		imm <<= 2;
550 
551 	rm_sp = i_ptr->special_ops & OP_RM_SP;
552 	rt_sp = i_ptr->special_ops & OP_RT_SP;
553 	rd_sp = i_ptr->special_ops & OP_RD_SP;
554 	rn_sp = i_ptr->special_ops & OP_RN_SP;
555 
556 	has_shift_ror = i_ptr->special_ops & OP_SHIFT_ROR;
557 
558 	/* Print opcode by type */
559 	switch (i_ptr->type) {
560 	case TYPE_01:
561 		/*
562 		 * OP <RD>, <RN>, <RM>{, <shift [LSL, LSR, ASR]> #<imm>} SF32/64
563 		 * OP <RD>, <RN>, #<imm>{, <shift [0, 12]>} SF32/64
564 		 * OP <RD>, <RM> {, <shift> #<imm> }
565 		 * OP <RN>, <RM> {, <shift> #<imm> }
566 		 */
567 
568 		rd_absent = arm64_disasm_read_token(i_ptr, insn, "RD", &rd);
569 		rn_absent = arm64_disasm_read_token(i_ptr, insn, "RN", &rn);
570 		rm_absent = arm64_disasm_read_token(i_ptr, insn, "RM", &rm);
571 		arm64_disasm_read_token(i_ptr, insn, "SHIFT", &shift);
572 
573 		/*
574 		 * if shift type is RESERVED for shifted register instruction,
575 		 * print undefined
576 		 */
577 		if (shift == 3 && !has_shift_ror)
578 			goto undefined;
579 
580 		di->di_printf("%s\t", i_ptr->name);
581 
582 		/*
583 		 * If RD and RN are present, we will display the following
584 		 * patterns:
585 		 * - OP <RD>, <RN>, <RM>{, <shift [LSL, LSR, ASR]> #<imm>} SF32/64
586 		 * - OP <RD>, <RN>, #<imm>{, <shift [0, 12]>} SF32/64
587 		 * Otherwise if only RD is present:
588 		 * - OP <RD>, <RM> {, <shift> #<imm> }
589 		 * Otherwise if only RN is present:
590 		 * - OP <RN>, <RM> {, <shift> #<imm> }
591 		 */
592 		if (!rd_absent && !rn_absent)
593 			di->di_printf("%s, %s", arm64_reg(sf, rd, rd_sp),
594 			    arm64_reg(sf, rn, rn_sp));
595 		else if (!rd_absent)
596 			di->di_printf("%s", arm64_reg(sf, rd, rd_sp));
597 		else
598 			di->di_printf("%s", arm64_reg(sf, rn, rn_sp));
599 
600 		/* If RM is present use it, otherwise use immediate notation */
601 		if (!rm_absent) {
602 			di->di_printf(", %s", arm64_reg(sf, rm, rm_sp));
603 			if (imm != 0)
604 				di->di_printf(", %s #%d", shift_2[shift], imm);
605 		} else {
606 			if (imm != 0 || shift != 0)
607 				di->di_printf(", #0x%x", imm);
608 			if (shift != 0)
609 				di->di_printf(" lsl #12");
610 		}
611 		break;
612 	case TYPE_02:
613 		/*
614 		 * OP <RT>, [<XN|SP>, #<simm>]!
615 		 * OP <RT>, [<XN|SP>], #<simm>
616 		 * OP <RT>, [<XN|SP> {, #<pimm> }]
617 		 * OP <RT>, [<XN|SP>, <RM> {, EXTEND AMOUNT }]
618 		 */
619 
620 		/* Mandatory tokens */
621 		ret = arm64_disasm_read_token(i_ptr, insn, "RT", &rt);
622 		ret |= arm64_disasm_read_token(i_ptr, insn, "RN", &rn);
623 		if (ret != 0) {
624 			printf("ERROR: "
625 			    "Missing mandatory token for op %s type %d\n",
626 			    i_ptr->name, i_ptr->type);
627 			goto undefined;
628 		}
629 
630 		/* Optional tokens */
631 		arm64_disasm_read_token(i_ptr, insn, "OPTION", &option);
632 		arm64_disasm_read_token(i_ptr, insn, "SCALE", &scale);
633 		rm_absent = arm64_disasm_read_token(i_ptr, insn, "RM", &rm);
634 
635 		if (rm_absent) {
636 			/*
637 			 * In unsigned operation, shift immediate value
638 			 * and reset options to default.
639 			 */
640 			if (sign_ext == 0) {
641 				imm = imm << ((insn >> ARM_INSN_SIZE_OFFSET) &
642 				    ARM_INSN_SIZE_MASK);
643 				option = 0;
644 			}
645 			switch (option) {
646 			case 0x0:
647 				pre = 0;
648 				inside = 1;
649 				break;
650 			case 0x1:
651 				pre = 0;
652 				inside = 0;
653 				break;
654 			case 0x2:
655 			default:
656 				pre = 1;
657 				inside = 1;
658 				break;
659 			}
660 
661 			di->di_printf("%s\t%s, ", i_ptr->name,
662 			    arm64_reg(sf, rt, rt_sp));
663 			if (inside != 0) {
664 				di->di_printf("[%s", arm64_x_reg(rn, 1));
665 				if (imm != 0)
666 					di->di_printf(", #%d", imm);
667 				di->di_printf("]");
668 			} else {
669 				di->di_printf("[%s]", arm64_x_reg(rn, 1));
670 				if (imm != 0)
671 					di->di_printf(", #%d", imm);
672 			}
673 			if (pre != 0)
674 				di->di_printf("!");
675 		} else {
676 			/* Last bit of option field determines 32/64 bit offset */
677 			di->di_printf("%s\t%s, [%s, %s", i_ptr->name,
678 			    arm64_reg(sf, rt, rt_sp), arm64_x_reg(rn, 1),
679 			    arm64_reg(option & 1, rm, rm_sp));
680 
681 			if (scale == 0)
682 				amount = 0;
683 			else {
684 				/* Calculate amount, it's op(31:30) */
685 				amount = (insn >> ARM_INSN_SIZE_OFFSET) &
686 			            ARM_INSN_SIZE_MASK;
687 			}
688 
689 			switch (option) {
690 			case 0x2:
691 				di->di_printf(", uxtw #%d", amount);
692 				break;
693 			case 0x3:
694 				if (scale != 0)
695 					di->di_printf(", lsl #%d", amount);
696 				break;
697 			case 0x6:
698 				di->di_printf(", sxtw #%d", amount);
699 				break;
700 			case 0x7:
701 				di->di_printf(", sxtx #%d", amount);
702 				break;
703 			default:
704 				di->di_printf(", rsv");
705 				break;
706 			}
707 			di->di_printf("]");
708 		}
709 
710 		break;
711 
712 	case TYPE_03:
713 		/* OP <RT>, #imm SF32/64 */
714 
715 		/* Mandatory tokens */
716 		ret = arm64_disasm_read_token(i_ptr, insn, "RT", &rt);
717 		if (ret != 0) {
718 			printf("ERROR: "
719 			    "Missing mandatory token for op %s type %d\n",
720 			    i_ptr->name, i_ptr->type);
721 			goto undefined;
722 		}
723 
724 		di->di_printf("%s\t%s, ", i_ptr->name, arm64_reg(sf, rt, rt_sp));
725 		if (i_ptr->special_ops & OP_LITERAL)
726 			di->di_printf("0x%lx", loc + imm);
727 		else
728 			di->di_printf("#%d", imm);
729 
730 		break;
731 
732 	case TYPE_04:
733 		/*
734 		 * OP <RD>, <RN|SP>, <RM> {, <extend> { #<amount> } }
735 		 * OP <RN|SP>, <RM>, {, <extend> { #<amount> } }
736 		 */
737 
738 		arm64_disasm_read_token(i_ptr, insn, "RN", &rn);
739 		arm64_disasm_read_token(i_ptr, insn, "RM", &rm);
740 		arm64_disasm_read_token(i_ptr, insn, "OPTION", &option);
741 
742 		rd_absent = arm64_disasm_read_token(i_ptr, insn, "RD", &rd);
743 		extend = arm64_disasm_reg_extend(sf, option, rd, rn, imm);
744 
745 		di->di_printf("%s\t", i_ptr->name);
746 
747 		if (!rd_absent)
748 			di->di_printf("%s, ", arm64_reg(sf, rd, rd_sp));
749 
750 		di->di_printf("%s, ", arm64_reg(sf, rn, 1));
751 
752 		if (sf != 0)
753 			di->di_printf("%s",
754 			    arm64_disasm_reg_width(option, rm));
755 		else
756 			di->di_printf("%s", arm64_w_reg(rm, 0));
757 
758 		if (extend != NULL)
759 			di->di_printf(", %s #%d", extend, imm);
760 
761 		break;
762 	default:
763 		goto undefined;
764 	}
765 
766 	di->di_printf("\n");
767 	return (loc + INSN_SIZE);
768 
769 undefined:
770 	di->di_printf("undefined\t%08x\n", insn);
771 	return (loc + INSN_SIZE);
772 }
773 
774 /* Parse format strings at the very beginning */
775 SYSINIT(arm64_disasm_generate_masks, SI_SUB_DDB_SERVICES, SI_ORDER_FIRST,
776     arm64_disasm_generate_masks, arm64_i);
777