xref: /openbmc/qemu/target/hexagon/decode.c (revision d0bf492f)
1 /*
2  *  Copyright(c) 2019-2023 Qualcomm Innovation Center, Inc. All Rights Reserved.
3  *
4  *  This program is free software; you can redistribute it and/or modify
5  *  it under the terms of the GNU General Public License as published by
6  *  the Free Software Foundation; either version 2 of the License, or
7  *  (at your option) any later version.
8  *
9  *  This program is distributed in the hope that it will be useful,
10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  *  GNU General Public License for more details.
13  *
14  *  You should have received a copy of the GNU General Public License
15  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #include "qemu/osdep.h"
19 #include "iclass.h"
20 #include "attribs.h"
21 #include "genptr.h"
22 #include "decode.h"
23 #include "insn.h"
24 #include "printinsn.h"
25 #include "mmvec/decode_ext_mmvec.h"
26 
27 #define fZXTN(N, M, VAL) ((VAL) & ((1LL << (N)) - 1))
28 
29 enum {
30     EXT_IDX_noext = 0,
31     EXT_IDX_noext_AFTER = 4,
32     EXT_IDX_mmvec = 4,
33     EXT_IDX_mmvec_AFTER = 8,
34     XX_LAST_EXT_IDX
35 };
36 
37 /*
38  *  Certain operand types represent a non-contiguous set of values.
39  *  For example, the compound compare-and-jump instruction can only access
40  *  registers R0-R7 and R16-23.
41  *  This table represents the mapping from the encoding to the actual values.
42  */
43 
44 #define DEF_REGMAP(NAME, ELEMENTS, ...) \
45     static const unsigned int DECODE_REGISTER_##NAME[ELEMENTS] = \
46     { __VA_ARGS__ };
47         /* Name   Num Table */
48 DEF_REGMAP(R_16,  16, 0, 1, 2, 3, 4, 5, 6, 7, 16, 17, 18, 19, 20, 21, 22, 23)
49 DEF_REGMAP(R__8,  8,  0, 2, 4, 6, 16, 18, 20, 22)
50 DEF_REGMAP(R_8,   8,  0, 1, 2, 3, 4, 5, 6, 7)
51 
52 #define DECODE_MAPPED_REG(OPNUM, NAME) \
53     insn->regno[OPNUM] = DECODE_REGISTER_##NAME[insn->regno[OPNUM]];
54 
55 typedef struct {
56     const struct DectreeTable *table_link;
57     const struct DectreeTable *table_link_b;
58     Opcode opcode;
59     enum {
60         DECTREE_ENTRY_INVALID,
61         DECTREE_TABLE_LINK,
62         DECTREE_SUBINSNS,
63         DECTREE_EXTSPACE,
64         DECTREE_TERMINAL
65     } type;
66 } DectreeEntry;
67 
68 typedef struct DectreeTable {
69     unsigned int (*lookup_function)(int startbit, int width, uint32_t opcode);
70     unsigned int size;
71     unsigned int startbit;
72     unsigned int width;
73     const DectreeEntry table[];
74 } DectreeTable;
75 
76 #define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT) \
77     static const DectreeTable dectree_table_##TAG;
78 #define TABLE_LINK(TABLE)                     /* NOTHING */
79 #define TERMINAL(TAG, ENC)                    /* NOTHING */
80 #define SUBINSNS(TAG, CLASSA, CLASSB, ENC)    /* NOTHING */
81 #define EXTSPACE(TAG, ENC)                    /* NOTHING */
82 #define INVALID()                             /* NOTHING */
83 #define DECODE_END_TABLE(...)                 /* NOTHING */
84 #define DECODE_MATCH_INFO(...)                /* NOTHING */
85 #define DECODE_LEGACY_MATCH_INFO(...)         /* NOTHING */
86 #define DECODE_OPINFO(...)                    /* NOTHING */
87 
88 #include "dectree_generated.h.inc"
89 
90 #undef DECODE_OPINFO
91 #undef DECODE_MATCH_INFO
92 #undef DECODE_LEGACY_MATCH_INFO
93 #undef DECODE_END_TABLE
94 #undef INVALID
95 #undef TERMINAL
96 #undef SUBINSNS
97 #undef EXTSPACE
98 #undef TABLE_LINK
99 #undef DECODE_NEW_TABLE
100 #undef DECODE_SEPARATOR_BITS
101 
102 #define DECODE_SEPARATOR_BITS(START, WIDTH) NULL, START, WIDTH
103 #define DECODE_NEW_TABLE_HELPER(TAG, SIZE, FN, START, WIDTH) \
104     static const DectreeTable dectree_table_##TAG = { \
105         .size = SIZE, \
106         .lookup_function = FN, \
107         .startbit = START, \
108         .width = WIDTH, \
109         .table = {
110 #define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT) \
111     DECODE_NEW_TABLE_HELPER(TAG, SIZE, WHATNOT)
112 
113 #define TABLE_LINK(TABLE) \
114     { .type = DECTREE_TABLE_LINK, .table_link = &dectree_table_##TABLE },
115 #define TERMINAL(TAG, ENC) \
116     { .type = DECTREE_TERMINAL, .opcode = TAG  },
117 #define SUBINSNS(TAG, CLASSA, CLASSB, ENC) \
118     { \
119         .type = DECTREE_SUBINSNS, \
120         .table_link = &dectree_table_DECODE_SUBINSN_##CLASSA, \
121         .table_link_b = &dectree_table_DECODE_SUBINSN_##CLASSB \
122     },
123 #define EXTSPACE(TAG, ENC) { .type = DECTREE_EXTSPACE },
124 #define INVALID() { .type = DECTREE_ENTRY_INVALID, .opcode = XX_LAST_OPCODE },
125 
126 #define DECODE_END_TABLE(...) } };
127 
128 #define DECODE_MATCH_INFO(...)                /* NOTHING */
129 #define DECODE_LEGACY_MATCH_INFO(...)         /* NOTHING */
130 #define DECODE_OPINFO(...)                    /* NOTHING */
131 
132 #include "dectree_generated.h.inc"
133 
134 #undef DECODE_OPINFO
135 #undef DECODE_MATCH_INFO
136 #undef DECODE_LEGACY_MATCH_INFO
137 #undef DECODE_END_TABLE
138 #undef INVALID
139 #undef TERMINAL
140 #undef SUBINSNS
141 #undef EXTSPACE
142 #undef TABLE_LINK
143 #undef DECODE_NEW_TABLE
144 #undef DECODE_NEW_TABLE_HELPER
145 #undef DECODE_SEPARATOR_BITS
146 
147 static const DectreeTable dectree_table_DECODE_EXT_EXT_noext = {
148     .size = 1, .lookup_function = NULL, .startbit = 0, .width = 0,
149     .table = {
150         { .type = DECTREE_ENTRY_INVALID, .opcode = XX_LAST_OPCODE },
151     }
152 };
153 
154 static const DectreeTable *ext_trees[XX_LAST_EXT_IDX];
155 
156 static void decode_ext_init(void)
157 {
158     int i;
159     for (i = EXT_IDX_noext; i < EXT_IDX_noext_AFTER; i++) {
160         ext_trees[i] = &dectree_table_DECODE_EXT_EXT_noext;
161     }
162     for (i = EXT_IDX_mmvec; i < EXT_IDX_mmvec_AFTER; i++) {
163         ext_trees[i] = &dectree_table_DECODE_EXT_EXT_mmvec;
164     }
165 }
166 
167 typedef struct {
168     uint32_t mask;
169     uint32_t match;
170 } DecodeITableEntry;
171 
172 #define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT)  /* NOTHING */
173 #define TABLE_LINK(TABLE)                     /* NOTHING */
174 #define TERMINAL(TAG, ENC)                    /* NOTHING */
175 #define SUBINSNS(TAG, CLASSA, CLASSB, ENC)    /* NOTHING */
176 #define EXTSPACE(TAG, ENC)                    /* NOTHING */
177 #define INVALID()                             /* NOTHING */
178 #define DECODE_END_TABLE(...)                 /* NOTHING */
179 #define DECODE_OPINFO(...)                    /* NOTHING */
180 
181 #define DECODE_MATCH_INFO_NORMAL(TAG, MASK, MATCH) \
182     [TAG] = { \
183         .mask = MASK, \
184         .match = MATCH, \
185     },
186 
187 #define DECODE_MATCH_INFO_NULL(TAG, MASK, MATCH) \
188     [TAG] = { .match = ~0 },
189 
190 #define DECODE_MATCH_INFO(...) DECODE_MATCH_INFO_NORMAL(__VA_ARGS__)
191 #define DECODE_LEGACY_MATCH_INFO(...) /* NOTHING */
192 
193 static const DecodeITableEntry decode_itable[XX_LAST_OPCODE] = {
194 #include "dectree_generated.h.inc"
195 };
196 
197 #undef DECODE_MATCH_INFO
198 #define DECODE_MATCH_INFO(...) DECODE_MATCH_INFO_NULL(__VA_ARGS__)
199 
200 #undef DECODE_LEGACY_MATCH_INFO
201 #define DECODE_LEGACY_MATCH_INFO(...) DECODE_MATCH_INFO_NORMAL(__VA_ARGS__)
202 
203 static const DecodeITableEntry decode_legacy_itable[XX_LAST_OPCODE] = {
204 #include "dectree_generated.h.inc"
205 };
206 
207 #undef DECODE_OPINFO
208 #undef DECODE_MATCH_INFO
209 #undef DECODE_LEGACY_MATCH_INFO
210 #undef DECODE_END_TABLE
211 #undef INVALID
212 #undef TERMINAL
213 #undef SUBINSNS
214 #undef EXTSPACE
215 #undef TABLE_LINK
216 #undef DECODE_NEW_TABLE
217 #undef DECODE_SEPARATOR_BITS
218 
219 void decode_init(void)
220 {
221     decode_ext_init();
222 }
223 
224 void decode_send_insn_to(Packet *packet, int start, int newloc)
225 {
226     Insn tmpinsn;
227     int direction;
228     int i;
229     if (start == newloc) {
230         return;
231     }
232     if (start < newloc) {
233         /* Move towards end */
234         direction = 1;
235     } else {
236         /* move towards beginning */
237         direction = -1;
238     }
239     for (i = start; i != newloc; i += direction) {
240         tmpinsn = packet->insn[i];
241         packet->insn[i] = packet->insn[i + direction];
242         packet->insn[i + direction] = tmpinsn;
243     }
244 }
245 
246 /* Fill newvalue registers with the correct regno */
247 static void
248 decode_fill_newvalue_regno(Packet *packet)
249 {
250     int i, use_regidx, offset, def_idx, dst_idx;
251     uint16_t def_opcode, use_opcode;
252     char *dststr;
253 
254     for (i = 1; i < packet->num_insns; i++) {
255         if (GET_ATTRIB(packet->insn[i].opcode, A_DOTNEWVALUE) &&
256             !GET_ATTRIB(packet->insn[i].opcode, A_EXTENSION)) {
257             use_opcode = packet->insn[i].opcode;
258 
259             /* It's a store, so we're adjusting the Nt field */
260             if (GET_ATTRIB(use_opcode, A_STORE)) {
261                 use_regidx = strchr(opcode_reginfo[use_opcode], 't') -
262                     opcode_reginfo[use_opcode];
263             } else {    /* It's a Jump, so we're adjusting the Ns field */
264                 use_regidx = strchr(opcode_reginfo[use_opcode], 's') -
265                     opcode_reginfo[use_opcode];
266             }
267 
268             /*
269              * What's encoded at the N-field is the offset to who's producing
270              * the value.  Shift off the LSB which indicates odd/even register,
271              * then walk backwards and skip over the constant extenders.
272              */
273             offset = packet->insn[i].regno[use_regidx] >> 1;
274             def_idx = i - offset;
275             for (int j = 0; j < offset; j++) {
276                 if (GET_ATTRIB(packet->insn[i - j - 1].opcode, A_IT_EXTENDER)) {
277                     def_idx--;
278                 }
279             }
280 
281             /*
282              * Check for a badly encoded N-field which points to an instruction
283              * out-of-range
284              */
285             g_assert(!((def_idx < 0) || (def_idx > (packet->num_insns - 1))));
286 
287             /*
288              * packet->insn[def_idx] is the producer
289              * Figure out which type of destination it produces
290              * and the corresponding index in the reginfo
291              */
292             def_opcode = packet->insn[def_idx].opcode;
293             dststr = strstr(opcode_wregs[def_opcode], "Rd");
294             if (dststr) {
295                 dststr = strchr(opcode_reginfo[def_opcode], 'd');
296             } else {
297                 dststr = strstr(opcode_wregs[def_opcode], "Rx");
298                 if (dststr) {
299                     dststr = strchr(opcode_reginfo[def_opcode], 'x');
300                 } else {
301                     dststr = strstr(opcode_wregs[def_opcode], "Re");
302                     if (dststr) {
303                         dststr = strchr(opcode_reginfo[def_opcode], 'e');
304                     } else {
305                         dststr = strstr(opcode_wregs[def_opcode], "Ry");
306                         if (dststr) {
307                             dststr = strchr(opcode_reginfo[def_opcode], 'y');
308                         } else {
309                             g_assert_not_reached();
310                         }
311                     }
312                 }
313             }
314             g_assert(dststr != NULL);
315 
316             /* Now patch up the consumer with the register number */
317             dst_idx = dststr - opcode_reginfo[def_opcode];
318             packet->insn[i].regno[use_regidx] =
319                 packet->insn[def_idx].regno[dst_idx];
320             /*
321              * We need to remember who produces this value to later
322              * check if it was dynamically cancelled
323              */
324             packet->insn[i].new_value_producer_slot =
325                 packet->insn[def_idx].slot;
326         }
327     }
328 }
329 
330 /* Split CJ into a compare and a jump */
331 static void decode_split_cmpjump(Packet *pkt)
332 {
333     int last, i;
334     int numinsns = pkt->num_insns;
335 
336     /*
337      * First, split all compare-jumps.
338      * The compare is sent to the end as a new instruction.
339      * Do it this way so we don't reorder dual jumps. Those need to stay in
340      * original order.
341      */
342     for (i = 0; i < numinsns; i++) {
343         /* It's a cmp-jump */
344         if (GET_ATTRIB(pkt->insn[i].opcode, A_NEWCMPJUMP)) {
345             last = pkt->num_insns;
346             pkt->insn[last] = pkt->insn[i];    /* copy the instruction */
347             pkt->insn[last].part1 = true;      /* last insn does the CMP */
348             pkt->insn[i].part1 = false;        /* existing insn does the JUMP */
349             pkt->num_insns++;
350         }
351     }
352 
353     /* Now re-shuffle all the compares back to the beginning */
354     for (i = 0; i < pkt->num_insns; i++) {
355         if (pkt->insn[i].part1) {
356             decode_send_insn_to(pkt, i, 0);
357         }
358     }
359 }
360 
361 static bool decode_opcode_can_jump(int opcode)
362 {
363     if ((GET_ATTRIB(opcode, A_JUMP)) ||
364         (GET_ATTRIB(opcode, A_CALL)) ||
365         (opcode == J2_trap0) ||
366         (opcode == J2_pause)) {
367         /* Exception to A_JUMP attribute */
368         if (opcode == J4_hintjumpr) {
369             return false;
370         }
371         return true;
372     }
373 
374     return false;
375 }
376 
377 static bool decode_opcode_ends_loop(int opcode)
378 {
379     return GET_ATTRIB(opcode, A_HWLOOP0_END) ||
380            GET_ATTRIB(opcode, A_HWLOOP1_END);
381 }
382 
383 /* Set the is_* fields in each instruction */
384 static void decode_set_insn_attr_fields(Packet *pkt)
385 {
386     int i;
387     int numinsns = pkt->num_insns;
388     uint16_t opcode;
389 
390     pkt->pkt_has_cof = false;
391     pkt->pkt_has_multi_cof = false;
392     pkt->pkt_has_endloop = false;
393     pkt->pkt_has_dczeroa = false;
394 
395     for (i = 0; i < numinsns; i++) {
396         opcode = pkt->insn[i].opcode;
397         if (pkt->insn[i].part1) {
398             continue;    /* Skip compare of cmp-jumps */
399         }
400 
401         if (GET_ATTRIB(opcode, A_DCZEROA)) {
402             pkt->pkt_has_dczeroa = true;
403         }
404 
405         if (GET_ATTRIB(opcode, A_STORE)) {
406             if (GET_ATTRIB(opcode, A_SCALAR_STORE) &&
407                 !GET_ATTRIB(opcode, A_MEMSIZE_0B)) {
408                 if (pkt->insn[i].slot == 0) {
409                     pkt->pkt_has_store_s0 = true;
410                 } else {
411                     pkt->pkt_has_store_s1 = true;
412                 }
413             }
414         }
415 
416         if (decode_opcode_can_jump(opcode)) {
417             if (pkt->pkt_has_cof) {
418                 pkt->pkt_has_multi_cof = true;
419             }
420             pkt->pkt_has_cof = true;
421         }
422 
423         pkt->insn[i].is_endloop = decode_opcode_ends_loop(opcode);
424 
425         pkt->pkt_has_endloop |= pkt->insn[i].is_endloop;
426 
427         if (pkt->pkt_has_endloop) {
428             if (pkt->pkt_has_cof) {
429                 pkt->pkt_has_multi_cof = true;
430             }
431             pkt->pkt_has_cof = true;
432         }
433     }
434 }
435 
436 /*
437  * Shuffle for execution
438  * Move stores to end (in same order as encoding)
439  * Move compares to beginning (for use by .new insns)
440  */
441 static void decode_shuffle_for_execution(Packet *packet)
442 {
443     bool changed = false;
444     int i;
445     bool flag;    /* flag means we've seen a non-memory instruction */
446     int n_mems;
447     int last_insn = packet->num_insns - 1;
448 
449     /*
450      * Skip end loops, somehow an end loop is getting in and messing
451      * up the order
452      */
453     if (decode_opcode_ends_loop(packet->insn[last_insn].opcode)) {
454         last_insn--;
455     }
456 
457     do {
458         changed = false;
459         /*
460          * Stores go last, must not reorder.
461          * Cannot shuffle stores past loads, either.
462          * Iterate backwards.  If we see a non-memory instruction,
463          * then a store, shuffle the store to the front.  Don't shuffle
464          * stores wrt each other or a load.
465          */
466         for (flag = false, n_mems = 0, i = last_insn; i >= 0; i--) {
467             int opcode = packet->insn[i].opcode;
468 
469             if (flag && GET_ATTRIB(opcode, A_STORE)) {
470                 decode_send_insn_to(packet, i, last_insn - n_mems);
471                 n_mems++;
472                 changed = true;
473             } else if (GET_ATTRIB(opcode, A_STORE)) {
474                 n_mems++;
475             } else if (GET_ATTRIB(opcode, A_LOAD)) {
476                 /*
477                  * Don't set flag, since we don't want to shuffle a
478                  * store past a load
479                  */
480                 n_mems++;
481             } else if (GET_ATTRIB(opcode, A_DOTNEWVALUE)) {
482                 /*
483                  * Don't set flag, since we don't want to shuffle past
484                  * a .new value
485                  */
486             } else {
487                 flag = true;
488             }
489         }
490 
491         if (changed) {
492             continue;
493         }
494         /* Compares go first, may be reordered wrt each other */
495         for (flag = false, i = 0; i < last_insn + 1; i++) {
496             int opcode = packet->insn[i].opcode;
497 
498             if ((strstr(opcode_wregs[opcode], "Pd4") ||
499                  strstr(opcode_wregs[opcode], "Pe4")) &&
500                 GET_ATTRIB(opcode, A_STORE) == 0) {
501                 /* This should be a compare (not a store conditional) */
502                 if (flag) {
503                     decode_send_insn_to(packet, i, 0);
504                     changed = true;
505                     continue;
506                 }
507             } else if (GET_ATTRIB(opcode, A_IMPLICIT_WRITES_P3) &&
508                        !decode_opcode_ends_loop(packet->insn[i].opcode)) {
509                 /*
510                  * spNloop instruction
511                  * Don't reorder endloops; they are not valid for .new uses,
512                  * and we want to match HW
513                  */
514                 if (flag) {
515                     decode_send_insn_to(packet, i, 0);
516                     changed = true;
517                     continue;
518                 }
519             } else if (GET_ATTRIB(opcode, A_IMPLICIT_WRITES_P0) &&
520                        !GET_ATTRIB(opcode, A_NEWCMPJUMP)) {
521                 if (flag) {
522                     decode_send_insn_to(packet, i, 0);
523                     changed = true;
524                     continue;
525                 }
526             } else {
527                 flag = true;
528             }
529         }
530         if (changed) {
531             continue;
532         }
533     } while (changed);
534 
535     /*
536      * If we have a .new register compare/branch, move that to the very
537      * very end, past stores
538      */
539     for (i = 0; i < last_insn; i++) {
540         if (GET_ATTRIB(packet->insn[i].opcode, A_DOTNEWVALUE)) {
541             decode_send_insn_to(packet, i, last_insn);
542             break;
543         }
544     }
545 }
546 
547 static void
548 apply_extender(Packet *pkt, int i, uint32_t extender)
549 {
550     int immed_num;
551     uint32_t base_immed;
552 
553     immed_num = opcode_which_immediate_is_extended(pkt->insn[i].opcode);
554     base_immed = pkt->insn[i].immed[immed_num];
555 
556     pkt->insn[i].immed[immed_num] = extender | fZXTN(6, 32, base_immed);
557 }
558 
559 static void decode_apply_extenders(Packet *packet)
560 {
561     int i;
562     for (i = 0; i < packet->num_insns; i++) {
563         if (GET_ATTRIB(packet->insn[i].opcode, A_IT_EXTENDER)) {
564             packet->insn[i + 1].extension_valid = true;
565             apply_extender(packet, i + 1, packet->insn[i].immed[0]);
566         }
567     }
568 }
569 
570 static void decode_remove_extenders(Packet *packet)
571 {
572     int i, j;
573     for (i = 0; i < packet->num_insns; i++) {
574         if (GET_ATTRIB(packet->insn[i].opcode, A_IT_EXTENDER)) {
575             /* Remove this one by moving the remaining instructions down */
576             for (j = i;
577                 (j < packet->num_insns - 1) && (j < INSTRUCTIONS_MAX - 1);
578                 j++) {
579                 packet->insn[j] = packet->insn[j + 1];
580             }
581             packet->num_insns--;
582         }
583     }
584 }
585 
586 static SlotMask get_valid_slots(const Packet *pkt, unsigned int slot)
587 {
588     if (GET_ATTRIB(pkt->insn[slot].opcode, A_EXTENSION)) {
589         return mmvec_ext_decode_find_iclass_slots(pkt->insn[slot].opcode);
590     } else {
591         return find_iclass_slots(pkt->insn[slot].opcode,
592                                  pkt->insn[slot].iclass);
593     }
594 }
595 
596 #define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT)     /* NOTHING */
597 #define TABLE_LINK(TABLE)                        /* NOTHING */
598 #define TERMINAL(TAG, ENC)                       /* NOTHING */
599 #define SUBINSNS(TAG, CLASSA, CLASSB, ENC)       /* NOTHING */
600 #define EXTSPACE(TAG, ENC)                       /* NOTHING */
601 #define INVALID()                                /* NOTHING */
602 #define DECODE_END_TABLE(...)                    /* NOTHING */
603 #define DECODE_MATCH_INFO(...)                   /* NOTHING */
604 #define DECODE_LEGACY_MATCH_INFO(...)            /* NOTHING */
605 
606 #define DECODE_REG(REGNO, WIDTH, STARTBIT) \
607     insn->regno[REGNO] = ((encoding >> STARTBIT) & ((1 << WIDTH) - 1));
608 
609 #define DECODE_IMPL_REG(REGNO, VAL) \
610     insn->regno[REGNO] = VAL;
611 
612 #define DECODE_IMM(IMMNO, WIDTH, STARTBIT, VALSTART) \
613     insn->immed[IMMNO] |= (((encoding >> STARTBIT) & ((1 << WIDTH) - 1))) << \
614                           (VALSTART);
615 
616 #define DECODE_IMM_SXT(IMMNO, WIDTH) \
617     insn->immed[IMMNO] = ((((int32_t)insn->immed[IMMNO]) << (32 - WIDTH)) >> \
618                           (32 - WIDTH));
619 
620 #define DECODE_IMM_NEG(IMMNO, WIDTH) \
621     insn->immed[IMMNO] = -insn->immed[IMMNO];
622 
623 #define DECODE_IMM_SHIFT(IMMNO, SHAMT)                                 \
624     if ((!insn->extension_valid) || \
625         (insn->which_extended != IMMNO)) { \
626         insn->immed[IMMNO] <<= SHAMT; \
627     }
628 
629 #define DECODE_OPINFO(TAG, BEH) \
630     case TAG: \
631         { BEH  } \
632         break; \
633 
634 /*
635  * Fill in the operands of the instruction
636  * dectree_generated.h.inc has a DECODE_OPINFO entry for each opcode
637  * For example,
638  *     DECODE_OPINFO(A2_addi,
639  *          DECODE_REG(0,5,0)
640  *          DECODE_REG(1,5,16)
641  *          DECODE_IMM(0,7,21,9)
642  *          DECODE_IMM(0,9,5,0)
643  *          DECODE_IMM_SXT(0,16)
644  * with the macros defined above, we'll fill in a switch statement
645  * where each case is an opcode tag.
646  */
647 static void
648 decode_op(Insn *insn, Opcode tag, uint32_t encoding)
649 {
650     insn->immed[0] = 0;
651     insn->immed[1] = 0;
652     insn->opcode = tag;
653     if (insn->extension_valid) {
654         insn->which_extended = opcode_which_immediate_is_extended(tag);
655     }
656 
657     switch (tag) {
658 #include "dectree_generated.h.inc"
659     default:
660         break;
661     }
662 
663     insn->generate = opcode_genptr[tag];
664 
665     insn->iclass = iclass_bits(encoding);
666 }
667 
668 #undef DECODE_REG
669 #undef DECODE_IMPL_REG
670 #undef DECODE_IMM
671 #undef DECODE_IMM_SHIFT
672 #undef DECODE_OPINFO
673 #undef DECODE_MATCH_INFO
674 #undef DECODE_LEGACY_MATCH_INFO
675 #undef DECODE_END_TABLE
676 #undef INVALID
677 #undef TERMINAL
678 #undef SUBINSNS
679 #undef EXTSPACE
680 #undef TABLE_LINK
681 #undef DECODE_NEW_TABLE
682 #undef DECODE_SEPARATOR_BITS
683 
684 static unsigned int
685 decode_subinsn_tablewalk(Insn *insn, const DectreeTable *table,
686                          uint32_t encoding)
687 {
688     unsigned int i;
689     Opcode opc;
690     if (table->lookup_function) {
691         i = table->lookup_function(table->startbit, table->width, encoding);
692     } else {
693         i = extract32(encoding, table->startbit, table->width);
694     }
695     if (table->table[i].type == DECTREE_TABLE_LINK) {
696         return decode_subinsn_tablewalk(insn, table->table[i].table_link,
697                                         encoding);
698     } else if (table->table[i].type == DECTREE_TERMINAL) {
699         opc = table->table[i].opcode;
700         if ((encoding & decode_itable[opc].mask) != decode_itable[opc].match) {
701             return 0;
702         }
703         decode_op(insn, opc, encoding);
704         return 1;
705     } else {
706         return 0;
707     }
708 }
709 
710 static unsigned int get_insn_a(uint32_t encoding)
711 {
712     return extract32(encoding, 0, 13);
713 }
714 
715 static unsigned int get_insn_b(uint32_t encoding)
716 {
717     return extract32(encoding, 16, 13);
718 }
719 
720 static unsigned int
721 decode_insns_tablewalk(Insn *insn, const DectreeTable *table,
722                        uint32_t encoding)
723 {
724     unsigned int i;
725     unsigned int a, b;
726     Opcode opc;
727     if (table->lookup_function) {
728         i = table->lookup_function(table->startbit, table->width, encoding);
729     } else {
730         i = extract32(encoding, table->startbit, table->width);
731     }
732     if (table->table[i].type == DECTREE_TABLE_LINK) {
733         return decode_insns_tablewalk(insn, table->table[i].table_link,
734                                       encoding);
735     } else if (table->table[i].type == DECTREE_SUBINSNS) {
736         a = get_insn_a(encoding);
737         b = get_insn_b(encoding);
738         b = decode_subinsn_tablewalk(insn, table->table[i].table_link_b, b);
739         a = decode_subinsn_tablewalk(insn + 1, table->table[i].table_link, a);
740         if ((a == 0) || (b == 0)) {
741             return 0;
742         }
743         return 2;
744     } else if (table->table[i].type == DECTREE_TERMINAL) {
745         opc = table->table[i].opcode;
746         if ((encoding & decode_itable[opc].mask) != decode_itable[opc].match) {
747             if ((encoding & decode_legacy_itable[opc].mask) !=
748                 decode_legacy_itable[opc].match) {
749                 return 0;
750             }
751         }
752         decode_op(insn, opc, encoding);
753         return 1;
754     } else if (table->table[i].type == DECTREE_EXTSPACE) {
755         /*
756          * For now, HVX will be the only coproc
757          */
758         return decode_insns_tablewalk(insn, ext_trees[EXT_IDX_mmvec], encoding);
759     } else {
760         return 0;
761     }
762 }
763 
764 static unsigned int
765 decode_insns(Insn *insn, uint32_t encoding)
766 {
767     const DectreeTable *table;
768     if (parse_bits(encoding) != 0) {
769         /* Start with PP table - 32 bit instructions */
770         table = &dectree_table_DECODE_ROOT_32;
771     } else {
772         /* start with EE table - duplex instructions */
773         table = &dectree_table_DECODE_ROOT_EE;
774     }
775     return decode_insns_tablewalk(insn, table, encoding);
776 }
777 
778 static void decode_add_endloop_insn(Insn *insn, int loopnum)
779 {
780     if (loopnum == 10) {
781         insn->opcode = J2_endloop01;
782         insn->generate = opcode_genptr[J2_endloop01];
783     } else if (loopnum == 1) {
784         insn->opcode = J2_endloop1;
785         insn->generate = opcode_genptr[J2_endloop1];
786     } else if (loopnum == 0) {
787         insn->opcode = J2_endloop0;
788         insn->generate = opcode_genptr[J2_endloop0];
789     } else {
790         g_assert_not_reached();
791     }
792 }
793 
794 static bool decode_parsebits_is_loopend(uint32_t encoding32)
795 {
796     uint32_t bits = parse_bits(encoding32);
797     return bits == 0x2;
798 }
799 
800 static bool has_valid_slot_assignment(Packet *pkt)
801 {
802     int used_slots = 0;
803     for (int i = 0; i < pkt->num_insns; i++) {
804         int slot_mask;
805         Insn *insn = &pkt->insn[i];
806         if (decode_opcode_ends_loop(insn->opcode)) {
807             /* We overload slot 0 for endloop. */
808             continue;
809         }
810         slot_mask = 1 << insn->slot;
811         if (used_slots & slot_mask) {
812             return false;
813         }
814         used_slots |= slot_mask;
815     }
816     return true;
817 }
818 
819 static bool
820 decode_set_slot_number(Packet *pkt)
821 {
822     int slot;
823     int i;
824     bool hit_mem_insn = false;
825     bool hit_duplex = false;
826     bool slot0_found = false;
827     bool slot1_found = false;
828     int slot1_iidx = 0;
829 
830     /*
831      * The slots are encoded in reverse order
832      * For each instruction, count down until you find a suitable slot
833      */
834     for (i = 0, slot = 3; i < pkt->num_insns; i++) {
835         SlotMask valid_slots = get_valid_slots(pkt, i);
836 
837         while (!(valid_slots & (1 << slot))) {
838             slot--;
839         }
840         pkt->insn[i].slot = slot;
841         if (slot) {
842             /* I've assigned the slot, now decrement it for the next insn */
843             slot--;
844         }
845     }
846 
847     /* Fix the exceptions - mem insns to slot 0,1 */
848     for (i = pkt->num_insns - 1; i >= 0; i--) {
849         /* First memory instruction always goes to slot 0 */
850         if ((GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE) ||
851              GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE_PACKET_RULES)) &&
852             !hit_mem_insn) {
853             hit_mem_insn = true;
854             pkt->insn[i].slot = 0;
855             continue;
856         }
857 
858         /* Next memory instruction always goes to slot 1 */
859         if ((GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE) ||
860              GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE_PACKET_RULES)) &&
861             hit_mem_insn) {
862             pkt->insn[i].slot = 1;
863         }
864     }
865 
866     /* Fix the exceptions - duplex always slot 0,1 */
867     for (i = pkt->num_insns - 1; i >= 0; i--) {
868         /* First subinsn always goes to slot 0 */
869         if (GET_ATTRIB(pkt->insn[i].opcode, A_SUBINSN) && !hit_duplex) {
870             hit_duplex = true;
871             pkt->insn[i].slot = 0;
872             continue;
873         }
874 
875         /* Next subinsn always goes to slot 1 */
876         if (GET_ATTRIB(pkt->insn[i].opcode, A_SUBINSN) && hit_duplex) {
877             pkt->insn[i].slot = 1;
878         }
879     }
880 
881     /* Fix the exceptions - slot 1 is never empty, always aligns to slot 0 */
882     for (i = pkt->num_insns - 1; i >= 0; i--) {
883         /* Is slot0 used? */
884         if (pkt->insn[i].slot == 0) {
885             bool is_endloop = (pkt->insn[i].opcode == J2_endloop01);
886             is_endloop |= (pkt->insn[i].opcode == J2_endloop0);
887             is_endloop |= (pkt->insn[i].opcode == J2_endloop1);
888 
889             /*
890              * Make sure it's not endloop since, we're overloading
891              * slot0 for endloop
892              */
893             if (!is_endloop) {
894                 slot0_found = true;
895             }
896         }
897         /* Is slot1 used? */
898         if (pkt->insn[i].slot == 1) {
899             slot1_found = true;
900             slot1_iidx = i;
901         }
902     }
903     /* Is slot0 empty and slot1 used? */
904     if ((!slot0_found) && slot1_found) {
905         /* Then push it to slot0 */
906         pkt->insn[slot1_iidx].slot = 0;
907     }
908 
909     return has_valid_slot_assignment(pkt);
910 }
911 
912 /*
913  * decode_packet
914  * Decodes packet with given words
915  * Returns 0 on insufficient words,
916  * or number of words used on success
917  */
918 
919 int decode_packet(int max_words, const uint32_t *words, Packet *pkt,
920                   bool disas_only)
921 {
922     int num_insns = 0;
923     int words_read = 0;
924     bool end_of_packet = false;
925     int new_insns = 0;
926     int i;
927     uint32_t encoding32;
928 
929     /* Initialize */
930     memset(pkt, 0, sizeof(*pkt));
931     /* Try to build packet */
932     while (!end_of_packet && (words_read < max_words)) {
933         encoding32 = words[words_read];
934         end_of_packet = is_packet_end(encoding32);
935         new_insns = decode_insns(&pkt->insn[num_insns], encoding32);
936         g_assert(new_insns > 0);
937         /*
938          * If we saw an extender, mark next word extended so immediate
939          * decode works
940          */
941         if (pkt->insn[num_insns].opcode == A4_ext) {
942             pkt->insn[num_insns + 1].extension_valid = true;
943         }
944         num_insns += new_insns;
945         words_read++;
946     }
947 
948     pkt->num_insns = num_insns;
949     if (!end_of_packet) {
950         /* Ran out of words! */
951         return 0;
952     }
953     pkt->encod_pkt_size_in_bytes = words_read * 4;
954     pkt->pkt_has_hvx = false;
955     for (i = 0; i < num_insns; i++) {
956         pkt->pkt_has_hvx |=
957             GET_ATTRIB(pkt->insn[i].opcode, A_CVI);
958     }
959 
960     /*
961      * Check for :endloop in the parse bits
962      * Section 10.6 of the Programmer's Reference describes the encoding
963      *     The end of hardware loop 0 can be encoded with 2 words
964      *     The end of hardware loop 1 needs 3 words
965      */
966     if ((words_read == 2) && (decode_parsebits_is_loopend(words[0]))) {
967         decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 0);
968     }
969     if (words_read >= 3) {
970         bool has_loop0, has_loop1;
971         has_loop0 = decode_parsebits_is_loopend(words[0]);
972         has_loop1 = decode_parsebits_is_loopend(words[1]);
973         if (has_loop0 && has_loop1) {
974             decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 10);
975         } else if (has_loop1) {
976             decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 1);
977         } else if (has_loop0) {
978             decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 0);
979         }
980     }
981 
982     decode_apply_extenders(pkt);
983     if (!disas_only) {
984         decode_remove_extenders(pkt);
985         if (!decode_set_slot_number(pkt)) {
986             /* Invalid packet */
987             return 0;
988         }
989     }
990     decode_fill_newvalue_regno(pkt);
991 
992     if (pkt->pkt_has_hvx) {
993         mmvec_ext_decode_checks(pkt, disas_only);
994     }
995 
996     if (!disas_only) {
997         decode_shuffle_for_execution(pkt);
998         decode_split_cmpjump(pkt);
999         decode_set_insn_attr_fields(pkt);
1000     }
1001 
1002     return words_read;
1003 }
1004 
1005 /* Used for "-d in_asm" logging */
1006 int disassemble_hexagon(uint32_t *words, int nwords, bfd_vma pc,
1007                         GString *buf)
1008 {
1009     Packet pkt;
1010 
1011     if (decode_packet(nwords, words, &pkt, true) > 0) {
1012         snprint_a_pkt_disas(buf, &pkt, words, pc);
1013         return pkt.encod_pkt_size_in_bytes;
1014     } else {
1015         g_string_assign(buf, "<invalid>");
1016         return 0;
1017     }
1018 }
1019