deps/lightrec/interpreter.c

   1 // SPDX-License-Identifier: LGPL-2.1-or-later
   2 /*
   3  * Copyright (C) 2019-2021 Paul Cercueil <paul@crapouillou.net>
   4  */
   5
   6 #include "disassembler.h"
   7 #include "interpreter.h"
   8 #include "lightrec-private.h"
   9 #include "optimizer.h"
  10 #include "regcache.h"
  11
  12 #include <stdbool.h>
  13
  14 struct interpreter;
  15
  16 static u32 int_CP0(struct interpreter *inter);
  17 static u32 int_CP2(struct interpreter *inter);
  18 static u32 int_SPECIAL(struct interpreter *inter);
  19 static u32 int_META(struct interpreter *inter);
  20 static u32 int_REGIMM(struct interpreter *inter);
  21 static u32 int_branch(struct interpreter *inter, u32 pc,
  22                       union code code, bool branch);
  23
  24 typedef u32 (*lightrec_int_func_t)(struct interpreter *inter);
  25
  26 static const lightrec_int_func_t int_standard[64];
  27
  28 struct interpreter {
  29         struct lightrec_state *state;
  30         struct block *block;
  31         struct opcode *op;
  32         u32 cycles;
  33         bool delay_slot;
  34         u16 offset;
  35 };
  36
  37 static u32 int_get_branch_pc(const struct interpreter *inter)
  38 {
  39         return get_branch_pc(inter->block, inter->offset, 0);
  40 }
  41
  42 static inline u32 int_get_ds_pc(const struct interpreter *inter, s16 imm)
  43 {
  44         return get_ds_pc(inter->block, inter->offset, imm);
  45 }
  46
  47 static inline struct opcode *next_op(const struct interpreter *inter)
  48 {
  49         return &inter->op[1];
  50 }
  51
  52 static inline u32 execute(lightrec_int_func_t func, struct interpreter *inter)
  53 {
  54         return (*func)(inter);
  55 }
  56
  57 static inline u32 lightrec_int_op(struct interpreter *inter)
  58 {
  59         return execute(int_standard[inter->op->i.op], inter);
  60 }
  61
  62 static inline u32 jump_skip(struct interpreter *inter)
  63 {
  64         inter->op = next_op(inter);
  65         inter->offset++;
  66
  67         if (op_flag_sync(inter->op->flags)) {
  68                 inter->state->current_cycle += inter->cycles;
  69                 inter->cycles = 0;
  70         }
  71
  72         return lightrec_int_op(inter);
  73 }
  74
  75 static inline u32 jump_next(struct interpreter *inter)
  76 {
  77         inter->cycles += lightrec_cycles_of_opcode(inter->state, inter->op->c);
  78
  79         if (unlikely(inter->delay_slot))
  80                 return 0;
  81
  82         return jump_skip(inter);
  83 }
  84
  85 static inline u32 jump_after_branch(struct interpreter *inter)
  86 {
  87         inter->cycles += lightrec_cycles_of_opcode(inter->state, inter->op->c);
  88
  89         if (unlikely(inter->delay_slot))
  90                 return 0;
  91
  92         inter->op = next_op(inter);
  93         inter->offset++;
  94
  95         return jump_skip(inter);
  96 }
  97
  98 static void update_cycles_before_branch(struct interpreter *inter)
  99 {
 100         u32 cycles;
 101
 102         if (!inter->delay_slot) {
 103                 cycles = lightrec_cycles_of_opcode(inter->state, inter->op->c);
 104
 105                 if (!op_flag_no_ds(inter->op->flags) &&
 106                     has_delay_slot(inter->op->c))
 107                         cycles += lightrec_cycles_of_opcode(inter->state, next_op(inter)->c);
 108
 109                 inter->cycles += cycles;
 110                 inter->state->current_cycle += inter->cycles;
 111                 inter->cycles = -cycles;
 112         }
 113 }
 114
 115 static bool is_branch_taken(const u32 *reg_cache, union code op)
 116 {
 117         switch (op.i.op) {
 118         case OP_SPECIAL:
 119                 return op.r.op == OP_SPECIAL_JR || op.r.op == OP_SPECIAL_JALR;
 120         case OP_J:
 121         case OP_JAL:
 122                 return true;
 123         case OP_BEQ:
 124                 return reg_cache[op.r.rs] == reg_cache[op.r.rt];
 125         case OP_BNE:
 126                 return reg_cache[op.r.rs] != reg_cache[op.r.rt];
 127         case OP_REGIMM:
 128                 switch (op.r.rt) {
 129                 case OP_REGIMM_BLTZ:
 130                 case OP_REGIMM_BLTZAL:
 131                         return (s32)reg_cache[op.r.rs] < 0;
 132                 case OP_REGIMM_BGEZ:
 133                 case OP_REGIMM_BGEZAL:
 134                         return (s32)reg_cache[op.r.rs] >= 0;
 135                 }
 136         default:
 137                 break;
 138         }
 139
 140         return false;
 141 }
 142
 143 static u32 int_delay_slot(struct interpreter *inter, u32 pc, bool branch)
 144 {
 145         struct lightrec_state *state = inter->state;
 146         u32 *reg_cache = state->regs.gpr;
 147         struct opcode new_op, *op = next_op(inter);
 148         union code op_next;
 149         struct interpreter inter2 = {
 150                 .state = state,
 151                 .cycles = inter->cycles,
 152                 .delay_slot = true,
 153                 .block = NULL,
 154         };
 155         bool run_first_op = false, dummy_ld = false, save_rs = false,
 156              load_in_ds, branch_in_ds = false, branch_at_addr = false,
 157              branch_taken;
 158         u32 old_rs, new_rt, new_rs = 0;
 159         u32 next_pc, ds_next_pc;
 160         u32 cause, epc;
 161
 162         if (op->i.op == OP_CP0 && op->r.rs == OP_CP0_RFE) {
 163                 /* When an IRQ happens, the PSX exception handlers (when done)
 164                  * will jump back to the instruction that was executed right
 165                  * before the IRQ, unless it was a GTE opcode; in that case, it
 166                  * jumps to the instruction right after.
 167                  * Since we will never handle the IRQ right after a GTE opcode,
 168                  * but on branch boundaries, we need to adjust the return
 169                  * address so that the GTE opcode is effectively executed.
 170                  */
 171                 cause = state->regs.cp0[13];
 172                 epc = state->regs.cp0[14];
 173
 174                 if (!(cause & 0x7c) && epc == pc - 4)
 175                         pc -= 4;
 176         }
 177
 178         if (inter->delay_slot) {
 179                 /* The branch opcode was in a delay slot of another branch
 180                  * opcode. Just return the target address of the second
 181                  * branch. */
 182                 return pc;
 183         }
 184
 185         /* An opcode located in the delay slot performing a delayed read
 186          * requires special handling; we will always resort to using the
 187          * interpreter in that case.
 188          * Same goes for when we have a branch in a delay slot of another
 189          * branch. */
 190         load_in_ds = opcode_is_load(op->c) || opcode_is_mfc(op->c);
 191         branch_in_ds = has_delay_slot(op->c);
 192
 193         if (branch) {
 194                 if (load_in_ds || branch_in_ds)
 195                         op_next = lightrec_read_opcode(state, pc);
 196
 197                 if (load_in_ds) {
 198                         /* Verify that the next block actually reads the
 199                          * destination register of the delay slot opcode. */
 200                         run_first_op = opcode_reads_register(op_next, op->r.rt);
 201                 }
 202
 203                 if (branch_in_ds) {
 204                         run_first_op = true;
 205                         next_pc = pc + 4;
 206                 }
 207
 208                 if (load_in_ds && run_first_op) {
 209                         next_pc = pc + 4;
 210
 211                         /* If the first opcode of the next block writes the
 212                          * regiser used as the address for the load, we need to
 213                          * reset to the old value after it has been executed,
 214                          * then restore the new value after the delay slot
 215                          * opcode has been executed. */
 216                         save_rs = opcode_reads_register(op->c, op->r.rs) &&
 217                                 opcode_writes_register(op_next, op->r.rs);
 218                         if (save_rs)
 219                                 old_rs = reg_cache[op->r.rs];
 220
 221                         /* If both the first opcode of the next block and the
 222                          * delay slot opcode write to the same register, the
 223                          * value written by the delay slot opcode is
 224                          * discarded. */
 225                         dummy_ld = opcode_writes_register(op_next, op->r.rt);
 226                 }
 227
 228                 if (!run_first_op) {
 229                         next_pc = pc;
 230                 } else if (has_delay_slot(op_next)) {
 231                         /* The first opcode of the next block is a branch, so we
 232                          * cannot execute it here, because of the load delay.
 233                          * Just check whether or not the branch would be taken,
 234                          * and save that info into the interpreter struct. */
 235                         branch_at_addr = true;
 236                         branch_taken = is_branch_taken(reg_cache, op_next);
 237                         pr_debug("Target of impossible branch is a branch, "
 238                                  "%staken.\n", branch_taken ? "" : "not ");
 239                         inter->cycles += lightrec_cycles_of_opcode(inter->state, op_next);
 240                         old_rs = reg_cache[op_next.r.rs];
 241                 } else {
 242                         new_op.c = op_next;
 243                         new_op.flags = 0;
 244                         inter2.op = &new_op;
 245                         inter2.offset = 0;
 246
 247                         /* Execute the first opcode of the next block */
 248                         lightrec_int_op(&inter2);
 249
 250                         if (save_rs) {
 251                                 new_rs = reg_cache[op->r.rs];
 252                                 reg_cache[op->r.rs] = old_rs;
 253                         }
 254
 255                         inter->cycles += lightrec_cycles_of_opcode(inter->state, op_next);
 256                 }
 257         } else {
 258                 next_pc = int_get_ds_pc(inter, 2);
 259         }
 260
 261         inter2.block = inter->block;
 262         inter2.op = op;
 263         inter2.cycles = inter->cycles;
 264         inter2.offset = inter->offset + 1;
 265
 266         if (dummy_ld)
 267                 new_rt = reg_cache[op->r.rt];
 268
 269         /* Execute delay slot opcode */
 270         ds_next_pc = lightrec_int_op(&inter2);
 271
 272         if (branch_at_addr) {
 273                 if (op_next.i.op == OP_SPECIAL)
 274                         /* TODO: Handle JALR setting $ra */
 275                         ds_next_pc = old_rs;
 276                 else if (op_next.i.op == OP_J || op_next.i.op == OP_JAL)
 277                         /* TODO: Handle JAL setting $ra */
 278                         ds_next_pc = (pc & 0xf0000000) | (op_next.j.imm << 2);
 279                 else
 280                         ds_next_pc = pc + 4 + ((s16)op_next.i.imm << 2);
 281         }
 282
 283         if (branch_at_addr && !branch_taken) {
 284                 /* If the branch at the target of the branch opcode is not
 285                  * taken, we jump to its delay slot */
 286                 next_pc = pc + sizeof(u32);
 287         } else if (branch_at_addr || (!branch && branch_in_ds)) {
 288                 next_pc = ds_next_pc;
 289         }
 290
 291         if (save_rs)
 292                 reg_cache[op->r.rs] = new_rs;
 293         if (dummy_ld)
 294                 reg_cache[op->r.rt] = new_rt;
 295
 296         inter->cycles += lightrec_cycles_of_opcode(inter->state, op->c);
 297
 298         if (branch_at_addr && branch_taken) {
 299                 /* If the branch at the target of the branch opcode is taken,
 300                  * we execute its delay slot here, and jump to its target
 301                  * address. */
 302                 op_next = lightrec_read_opcode(state, pc + 4);
 303
 304                 new_op.c = op_next;
 305                 new_op.flags = 0;
 306                 inter2.op = &new_op;
 307                 inter2.block = NULL;
 308
 309                 inter->cycles += lightrec_cycles_of_opcode(inter->state, op_next);
 310
 311                 pr_debug("Running delay slot of branch at target of impossible "
 312                          "branch\n");
 313                 lightrec_int_op(&inter2);
 314         }
 315
 316         return next_pc;
 317 }
 318
 319 static u32 int_unimplemented(struct interpreter *inter)
 320 {
 321         lightrec_set_exit_flags(inter->state, LIGHTREC_EXIT_UNKNOWN_OP);
 322
 323         return inter->block->pc + (inter->offset << 2);
 324 }
 325
 326 static u32 int_jump(struct interpreter *inter, bool link)
 327 {
 328         struct lightrec_state *state = inter->state;
 329         u32 old_pc = int_get_branch_pc(inter);
 330         u32 pc = (old_pc & 0xf0000000) | (inter->op->j.imm << 2);
 331
 332         if (link)
 333                 state->regs.gpr[31] = old_pc + 8;
 334
 335         if (op_flag_no_ds(inter->op->flags))
 336                 return pc;
 337
 338         return int_delay_slot(inter, pc, true);
 339 }
 340
 341 static u32 int_J(struct interpreter *inter)
 342 {
 343         return int_jump(inter, false);
 344 }
 345
 346 static u32 int_JAL(struct interpreter *inter)
 347 {
 348         return int_jump(inter, true);
 349 }
 350
 351 static u32 int_jumpr(struct interpreter *inter, u8 link_reg)
 352 {
 353         struct lightrec_state *state = inter->state;
 354         u32 old_pc = int_get_branch_pc(inter);
 355         u32 next_pc = state->regs.gpr[inter->op->r.rs];
 356
 357         if (link_reg)
 358                 state->regs.gpr[link_reg] = old_pc + 8;
 359
 360         if (op_flag_no_ds(inter->op->flags))
 361                 return next_pc;
 362
 363         return int_delay_slot(inter, next_pc, true);
 364 }
 365
 366 static u32 int_special_JR(struct interpreter *inter)
 367 {
 368         return int_jumpr(inter, 0);
 369 }
 370
 371 static u32 int_special_JALR(struct interpreter *inter)
 372 {
 373         return int_jumpr(inter, inter->op->r.rd);
 374 }
 375
 376 static u32 int_do_branch(struct interpreter *inter, u32 old_pc, u32 next_pc)
 377 {
 378         if (!inter->delay_slot && op_flag_local_branch(inter->op->flags) &&
 379             (s16)inter->op->c.i.imm >= 0) {
 380                 next_pc = old_pc + ((1 + (s16)inter->op->c.i.imm) << 2);
 381                 next_pc = lightrec_emulate_block(inter->state, inter->block, next_pc);
 382         }
 383
 384         return next_pc;
 385 }
 386
 387 static u32 int_branch(struct interpreter *inter, u32 pc,
 388                       union code code, bool branch)
 389 {
 390         u32 next_pc = pc + 4 + ((s16)code.i.imm << 2);
 391
 392         update_cycles_before_branch(inter);
 393
 394         if (op_flag_no_ds(inter->op->flags)) {
 395                 if (branch)
 396                         return int_do_branch(inter, pc, next_pc);
 397                 else
 398                         return jump_next(inter);
 399         }
 400
 401         if (!inter->delay_slot)
 402                 next_pc = int_delay_slot(inter, next_pc, branch);
 403
 404         if (branch)
 405                 return int_do_branch(inter, pc, next_pc);
 406
 407         if (op_flag_emulate_branch(inter->op->flags))
 408                 return pc + 8;
 409         else
 410                 return jump_after_branch(inter);
 411 }
 412
 413 static u32 int_beq(struct interpreter *inter, bool bne)
 414 {
 415         u32 rs, rt, old_pc = int_get_branch_pc(inter);
 416
 417         rs = inter->state->regs.gpr[inter->op->i.rs];
 418         rt = inter->state->regs.gpr[inter->op->i.rt];
 419
 420         return int_branch(inter, old_pc, inter->op->c, (rs == rt) ^ bne);
 421 }
 422
 423 static u32 int_BEQ(struct interpreter *inter)
 424 {
 425         return int_beq(inter, false);
 426 }
 427
 428 static u32 int_BNE(struct interpreter *inter)
 429 {
 430         return int_beq(inter, true);
 431 }
 432
 433 static u32 int_bgez(struct interpreter *inter, bool link, bool lt, bool regimm)
 434 {
 435         u32 old_pc = int_get_branch_pc(inter);
 436         s32 rs;
 437
 438         if (link)
 439                 inter->state->regs.gpr[31] = old_pc + 8;
 440
 441         rs = (s32)inter->state->regs.gpr[inter->op->i.rs];
 442
 443         return int_branch(inter, old_pc, inter->op->c,
 444                           ((regimm && !rs) || rs > 0) ^ lt);
 445 }
 446
 447 static u32 int_regimm_BLTZ(struct interpreter *inter)
 448 {
 449         return int_bgez(inter, false, true, true);
 450 }
 451
 452 static u32 int_regimm_BGEZ(struct interpreter *inter)
 453 {
 454         return int_bgez(inter, false, false, true);
 455 }
 456
 457 static u32 int_regimm_BLTZAL(struct interpreter *inter)
 458 {
 459         return int_bgez(inter, true, true, true);
 460 }
 461
 462 static u32 int_regimm_BGEZAL(struct interpreter *inter)
 463 {
 464         return int_bgez(inter, true, false, true);
 465 }
 466
 467 static u32 int_BLEZ(struct interpreter *inter)
 468 {
 469         return int_bgez(inter, false, true, false);
 470 }
 471
 472 static u32 int_BGTZ(struct interpreter *inter)
 473 {
 474         return int_bgez(inter, false, false, false);
 475 }
 476
 477 static u32 int_cfc(struct interpreter *inter)
 478 {
 479         struct lightrec_state *state = inter->state;
 480         const struct opcode *op = inter->op;
 481         u32 val;
 482
 483         val = lightrec_mfc(state, op->c);
 484
 485         if (likely(op->r.rt))
 486                 state->regs.gpr[op->r.rt] = val;
 487
 488         return jump_next(inter);
 489 }
 490
 491 static u32 int_ctc(struct interpreter *inter)
 492 {
 493         struct lightrec_state *state = inter->state;
 494         const struct opcode *op = inter->op;
 495
 496         lightrec_mtc(state, op->c, op->r.rd, state->regs.gpr[op->r.rt]);
 497
 498         /* If we have a MTC0 or CTC0 to CP0 register 12 (Status) or 13 (Cause),
 499          * return early so that the emulator will be able to check software
 500          * interrupt status. */
 501         if (!op_flag_no_ds(inter->op->flags) &&
 502             op->i.op == OP_CP0 && (op->r.rd == 12 || op->r.rd == 13))
 503                 return int_get_ds_pc(inter, 1);
 504         else
 505                 return jump_next(inter);
 506 }
 507
 508 static u32 int_cp0_RFE(struct interpreter *inter)
 509 {
 510         lightrec_rfe(inter->state);
 511
 512         return jump_next(inter);
 513 }
 514
 515 static u32 int_CP(struct interpreter *inter)
 516 {
 517         lightrec_cp(inter->state, inter->op->c);
 518
 519         return jump_next(inter);
 520 }
 521
 522 static u32 int_ADDI(struct interpreter *inter)
 523 {
 524         u32 *reg_cache = inter->state->regs.gpr;
 525         struct opcode_i *op = &inter->op->i;
 526
 527         if (likely(op->rt))
 528                 reg_cache[op->rt] = reg_cache[op->rs] + (s32)(s16)op->imm;
 529
 530         return jump_next(inter);
 531 }
 532
 533 static u32 int_SLTI(struct interpreter *inter)
 534 {
 535         u32 *reg_cache = inter->state->regs.gpr;
 536         struct opcode_i *op = &inter->op->i;
 537
 538         if (likely(op->rt))
 539                 reg_cache[op->rt] = (s32)reg_cache[op->rs] < (s32)(s16)op->imm;
 540
 541         return jump_next(inter);
 542 }
 543
 544 static u32 int_SLTIU(struct interpreter *inter)
 545 {
 546         u32 *reg_cache = inter->state->regs.gpr;
 547         struct opcode_i *op = &inter->op->i;
 548
 549         if (likely(op->rt))
 550                 reg_cache[op->rt] = reg_cache[op->rs] < (u32)(s32)(s16)op->imm;
 551
 552         return jump_next(inter);
 553 }
 554
 555 static u32 int_ANDI(struct interpreter *inter)
 556 {
 557         u32 *reg_cache = inter->state->regs.gpr;
 558         struct opcode_i *op = &inter->op->i;
 559
 560         if (likely(op->rt))
 561                 reg_cache[op->rt] = reg_cache[op->rs] & op->imm;
 562
 563         return jump_next(inter);
 564 }
 565
 566 static u32 int_ORI(struct interpreter *inter)
 567 {
 568         u32 *reg_cache = inter->state->regs.gpr;
 569         struct opcode_i *op = &inter->op->i;
 570
 571         if (likely(op->rt))
 572                 reg_cache[op->rt] = reg_cache[op->rs] | op->imm;
 573
 574         return jump_next(inter);
 575 }
 576
 577 static u32 int_XORI(struct interpreter *inter)
 578 {
 579         u32 *reg_cache = inter->state->regs.gpr;
 580         struct opcode_i *op = &inter->op->i;
 581
 582         if (likely(op->rt))
 583                 reg_cache[op->rt] = reg_cache[op->rs] ^ op->imm;
 584
 585         return jump_next(inter);
 586 }
 587
 588 static u32 int_LUI(struct interpreter *inter)
 589 {
 590         struct opcode_i *op = &inter->op->i;
 591
 592         inter->state->regs.gpr[op->rt] = op->imm << 16;
 593
 594         return jump_next(inter);
 595 }
 596
 597 static u32 int_io(struct interpreter *inter, bool is_load)
 598 {
 599         struct opcode_i *op = &inter->op->i;
 600         u32 *reg_cache = inter->state->regs.gpr;
 601         u32 val, *flags = NULL;
 602
 603         if (inter->block)
 604                 flags = &inter->op->flags;
 605
 606         val = lightrec_rw(inter->state, inter->op->c,
 607                           reg_cache[op->rs], reg_cache[op->rt],
 608                           flags, inter->block, inter->offset);
 609
 610         if (is_load && op->rt)
 611                 reg_cache[op->rt] = val;
 612
 613         return jump_next(inter);
 614 }
 615
 616 static u32 int_load(struct interpreter *inter)
 617 {
 618         return int_io(inter, true);
 619 }
 620
 621 static u32 int_store(struct interpreter *inter)
 622 {
 623         u32 next_pc;
 624
 625         if (likely(!op_flag_smc(inter->op->flags)))
 626                 return int_io(inter, false);
 627
 628         lightrec_rw(inter->state, inter->op->c,
 629                     inter->state->regs.gpr[inter->op->i.rs],
 630                     inter->state->regs.gpr[inter->op->i.rt],
 631                     &inter->op->flags, inter->block, inter->offset);
 632
 633         next_pc = int_get_ds_pc(inter, 1);
 634
 635         /* Invalidate next PC, to force the rest of the block to be rebuilt */
 636         lightrec_invalidate(inter->state, next_pc, 4);
 637
 638         return next_pc;
 639 }
 640
 641 static u32 int_LWC2(struct interpreter *inter)
 642 {
 643         return int_io(inter, false);
 644 }
 645
 646 static u32 int_special_SLL(struct interpreter *inter)
 647 {
 648         struct opcode *op = inter->op;
 649         u32 rt;
 650
 651         if (op->opcode) { /* Handle NOPs */
 652                 rt = inter->state->regs.gpr[op->r.rt];
 653                 inter->state->regs.gpr[op->r.rd] = rt << op->r.imm;
 654         }
 655
 656         return jump_next(inter);
 657 }
 658
 659 static u32 int_special_SRL(struct interpreter *inter)
 660 {
 661         struct opcode *op = inter->op;
 662         u32 rt = inter->state->regs.gpr[op->r.rt];
 663
 664         inter->state->regs.gpr[op->r.rd] = rt >> op->r.imm;
 665
 666         return jump_next(inter);
 667 }
 668
 669 static u32 int_special_SRA(struct interpreter *inter)
 670 {
 671         struct opcode *op = inter->op;
 672         s32 rt = inter->state->regs.gpr[op->r.rt];
 673
 674         inter->state->regs.gpr[op->r.rd] = rt >> op->r.imm;
 675
 676         return jump_next(inter);
 677 }
 678
 679 static u32 int_special_SLLV(struct interpreter *inter)
 680 {
 681         struct opcode *op = inter->op;
 682         u32 rs = inter->state->regs.gpr[op->r.rs];
 683         u32 rt = inter->state->regs.gpr[op->r.rt];
 684
 685         inter->state->regs.gpr[op->r.rd] = rt << (rs & 0x1f);
 686
 687         return jump_next(inter);
 688 }
 689
 690 static u32 int_special_SRLV(struct interpreter *inter)
 691 {
 692         struct opcode *op = inter->op;
 693         u32 rs = inter->state->regs.gpr[op->r.rs];
 694         u32 rt = inter->state->regs.gpr[op->r.rt];
 695
 696         inter->state->regs.gpr[op->r.rd] = rt >> (rs & 0x1f);
 697
 698         return jump_next(inter);
 699 }
 700
 701 static u32 int_special_SRAV(struct interpreter *inter)
 702 {
 703         struct opcode *op = inter->op;
 704         u32 rs = inter->state->regs.gpr[op->r.rs];
 705         s32 rt = inter->state->regs.gpr[op->r.rt];
 706
 707         inter->state->regs.gpr[op->r.rd] = rt >> (rs & 0x1f);
 708
 709         return jump_next(inter);
 710 }
 711
 712 static u32 int_syscall_break(struct interpreter *inter)
 713 {
 714
 715         if (inter->op->r.op == OP_SPECIAL_BREAK)
 716                 lightrec_set_exit_flags(inter->state, LIGHTREC_EXIT_BREAK);
 717         else
 718                 lightrec_set_exit_flags(inter->state, LIGHTREC_EXIT_SYSCALL);
 719
 720         return int_get_ds_pc(inter, 0);
 721 }
 722
 723 static u32 int_special_MFHI(struct interpreter *inter)
 724 {
 725         u32 *reg_cache = inter->state->regs.gpr;
 726         struct opcode_r *op = &inter->op->r;
 727
 728         if (likely(op->rd))
 729                 reg_cache[op->rd] = reg_cache[REG_HI];
 730
 731         return jump_next(inter);
 732 }
 733
 734 static u32 int_special_MTHI(struct interpreter *inter)
 735 {
 736         u32 *reg_cache = inter->state->regs.gpr;
 737
 738         reg_cache[REG_HI] = reg_cache[inter->op->r.rs];
 739
 740         return jump_next(inter);
 741 }
 742
 743 static u32 int_special_MFLO(struct interpreter *inter)
 744 {
 745         u32 *reg_cache = inter->state->regs.gpr;
 746         struct opcode_r *op = &inter->op->r;
 747
 748         if (likely(op->rd))
 749                 reg_cache[op->rd] = reg_cache[REG_LO];
 750
 751         return jump_next(inter);
 752 }
 753
 754 static u32 int_special_MTLO(struct interpreter *inter)
 755 {
 756         u32 *reg_cache = inter->state->regs.gpr;
 757
 758         reg_cache[REG_LO] = reg_cache[inter->op->r.rs];
 759
 760         return jump_next(inter);
 761 }
 762
 763 static u32 int_special_MULT(struct interpreter *inter)
 764 {
 765         u32 *reg_cache = inter->state->regs.gpr;
 766         s32 rs = reg_cache[inter->op->r.rs];
 767         s32 rt = reg_cache[inter->op->r.rt];
 768         u8 reg_lo = get_mult_div_lo(inter->op->c);
 769         u8 reg_hi = get_mult_div_hi(inter->op->c);
 770         u64 res = (s64)rs * (s64)rt;
 771
 772         if (!op_flag_no_hi(inter->op->flags))
 773                 reg_cache[reg_hi] = res >> 32;
 774         if (!op_flag_no_lo(inter->op->flags))
 775                 reg_cache[reg_lo] = res;
 776
 777         return jump_next(inter);
 778 }
 779
 780 static u32 int_special_MULTU(struct interpreter *inter)
 781 {
 782         u32 *reg_cache = inter->state->regs.gpr;
 783         u32 rs = reg_cache[inter->op->r.rs];
 784         u32 rt = reg_cache[inter->op->r.rt];
 785         u8 reg_lo = get_mult_div_lo(inter->op->c);
 786         u8 reg_hi = get_mult_div_hi(inter->op->c);
 787         u64 res = (u64)rs * (u64)rt;
 788
 789         if (!op_flag_no_hi(inter->op->flags))
 790                 reg_cache[reg_hi] = res >> 32;
 791         if (!op_flag_no_lo(inter->op->flags))
 792                 reg_cache[reg_lo] = res;
 793
 794         return jump_next(inter);
 795 }
 796
 797 static u32 int_special_DIV(struct interpreter *inter)
 798 {
 799         u32 *reg_cache = inter->state->regs.gpr;
 800         s32 rs = reg_cache[inter->op->r.rs];
 801         s32 rt = reg_cache[inter->op->r.rt];
 802         u8 reg_lo = get_mult_div_lo(inter->op->c);
 803         u8 reg_hi = get_mult_div_hi(inter->op->c);
 804         u32 lo, hi;
 805
 806         if (rt == 0) {
 807                 hi = rs;
 808                 lo = (rs < 0) * 2 - 1;
 809         } else {
 810                 lo = rs / rt;
 811                 hi = rs % rt;
 812         }
 813
 814         if (!op_flag_no_hi(inter->op->flags))
 815                 reg_cache[reg_hi] = hi;
 816         if (!op_flag_no_lo(inter->op->flags))
 817                 reg_cache[reg_lo] = lo;
 818
 819         return jump_next(inter);
 820 }
 821
 822 static u32 int_special_DIVU(struct interpreter *inter)
 823 {
 824         u32 *reg_cache = inter->state->regs.gpr;
 825         u32 rs = reg_cache[inter->op->r.rs];
 826         u32 rt = reg_cache[inter->op->r.rt];
 827         u8 reg_lo = get_mult_div_lo(inter->op->c);
 828         u8 reg_hi = get_mult_div_hi(inter->op->c);
 829         u32 lo, hi;
 830
 831         if (rt == 0) {
 832                 hi = rs;
 833                 lo = (u32)-1;
 834         } else {
 835                 lo = rs / rt;
 836                 hi = rs % rt;
 837         }
 838
 839         if (!op_flag_no_hi(inter->op->flags))
 840                 reg_cache[reg_hi] = hi;
 841         if (!op_flag_no_lo(inter->op->flags))
 842                 reg_cache[reg_lo] = lo;
 843
 844         return jump_next(inter);
 845 }
 846
 847 static u32 int_special_ADD(struct interpreter *inter)
 848 {
 849         u32 *reg_cache = inter->state->regs.gpr;
 850         struct opcode_r *op = &inter->op->r;
 851         s32 rs = reg_cache[op->rs];
 852         s32 rt = reg_cache[op->rt];
 853
 854         if (likely(op->rd))
 855                 reg_cache[op->rd] = rs + rt;
 856
 857         return jump_next(inter);
 858 }
 859
 860 static u32 int_special_SUB(struct interpreter *inter)
 861 {
 862         u32 *reg_cache = inter->state->regs.gpr;
 863         struct opcode_r *op = &inter->op->r;
 864         u32 rs = reg_cache[op->rs];
 865         u32 rt = reg_cache[op->rt];
 866
 867         if (likely(op->rd))
 868                 reg_cache[op->rd] = rs - rt;
 869
 870         return jump_next(inter);
 871 }
 872
 873 static u32 int_special_AND(struct interpreter *inter)
 874 {
 875         u32 *reg_cache = inter->state->regs.gpr;
 876         struct opcode_r *op = &inter->op->r;
 877         u32 rs = reg_cache[op->rs];
 878         u32 rt = reg_cache[op->rt];
 879
 880         if (likely(op->rd))
 881                 reg_cache[op->rd] = rs & rt;
 882
 883         return jump_next(inter);
 884 }
 885
 886 static u32 int_special_OR(struct interpreter *inter)
 887 {
 888         u32 *reg_cache = inter->state->regs.gpr;
 889         struct opcode_r *op = &inter->op->r;
 890         u32 rs = reg_cache[op->rs];
 891         u32 rt = reg_cache[op->rt];
 892
 893         if (likely(op->rd))
 894                 reg_cache[op->rd] = rs | rt;
 895
 896         return jump_next(inter);
 897 }
 898
 899 static u32 int_special_XOR(struct interpreter *inter)
 900 {
 901         u32 *reg_cache = inter->state->regs.gpr;
 902         struct opcode_r *op = &inter->op->r;
 903         u32 rs = reg_cache[op->rs];
 904         u32 rt = reg_cache[op->rt];
 905
 906         if (likely(op->rd))
 907                 reg_cache[op->rd] = rs ^ rt;
 908
 909         return jump_next(inter);
 910 }
 911
 912 static u32 int_special_NOR(struct interpreter *inter)
 913 {
 914         u32 *reg_cache = inter->state->regs.gpr;
 915         struct opcode_r *op = &inter->op->r;
 916         u32 rs = reg_cache[op->rs];
 917         u32 rt = reg_cache[op->rt];
 918
 919         if (likely(op->rd))
 920                 reg_cache[op->rd] = ~(rs | rt);
 921
 922         return jump_next(inter);
 923 }
 924
 925 static u32 int_special_SLT(struct interpreter *inter)
 926 {
 927         u32 *reg_cache = inter->state->regs.gpr;
 928         struct opcode_r *op = &inter->op->r;
 929         s32 rs = reg_cache[op->rs];
 930         s32 rt = reg_cache[op->rt];
 931
 932         if (likely(op->rd))
 933                 reg_cache[op->rd] = rs < rt;
 934
 935         return jump_next(inter);
 936 }
 937
 938 static u32 int_special_SLTU(struct interpreter *inter)
 939 {
 940         u32 *reg_cache = inter->state->regs.gpr;
 941         struct opcode_r *op = &inter->op->r;
 942         u32 rs = reg_cache[op->rs];
 943         u32 rt = reg_cache[op->rt];
 944
 945         if (likely(op->rd))
 946                 reg_cache[op->rd] = rs < rt;
 947
 948         return jump_next(inter);
 949 }
 950
 951 static u32 int_META_MOV(struct interpreter *inter)
 952 {
 953         u32 *reg_cache = inter->state->regs.gpr;
 954         struct opcode_m *op = &inter->op->m;
 955
 956         if (likely(op->rd))
 957                 reg_cache[op->rd] = reg_cache[op->rs];
 958
 959         return jump_next(inter);
 960 }
 961
 962 static u32 int_META_EXTC(struct interpreter *inter)
 963 {
 964         u32 *reg_cache = inter->state->regs.gpr;
 965         struct opcode_m *op = &inter->op->m;
 966
 967         if (likely(op->rd))
 968                 reg_cache[op->rd] = (u32)(s32)(s8)reg_cache[op->rs];
 969
 970         return jump_next(inter);
 971 }
 972
 973 static u32 int_META_EXTS(struct interpreter *inter)
 974 {
 975         u32 *reg_cache = inter->state->regs.gpr;
 976         struct opcode_m *op = &inter->op->m;
 977
 978         if (likely(op->rd))
 979                 reg_cache[op->rd] = (u32)(s32)(s16)reg_cache[op->rs];
 980
 981         return jump_next(inter);
 982 }
 983
 984 static u32 int_META_MULT2(struct interpreter *inter)
 985 {
 986         u32 *reg_cache = inter->state->regs.gpr;
 987         union code c = inter->op->c;
 988         u32 rs = reg_cache[c.r.rs];
 989         u8 reg_lo = get_mult_div_lo(c);
 990         u8 reg_hi = get_mult_div_hi(c);
 991
 992         if (!op_flag_no_lo(inter->op->flags)) {
 993                 if (c.r.op < 32)
 994                         reg_cache[reg_lo] = rs << c.r.op;
 995                 else
 996                         reg_cache[reg_lo] = 0;
 997         }
 998
 999         if (!op_flag_no_hi(inter->op->flags)) {
1000                 if (c.r.op >= 32)
1001                         reg_cache[reg_hi] = rs << (c.r.op - 32);
1002                 else if (c.i.op == OP_META_MULT2)
1003                         reg_cache[reg_hi] = (s32) rs >> (32 - c.r.op);
1004                 else
1005                         reg_cache[reg_hi] = rs >> (32 - c.r.op);
1006         }
1007
1008         return jump_next(inter);
1009 }
1010
1011 static u32 int_META_COM(struct interpreter *inter)
1012 {
1013         u32 *reg_cache = inter->state->regs.gpr;
1014         union code c = inter->op->c;
1015
1016         if (likely(c.m.rd))
1017                 reg_cache[c.m.rd] = ~reg_cache[c.m.rs];
1018
1019         return jump_next(inter);
1020 }
1021
1022 static const lightrec_int_func_t int_standard[64] = {
1023         SET_DEFAULT_ELM(int_standard, int_unimplemented),
1024         [OP_SPECIAL]            = int_SPECIAL,
1025         [OP_REGIMM]             = int_REGIMM,
1026         [OP_J]                  = int_J,
1027         [OP_JAL]                = int_JAL,
1028         [OP_BEQ]                = int_BEQ,
1029         [OP_BNE]                = int_BNE,
1030         [OP_BLEZ]               = int_BLEZ,
1031         [OP_BGTZ]               = int_BGTZ,
1032         [OP_ADDI]               = int_ADDI,
1033         [OP_ADDIU]              = int_ADDI,
1034         [OP_SLTI]               = int_SLTI,
1035         [OP_SLTIU]              = int_SLTIU,
1036         [OP_ANDI]               = int_ANDI,
1037         [OP_ORI]                = int_ORI,
1038         [OP_XORI]               = int_XORI,
1039         [OP_LUI]                = int_LUI,
1040         [OP_CP0]                = int_CP0,
1041         [OP_CP2]                = int_CP2,
1042         [OP_LB]                 = int_load,
1043         [OP_LH]                 = int_load,
1044         [OP_LWL]                = int_load,
1045         [OP_LW]                 = int_load,
1046         [OP_LBU]                = int_load,
1047         [OP_LHU]                = int_load,
1048         [OP_LWR]                = int_load,
1049         [OP_SB]                 = int_store,
1050         [OP_SH]                 = int_store,
1051         [OP_SWL]                = int_store,
1052         [OP_SW]                 = int_store,
1053         [OP_SWR]                = int_store,
1054         [OP_LWC2]               = int_LWC2,
1055         [OP_SWC2]               = int_store,
1056
1057         [OP_META]               = int_META,
1058         [OP_META_MULT2]         = int_META_MULT2,
1059         [OP_META_MULTU2]        = int_META_MULT2,
1060 };
1061
1062 static const lightrec_int_func_t int_special[64] = {
1063         SET_DEFAULT_ELM(int_special, int_unimplemented),
1064         [OP_SPECIAL_SLL]        = int_special_SLL,
1065         [OP_SPECIAL_SRL]        = int_special_SRL,
1066         [OP_SPECIAL_SRA]        = int_special_SRA,
1067         [OP_SPECIAL_SLLV]       = int_special_SLLV,
1068         [OP_SPECIAL_SRLV]       = int_special_SRLV,
1069         [OP_SPECIAL_SRAV]       = int_special_SRAV,
1070         [OP_SPECIAL_JR]         = int_special_JR,
1071         [OP_SPECIAL_JALR]       = int_special_JALR,
1072         [OP_SPECIAL_SYSCALL]    = int_syscall_break,
1073         [OP_SPECIAL_BREAK]      = int_syscall_break,
1074         [OP_SPECIAL_MFHI]       = int_special_MFHI,
1075         [OP_SPECIAL_MTHI]       = int_special_MTHI,
1076         [OP_SPECIAL_MFLO]       = int_special_MFLO,
1077         [OP_SPECIAL_MTLO]       = int_special_MTLO,
1078         [OP_SPECIAL_MULT]       = int_special_MULT,
1079         [OP_SPECIAL_MULTU]      = int_special_MULTU,
1080         [OP_SPECIAL_DIV]        = int_special_DIV,
1081         [OP_SPECIAL_DIVU]       = int_special_DIVU,
1082         [OP_SPECIAL_ADD]        = int_special_ADD,
1083         [OP_SPECIAL_ADDU]       = int_special_ADD,
1084         [OP_SPECIAL_SUB]        = int_special_SUB,
1085         [OP_SPECIAL_SUBU]       = int_special_SUB,
1086         [OP_SPECIAL_AND]        = int_special_AND,
1087         [OP_SPECIAL_OR]         = int_special_OR,
1088         [OP_SPECIAL_XOR]        = int_special_XOR,
1089         [OP_SPECIAL_NOR]        = int_special_NOR,
1090         [OP_SPECIAL_SLT]        = int_special_SLT,
1091         [OP_SPECIAL_SLTU]       = int_special_SLTU,
1092 };
1093
1094 static const lightrec_int_func_t int_regimm[64] = {
1095         SET_DEFAULT_ELM(int_regimm, int_unimplemented),
1096         [OP_REGIMM_BLTZ]        = int_regimm_BLTZ,
1097         [OP_REGIMM_BGEZ]        = int_regimm_BGEZ,
1098         [OP_REGIMM_BLTZAL]      = int_regimm_BLTZAL,
1099         [OP_REGIMM_BGEZAL]      = int_regimm_BGEZAL,
1100 };
1101
1102 static const lightrec_int_func_t int_cp0[64] = {
1103         SET_DEFAULT_ELM(int_cp0, int_CP),
1104         [OP_CP0_MFC0]           = int_cfc,
1105         [OP_CP0_CFC0]           = int_cfc,
1106         [OP_CP0_MTC0]           = int_ctc,
1107         [OP_CP0_CTC0]           = int_ctc,
1108         [OP_CP0_RFE]            = int_cp0_RFE,
1109 };
1110
1111 static const lightrec_int_func_t int_cp2_basic[64] = {
1112         SET_DEFAULT_ELM(int_cp2_basic, int_CP),
1113         [OP_CP2_BASIC_MFC2]     = int_cfc,
1114         [OP_CP2_BASIC_CFC2]     = int_cfc,
1115         [OP_CP2_BASIC_MTC2]     = int_ctc,
1116         [OP_CP2_BASIC_CTC2]     = int_ctc,
1117 };
1118
1119 static const lightrec_int_func_t int_meta[64] = {
1120         SET_DEFAULT_ELM(int_meta, int_unimplemented),
1121         [OP_META_MOV]           = int_META_MOV,
1122         [OP_META_EXTC]          = int_META_EXTC,
1123         [OP_META_EXTS]          = int_META_EXTS,
1124         [OP_META_COM]           = int_META_COM,
1125 };
1126
1127 static u32 int_SPECIAL(struct interpreter *inter)
1128 {
1129         lightrec_int_func_t f = int_special[inter->op->r.op];
1130
1131         if (!HAS_DEFAULT_ELM && unlikely(!f))
1132                 return int_unimplemented(inter);
1133
1134         return execute(f, inter);
1135 }
1136
1137 static u32 int_REGIMM(struct interpreter *inter)
1138 {
1139         lightrec_int_func_t f = int_regimm[inter->op->r.rt];
1140
1141         if (!HAS_DEFAULT_ELM && unlikely(!f))
1142                 return int_unimplemented(inter);
1143
1144         return execute(f, inter);
1145 }
1146
1147 static u32 int_CP0(struct interpreter *inter)
1148 {
1149         lightrec_int_func_t f = int_cp0[inter->op->r.rs];
1150
1151         if (!HAS_DEFAULT_ELM && unlikely(!f))
1152                 return int_CP(inter);
1153
1154         return execute(f, inter);
1155 }
1156
1157 static u32 int_CP2(struct interpreter *inter)
1158 {
1159         if (inter->op->r.op == OP_CP2_BASIC) {
1160                 lightrec_int_func_t f = int_cp2_basic[inter->op->r.rs];
1161                 if (HAS_DEFAULT_ELM || likely(f))
1162                         return execute(f, inter);
1163         }
1164
1165         return int_CP(inter);
1166 }
1167
1168 static u32 int_META(struct interpreter *inter)
1169 {
1170         lightrec_int_func_t f = int_meta[inter->op->m.op];
1171
1172         if (!HAS_DEFAULT_ELM && unlikely(!f))
1173                 return int_unimplemented(inter);
1174
1175         return execute(f, inter);
1176 }
1177
1178 static u32 lightrec_emulate_block_list(struct lightrec_state *state,
1179                                        struct block *block, u32 offset)
1180 {
1181         struct interpreter inter;
1182         u32 pc;
1183
1184         inter.block = block;
1185         inter.state = state;
1186         inter.offset = offset;
1187         inter.op = &block->opcode_list[offset];
1188         inter.cycles = 0;
1189         inter.delay_slot = false;
1190
1191         pc = lightrec_int_op(&inter);
1192
1193         /* Add the cycles of the last branch */
1194         inter.cycles += lightrec_cycles_of_opcode(inter.state, inter.op->c);
1195
1196         state->current_cycle += inter.cycles;
1197
1198         return pc;
1199 }
1200
1201 u32 lightrec_emulate_block(struct lightrec_state *state, struct block *block, u32 pc)
1202 {
1203         u32 offset = (kunseg(pc) - kunseg(block->pc)) >> 2;
1204
1205         if (offset < block->nb_ops)
1206                 return lightrec_emulate_block_list(state, block, offset);
1207
1208         pr_err("PC 0x%x is outside block at PC 0x%x\n", pc, block->pc);
1209
1210         lightrec_set_exit_flags(state, LIGHTREC_EXIT_SEGFAULT);
1211
1212         return 0;
1213 }
1214
1215 static u32 branch_get_next_pc(struct lightrec_state *state, union code c, u32 pc)
1216 {
1217         switch (c.i.op) {
1218         case OP_SPECIAL:
1219                 /* JR / JALR */
1220                 return state->regs.gpr[c.r.rs];
1221         case OP_J:
1222         case OP_JAL:
1223                 return (pc & 0xf0000000) | (c.j.imm << 2);
1224         default:
1225                 /* Branch opcodes */
1226                 return pc + 4 + ((s16)c.i.imm << 2);
1227         }
1228 }
1229
1230 u32 lightrec_handle_load_delay(struct lightrec_state *state,
1231                                struct block *block, u32 pc, u32 reg)
1232 {
1233         union code c = lightrec_read_opcode(state, pc);
1234         struct opcode op[2] = {
1235                 {
1236                         .c = c,
1237                         .flags = 0,
1238                 },
1239                 {
1240                         .flags = 0,
1241                 },
1242         };
1243         struct interpreter inter = {
1244                 .block = block,
1245                 .state = state,
1246                 .offset = 0,
1247                 .op = op,
1248                 .cycles = 0,
1249         };
1250         bool branch_taken;
1251         u32 reg_mask, next_pc;
1252
1253         if (has_delay_slot(c)) {
1254                 op[1].c = lightrec_read_opcode(state, pc + 4);
1255
1256                 branch_taken = is_branch_taken(state->regs.gpr, c);
1257                 next_pc = branch_get_next_pc(state, c, pc);
1258
1259                 /* Branch was evaluated, we can write the load opcode's target
1260                  * register now. */
1261                 state->regs.gpr[reg] = state->temp_reg;
1262
1263                 /* Handle JALR / regimm opcodes setting $ra (or any other
1264                  * register in the case of JALR) */
1265                 reg_mask = (u32)opcode_write_mask(c);
1266                 if (reg_mask)
1267                         state->regs.gpr[ctz32(reg_mask)] = pc + 8;
1268
1269                 /* Handle delay slot of the branch opcode */
1270                 pc = int_delay_slot(&inter, next_pc, branch_taken);
1271         } else {
1272                 /* Make sure we only run one instruction */
1273                 inter.delay_slot = true;
1274
1275                 lightrec_int_op(&inter);
1276                 pc += 4;
1277
1278                 if (!opcode_writes_register(c, reg))
1279                         state->regs.gpr[reg] = state->temp_reg;
1280         }
1281
1282         state->current_cycle += inter.cycles;
1283
1284         return pc;
1285 }