sim/m68hc11/interp.c

   1 /* interp.c -- Simulator for Motorola 68HC11/68HC12
   2    Copyright (C) 1999-2022 Free Software Foundation, Inc.
   3    Written by Stephane Carrez (stcarrez@nerim.fr)
   4
   5 This file is part of GDB, the GNU debugger.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* This must come before any other includes.  */
  21 #include "defs.h"
  22
  23 #include "bfd.h"
  24
  25 #include "sim-main.h"
  26 #include "sim-assert.h"
  27 #include "sim-hw.h"
  28 #include "sim-options.h"
  29 #include "hw-tree.h"
  30 #include "hw-device.h"
  31 #include "hw-ports.h"
  32 #include "elf32-m68hc1x.h"
  33
  34 #include "m68hc11-sim.h"
  35
  36 #ifndef MONITOR_BASE
  37 # define MONITOR_BASE (0x0C000)
  38 # define MONITOR_SIZE (0x04000)
  39 #endif
  40
  41 static void sim_get_info (SIM_DESC sd, char *cmd);
  42
  43 struct sim_info_list
  44 {
  45   const char *name;
  46   const char *device;
  47 };
  48
  49 struct sim_info_list dev_list_68hc11[] = {
  50   {"cpu", "/m68hc11"},
  51   {"timer", "/m68hc11/m68hc11tim"},
  52   {"sio", "/m68hc11/m68hc11sio"},
  53   {"spi", "/m68hc11/m68hc11spi"},
  54   {"eeprom", "/m68hc11/m68hc11eepr"},
  55   {0, 0}
  56 };
  57
  58 struct sim_info_list dev_list_68hc12[] = {
  59   {"cpu", "/m68hc12"},
  60   {"timer", "/m68hc12/m68hc12tim"},
  61   {"sio", "/m68hc12/m68hc12sio"},
  62   {"spi", "/m68hc12/m68hc12spi"},
  63   {"eeprom", "/m68hc12/m68hc12eepr"},
  64   {0, 0}
  65 };
  66
  67 /* Cover function of sim_state_free to free the cpu buffers as well.  */
  68
  69 static void
  70 free_state (SIM_DESC sd)
  71 {
  72   if (STATE_MODULES (sd) != NULL)
  73     sim_module_uninstall (sd);
  74
  75   sim_state_free (sd);
  76 }
  77
  78 /* Give some information about the simulator.  */
  79 static void
  80 sim_get_info (SIM_DESC sd, char *cmd)
  81 {
  82   sim_cpu *cpu;
  83
  84   cpu = STATE_CPU (sd, 0);
  85   if (cmd != 0 && (cmd[0] == ' ' || cmd[0] == '-'))
  86     {
  87       int i;
  88       struct hw *hw_dev;
  89       struct sim_info_list *dev_list;
  90       const struct bfd_arch_info *arch;
  91
  92       arch = STATE_ARCHITECTURE (sd);
  93       cmd++;
  94
  95       if (arch->arch == bfd_arch_m68hc11)
  96         dev_list = dev_list_68hc11;
  97       else
  98         dev_list = dev_list_68hc12;
  99
 100       for (i = 0; dev_list[i].name; i++)
 101         if (strcmp (cmd, dev_list[i].name) == 0)
 102           break;
 103
 104       if (dev_list[i].name == 0)
 105         {
 106           sim_io_eprintf (sd, "Device '%s' not found.\n", cmd);
 107           sim_io_eprintf (sd, "Valid devices: cpu timer sio eeprom\n");
 108           return;
 109         }
 110       hw_dev = sim_hw_parse (sd, "%s", dev_list[i].device);
 111       if (hw_dev == 0)
 112         {
 113           sim_io_eprintf (sd, "Device '%s' not found\n", dev_list[i].device);
 114           return;
 115         }
 116       hw_ioctl (hw_dev, 23, 0);
 117       return;
 118     }
 119
 120   cpu_info (sd, cpu);
 121   interrupts_info (sd, &M68HC11_SIM_CPU (cpu)->cpu_interrupts);
 122 }
 123
 124
 125 void
 126 sim_board_reset (SIM_DESC sd)
 127 {
 128   struct hw *hw_cpu;
 129   sim_cpu *cpu;
 130   struct m68hc11_sim_cpu *m68hc11_cpu;
 131   const struct bfd_arch_info *arch;
 132   const char *cpu_type;
 133
 134   cpu = STATE_CPU (sd, 0);
 135   m68hc11_cpu = M68HC11_SIM_CPU (cpu);
 136   arch = STATE_ARCHITECTURE (sd);
 137
 138   /*  hw_cpu = sim_hw_parse (sd, "/"); */
 139   if (arch->arch == bfd_arch_m68hc11)
 140     {
 141       m68hc11_cpu->cpu_type = CPU_M6811;
 142       cpu_type = "/m68hc11";
 143     }
 144   else
 145     {
 146       m68hc11_cpu->cpu_type = CPU_M6812;
 147       cpu_type = "/m68hc12";
 148     }
 149
 150   hw_cpu = sim_hw_parse (sd, "%s", cpu_type);
 151   if (hw_cpu == 0)
 152     {
 153       sim_io_eprintf (sd, "%s cpu not found in device tree.", cpu_type);
 154       return;
 155     }
 156
 157   cpu_reset (cpu);
 158   hw_port_event (hw_cpu, 3, 0);
 159   cpu_restart (cpu);
 160 }
 161
 162 static int
 163 sim_hw_configure (SIM_DESC sd)
 164 {
 165   const struct bfd_arch_info *arch;
 166   struct hw *device_tree;
 167   sim_cpu *cpu;
 168   struct m68hc11_sim_cpu *m68hc11_cpu;
 169
 170   arch = STATE_ARCHITECTURE (sd);
 171   if (arch == 0)
 172     return 0;
 173
 174   cpu = STATE_CPU (sd, 0);
 175   m68hc11_cpu = M68HC11_SIM_CPU (cpu);
 176   m68hc11_cpu->cpu_configured_arch = arch;
 177   device_tree = sim_hw_parse (sd, "/");
 178   if (arch->arch == bfd_arch_m68hc11)
 179     {
 180       m68hc11_cpu->cpu_interpretor = cpu_interp_m6811;
 181       if (hw_tree_find_property (device_tree, "/m68hc11/reg") == 0)
 182         {
 183           /* Allocate core managed memory */
 184
 185           /* the monitor  */
 186           sim_do_commandf (sd, "memory region 0x%x@%d,0x%x",
 187                            /* MONITOR_BASE, MONITOR_SIZE */
 188                            0x8000, M6811_RAM_LEVEL, 0x8000);
 189           sim_do_commandf (sd, "memory region 0x000@%d,0x8000",
 190                            M6811_RAM_LEVEL);
 191           sim_hw_parse (sd, "/m68hc11/reg 0x1000 0x03F");
 192           if (m68hc11_cpu->bank_start < m68hc11_cpu->bank_end)
 193             {
 194               sim_do_commandf (sd, "memory region 0x%x@%d,0x100000",
 195                                m68hc11_cpu->bank_virtual, M6811_RAM_LEVEL);
 196               sim_hw_parse (sd, "/m68hc11/use_bank 1");
 197             }
 198         }
 199       if (m68hc11_cpu->cpu_start_mode)
 200         {
 201           sim_hw_parse (sd, "/m68hc11/mode %s", m68hc11_cpu->cpu_start_mode);
 202         }
 203       if (hw_tree_find_property (device_tree, "/m68hc11/m68hc11sio/reg") == 0)
 204         {
 205           sim_hw_parse (sd, "/m68hc11/m68hc11sio/reg 0x2b 0x5");
 206           sim_hw_parse (sd, "/m68hc11/m68hc11sio/backend stdio");
 207           sim_hw_parse (sd, "/m68hc11 > cpu-reset reset /m68hc11/m68hc11sio");
 208         }
 209       if (hw_tree_find_property (device_tree, "/m68hc11/m68hc11tim/reg") == 0)
 210         {
 211           /* M68hc11 Timer configuration. */
 212           sim_hw_parse (sd, "/m68hc11/m68hc11tim/reg 0x1b 0x5");
 213           sim_hw_parse (sd, "/m68hc11 > cpu-reset reset /m68hc11/m68hc11tim");
 214           sim_hw_parse (sd, "/m68hc11 > capture capture /m68hc11/m68hc11tim");
 215         }
 216
 217       /* Create the SPI device.  */
 218       if (hw_tree_find_property (device_tree, "/m68hc11/m68hc11spi/reg") == 0)
 219         {
 220           sim_hw_parse (sd, "/m68hc11/m68hc11spi/reg 0x28 0x3");
 221           sim_hw_parse (sd, "/m68hc11 > cpu-reset reset /m68hc11/m68hc11spi");
 222         }
 223       if (hw_tree_find_property (device_tree, "/m68hc11/nvram/reg") == 0)
 224         {
 225           /* M68hc11 persistent ram configuration. */
 226           sim_hw_parse (sd, "/m68hc11/nvram/reg 0x0 256");
 227           sim_hw_parse (sd, "/m68hc11/nvram/file m68hc11.ram");
 228           sim_hw_parse (sd, "/m68hc11/nvram/mode save-modified");
 229           /*sim_hw_parse (sd, "/m68hc11 > cpu-reset reset /m68hc11/pram"); */
 230         }
 231       if (hw_tree_find_property (device_tree, "/m68hc11/m68hc11eepr/reg") == 0)
 232         {
 233           sim_hw_parse (sd, "/m68hc11/m68hc11eepr/reg 0xb000 512");
 234           sim_hw_parse (sd, "/m68hc11 > cpu-reset reset /m68hc11/m68hc11eepr");
 235         }
 236       sim_hw_parse (sd, "/m68hc11 > port-a cpu-write-port /m68hc11");
 237       sim_hw_parse (sd, "/m68hc11 > port-b cpu-write-port /m68hc11");
 238       sim_hw_parse (sd, "/m68hc11 > port-c cpu-write-port /m68hc11");
 239       sim_hw_parse (sd, "/m68hc11 > port-d cpu-write-port /m68hc11");
 240       m68hc11_cpu->hw_cpu = sim_hw_parse (sd, "/m68hc11");
 241     }
 242   else
 243     {
 244       m68hc11_cpu->cpu_interpretor = cpu_interp_m6812;
 245       if (hw_tree_find_property (device_tree, "/m68hc12/reg") == 0)
 246         {
 247           /* Allocate core external memory.  */
 248           sim_do_commandf (sd, "memory region 0x%x@%d,0x%x",
 249                            0x8000, M6811_RAM_LEVEL, 0x8000);
 250           sim_do_commandf (sd, "memory region 0x000@%d,0x8000",
 251                            M6811_RAM_LEVEL);
 252           if (m68hc11_cpu->bank_start < m68hc11_cpu->bank_end)
 253             {
 254               sim_do_commandf (sd, "memory region 0x%x@%d,0x100000",
 255                                m68hc11_cpu->bank_virtual, M6811_RAM_LEVEL);
 256               sim_hw_parse (sd, "/m68hc12/use_bank 1");
 257             }
 258           sim_hw_parse (sd, "/m68hc12/reg 0x0 0x3FF");
 259         }
 260
 261       if (!hw_tree_find_property (device_tree, "/m68hc12/m68hc12sio@1/reg"))
 262         {
 263           sim_hw_parse (sd, "/m68hc12/m68hc12sio@1/reg 0xC0 0x8");
 264           sim_hw_parse (sd, "/m68hc12/m68hc12sio@1/backend stdio");
 265           sim_hw_parse (sd, "/m68hc12 > cpu-reset reset /m68hc12/m68hc12sio@1");
 266         }
 267       if (hw_tree_find_property (device_tree, "/m68hc12/m68hc12tim/reg") == 0)
 268         {
 269           /* M68hc11 Timer configuration. */
 270           sim_hw_parse (sd, "/m68hc12/m68hc12tim/reg 0x1b 0x5");
 271           sim_hw_parse (sd, "/m68hc12 > cpu-reset reset /m68hc12/m68hc12tim");
 272           sim_hw_parse (sd, "/m68hc12 > capture capture /m68hc12/m68hc12tim");
 273         }
 274
 275       /* Create the SPI device.  */
 276       if (hw_tree_find_property (device_tree, "/m68hc12/m68hc12spi/reg") == 0)
 277         {
 278           sim_hw_parse (sd, "/m68hc12/m68hc12spi/reg 0x28 0x3");
 279           sim_hw_parse (sd, "/m68hc12 > cpu-reset reset /m68hc12/m68hc12spi");
 280         }
 281       if (hw_tree_find_property (device_tree, "/m68hc12/nvram/reg") == 0)
 282         {
 283           /* M68hc11 persistent ram configuration. */
 284           sim_hw_parse (sd, "/m68hc12/nvram/reg 0x2000 8192");
 285           sim_hw_parse (sd, "/m68hc12/nvram/file m68hc12.ram");
 286           sim_hw_parse (sd, "/m68hc12/nvram/mode save-modified");
 287         }
 288       if (hw_tree_find_property (device_tree, "/m68hc12/m68hc12eepr/reg") == 0)
 289         {
 290           sim_hw_parse (sd, "/m68hc12/m68hc12eepr/reg 0x0800 2048");
 291           sim_hw_parse (sd, "/m68hc12 > cpu-reset reset /m68hc12/m68hc12eepr");
 292         }
 293
 294       sim_hw_parse (sd, "/m68hc12 > port-a cpu-write-port /m68hc12");
 295       sim_hw_parse (sd, "/m68hc12 > port-b cpu-write-port /m68hc12");
 296       sim_hw_parse (sd, "/m68hc12 > port-c cpu-write-port /m68hc12");
 297       sim_hw_parse (sd, "/m68hc12 > port-d cpu-write-port /m68hc12");
 298       m68hc11_cpu->hw_cpu = sim_hw_parse (sd, "/m68hc12");
 299     }
 300   return 1;
 301 }
 302
 303 /* Get the memory bank parameters by looking at the global symbols
 304    defined by the linker.  */
 305 static int
 306 sim_get_bank_parameters (SIM_DESC sd)
 307 {
 308   sim_cpu *cpu;
 309   struct m68hc11_sim_cpu *m68hc11_cpu;
 310   unsigned size;
 311   bfd_vma addr;
 312
 313   cpu = STATE_CPU (sd, 0);
 314   m68hc11_cpu = M68HC11_SIM_CPU (cpu);
 315
 316   addr = trace_sym_value (sd, BFD_M68HC11_BANK_START_NAME);
 317   if (addr != -1)
 318     m68hc11_cpu->bank_start = addr;
 319
 320   size = trace_sym_value (sd, BFD_M68HC11_BANK_SIZE_NAME);
 321   if (size == -1)
 322     size = 0;
 323
 324   addr = trace_sym_value (sd, BFD_M68HC11_BANK_VIRTUAL_NAME);
 325   if (addr != -1)
 326     m68hc11_cpu->bank_virtual = addr;
 327
 328   m68hc11_cpu->bank_end = m68hc11_cpu->bank_start + size;
 329   m68hc11_cpu->bank_shift = 0;
 330   for (; size > 1; size >>= 1)
 331     m68hc11_cpu->bank_shift++;
 332
 333   return 0;
 334 }
 335
 336 static int
 337 sim_prepare_for_program (SIM_DESC sd, bfd* abfd)
 338 {
 339   sim_cpu *cpu;
 340   struct m68hc11_sim_cpu *m68hc11_cpu;
 341   int elf_flags = 0;
 342
 343   cpu = STATE_CPU (sd, 0);
 344   m68hc11_cpu = M68HC11_SIM_CPU (cpu);
 345
 346   if (abfd != NULL)
 347     {
 348       asection *s;
 349
 350       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 351         elf_flags = elf_elfheader (abfd)->e_flags;
 352
 353       m68hc11_cpu->cpu_elf_start = bfd_get_start_address (abfd);
 354       /* See if any section sets the reset address */
 355       m68hc11_cpu->cpu_use_elf_start = 1;
 356       for (s = abfd->sections; s && m68hc11_cpu->cpu_use_elf_start; s = s->next)
 357         {
 358           if (s->flags & SEC_LOAD)
 359             {
 360               bfd_size_type size;
 361
 362               size = bfd_section_size (s);
 363               if (size > 0)
 364                 {
 365                   bfd_vma lma;
 366
 367                   if (STATE_LOAD_AT_LMA_P (sd))
 368                     lma = bfd_section_lma (s);
 369                   else
 370                     lma = bfd_section_vma (s);
 371
 372                   if (lma <= 0xFFFE && lma+size >= 0x10000)
 373                     m68hc11_cpu->cpu_use_elf_start = 0;
 374                 }
 375             }
 376         }
 377
 378       if (elf_flags & E_M68HC12_BANKS)
 379         {
 380           if (sim_get_bank_parameters (sd) != 0)
 381             sim_io_eprintf (sd, "Memory bank parameters are not initialized\n");
 382         }
 383     }
 384
 385   if (!sim_hw_configure (sd))
 386     return SIM_RC_FAIL;
 387
 388   /* reset all state information */
 389   sim_board_reset (sd);
 390
 391   return SIM_RC_OK;
 392 }
 393
 394 static sim_cia
 395 m68hc11_pc_get (sim_cpu *cpu)
 396 {
 397   return cpu_get_pc (cpu);
 398 }
 399
 400 static void
 401 m68hc11_pc_set (sim_cpu *cpu, sim_cia pc)
 402 {
 403   cpu_set_pc (cpu, pc);
 404 }
 405
 406 static int m68hc11_reg_fetch (SIM_CPU *, int, void *, int);
 407 static int m68hc11_reg_store (SIM_CPU *, int, const void *, int);
 408
 409 SIM_DESC
 410 sim_open (SIM_OPEN_KIND kind, host_callback *callback,
 411           bfd *abfd, char * const *argv)
 412 {
 413   int i;
 414   SIM_DESC sd;
 415   sim_cpu *cpu;
 416
 417   sd = sim_state_alloc (kind, callback);
 418
 419   SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
 420
 421   /* Set default options before parsing user options.  */
 422   current_target_byte_order = BFD_ENDIAN_BIG;
 423
 424   /* The cpu data is kept in a separately allocated chunk of memory.  */
 425   if (sim_cpu_alloc_all_extra (sd, 0, sizeof (struct m68hc11_sim_cpu))
 426       != SIM_RC_OK)
 427     {
 428       free_state (sd);
 429       return 0;
 430     }
 431
 432   cpu = STATE_CPU (sd, 0);
 433
 434   cpu_initialize (sd, cpu);
 435
 436   if (sim_pre_argv_init (sd, argv[0]) != SIM_RC_OK)
 437     {
 438       free_state (sd);
 439       return 0;
 440     }
 441
 442   /* The parser will print an error message for us, so we silently return.  */
 443   if (sim_parse_args (sd, argv) != SIM_RC_OK)
 444     {
 445       /* Uninstall the modules to avoid memory leaks,
 446          file descriptor leaks, etc.  */
 447       free_state (sd);
 448       return 0;
 449     }
 450
 451   /* Check for/establish the a reference program image.  */
 452   if (sim_analyze_program (sd, STATE_PROG_FILE (sd), abfd) != SIM_RC_OK)
 453     {
 454       free_state (sd);
 455       return 0;
 456     }
 457
 458   /* Establish any remaining configuration options.  */
 459   if (sim_config (sd) != SIM_RC_OK)
 460     {
 461       free_state (sd);
 462       return 0;
 463     }
 464
 465   if (sim_post_argv_init (sd) != SIM_RC_OK)
 466     {
 467       /* Uninstall the modules to avoid memory leaks,
 468          file descriptor leaks, etc.  */
 469       free_state (sd);
 470       return 0;
 471     }
 472   if (sim_prepare_for_program (sd, abfd) != SIM_RC_OK)
 473     {
 474       free_state (sd);
 475       return 0;
 476     }
 477
 478   /* CPU specific initialization.  */
 479   for (i = 0; i < MAX_NR_PROCESSORS; ++i)
 480     {
 481       SIM_CPU *cpu = STATE_CPU (sd, i);
 482
 483       CPU_REG_FETCH (cpu) = m68hc11_reg_fetch;
 484       CPU_REG_STORE (cpu) = m68hc11_reg_store;
 485       CPU_PC_FETCH (cpu) = m68hc11_pc_get;
 486       CPU_PC_STORE (cpu) = m68hc11_pc_set;
 487     }
 488
 489   return sd;
 490 }
 491
 492 /* Generic implementation of sim_engine_run that works within the
 493    sim_engine setjmp/longjmp framework. */
 494
 495 void
 496 sim_engine_run (SIM_DESC sd,
 497                 int next_cpu_nr,        /* ignore */
 498                 int nr_cpus,    /* ignore */
 499                 int siggnal)    /* ignore */
 500 {
 501   sim_cpu *cpu;
 502
 503   SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
 504   cpu = STATE_CPU (sd, 0);
 505   while (1)
 506     {
 507       cpu_single_step (cpu);
 508
 509       /* process any events */
 510       if (sim_events_tickn (sd, M68HC11_SIM_CPU (cpu)->cpu_current_cycle))
 511         {
 512           sim_events_process (sd);
 513         }
 514     }
 515 }
 516
 517 void
 518 sim_info (SIM_DESC sd, int verbose)
 519 {
 520   const char *cpu_type;
 521   const struct bfd_arch_info *arch;
 522
 523   /* Nothing to do if there is no verbose flag set.  */
 524   if (verbose == 0 && STATE_VERBOSE_P (sd) == 0)
 525     return;
 526
 527   arch = STATE_ARCHITECTURE (sd);
 528   if (arch->arch == bfd_arch_m68hc11)
 529     cpu_type = "68HC11";
 530   else
 531     cpu_type = "68HC12";
 532
 533   sim_io_eprintf (sd, "Simulator info:\n");
 534   sim_io_eprintf (sd, "  CPU Motorola %s\n", cpu_type);
 535   sim_get_info (sd, 0);
 536   sim_module_info (sd, verbose || STATE_VERBOSE_P (sd));
 537 }
 538
 539 SIM_RC
 540 sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
 541                      char * const *argv, char * const *env)
 542 {
 543   return sim_prepare_for_program (sd, abfd);
 544 }
 545
 546 static int
 547 m68hc11_reg_fetch (SIM_CPU *cpu, int rn, void *buf, int length)
 548 {
 549   unsigned char *memory = buf;
 550   uint16_t val;
 551   int size = 2;
 552
 553   switch (rn)
 554     {
 555     case A_REGNUM:
 556       val = cpu_get_a (cpu);
 557       size = 1;
 558       break;
 559
 560     case B_REGNUM:
 561       val = cpu_get_b (cpu);
 562       size = 1;
 563       break;
 564
 565     case D_REGNUM:
 566       val = cpu_get_d (cpu);
 567       break;
 568
 569     case X_REGNUM:
 570       val = cpu_get_x (cpu);
 571       break;
 572
 573     case Y_REGNUM:
 574       val = cpu_get_y (cpu);
 575       break;
 576
 577     case SP_REGNUM:
 578       val = cpu_get_sp (cpu);
 579       break;
 580
 581     case PC_REGNUM:
 582       val = cpu_get_pc (cpu);
 583       break;
 584
 585     case PSW_REGNUM:
 586       val = cpu_get_ccr (cpu);
 587       size = 1;
 588       break;
 589
 590     case PAGE_REGNUM:
 591       val = cpu_get_page (cpu);
 592       size = 1;
 593       break;
 594
 595     default:
 596       val = 0;
 597       break;
 598     }
 599   if (size == 1)
 600     {
 601       memory[0] = val;
 602     }
 603   else
 604     {
 605       memory[0] = val >> 8;
 606       memory[1] = val & 0x0FF;
 607     }
 608   return size;
 609 }
 610
 611 static int
 612 m68hc11_reg_store (SIM_CPU *cpu, int rn, const void *buf, int length)
 613 {
 614   const unsigned char *memory = buf;
 615   uint16_t val;
 616
 617   val = *memory++;
 618   if (length == 2)
 619     val = (val << 8) | *memory;
 620
 621   switch (rn)
 622     {
 623     case D_REGNUM:
 624       cpu_set_d (cpu, val);
 625       break;
 626
 627     case A_REGNUM:
 628       cpu_set_a (cpu, val);
 629       return 1;
 630
 631     case B_REGNUM:
 632       cpu_set_b (cpu, val);
 633       return 1;
 634
 635     case X_REGNUM:
 636       cpu_set_x (cpu, val);
 637       break;
 638
 639     case Y_REGNUM:
 640       cpu_set_y (cpu, val);
 641       break;
 642
 643     case SP_REGNUM:
 644       cpu_set_sp (cpu, val);
 645       break;
 646
 647     case PC_REGNUM:
 648       cpu_set_pc (cpu, val);
 649       break;
 650
 651     case PSW_REGNUM:
 652       cpu_set_ccr (cpu, val);
 653       return 1;
 654
 655     case PAGE_REGNUM:
 656       cpu_set_page (cpu, val);
 657       return 1;
 658
 659     default:
 660       break;
 661     }
 662
 663   return 2;
 664 }