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root/cebix/BasiliskII/src/BeOS/main_beos.cpp
Revision: 1.4
Committed: 2000-07-14T21:29:13Z (24 years, 4 months ago) by cebix
Branch: MAIN
Changes since 1.3: +2 -0 lines
Log Message:
- AmigaOS bug fixes by J.Lachmann (floppy, 2060scsi.device, "Add Volume" in
  prefs editor)
- imported some changes from the Windows source (1Hz interrupt, FPU fixes)

File Contents

# User Rev Content
1 cebix 1.1 /*
2     * main_beos.cpp - Startup code for BeOS
3     *
4 cebix 1.3 * Basilisk II (C) 1997-2000 Christian Bauer
5 cebix 1.1 *
6     * This program is free software; you can redistribute it and/or modify
7     * it under the terms of the GNU General Public License as published by
8     * the Free Software Foundation; either version 2 of the License, or
9     * (at your option) any later version.
10     *
11     * This program is distributed in the hope that it will be useful,
12     * but WITHOUT ANY WARRANTY; without even the implied warranty of
13     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14     * GNU General Public License for more details.
15     *
16     * You should have received a copy of the GNU General Public License
17     * along with this program; if not, write to the Free Software
18     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19     */
20    
21     #include <AppKit.h>
22     #include <InterfaceKit.h>
23     #include <KernelKit.h>
24     #include <StorageKit.h>
25    
26     #include <unistd.h>
27     #include <fcntl.h>
28     #include <signal.h>
29     #include <stdio.h>
30     #include <stdlib.h>
31     #include <time.h>
32    
33     #include "sysdeps.h"
34     #include "cpu_emulation.h"
35     #include "xpram.h"
36     #include "timer.h"
37     #include "video.h"
38     #include "rom_patches.h"
39     #include "prefs.h"
40     #include "prefs_editor.h"
41     #include "sys.h"
42     #include "user_strings.h"
43     #include "version.h"
44     #include "main.h"
45    
46     #include "sheep_driver.h"
47    
48     #define DEBUG 0
49     #include "debug.h"
50    
51    
52     // Constants
53     const char APP_SIGNATURE[] = "application/x-vnd.cebix-BasiliskII";
54     const char ROM_FILE_NAME[] = "ROM";
55     const char RAM_AREA_NAME[] = "Macintosh RAM";
56     const char ROM_AREA_NAME[] = "Macintosh ROM";
57     const uint32 MSG_START = 'strt'; // Emulator start message
58     const uint32 ROM_AREA_SIZE = 0x500000; // Enough to hold PowerMac ROM (for powerrom_cpu)
59    
60     // Prototypes
61     #if __POWERPC__
62     static void sigsegv_handler(vregs *r);
63     #endif
64    
65    
66     // Application object
67     class BasiliskII : public BApplication {
68     public:
69     BasiliskII() : BApplication(APP_SIGNATURE)
70     {
71     // Find application directory and cwd to it
72     app_info the_info;
73     GetAppInfo(&the_info);
74     BEntry the_file(&the_info.ref);
75     BEntry the_dir;
76     the_file.GetParent(&the_dir);
77     BPath the_path;
78     the_dir.GetPath(&the_path);
79     chdir(the_path.Path());
80    
81     // Initialize other variables
82     rom_area = ram_area = -1;
83     xpram_thread = tick_thread = -1;
84     xpram_thread_active = true;
85     tick_thread_active = true;
86     AllowQuitting = true;
87     }
88     virtual void ReadyToRun(void);
89     virtual void MessageReceived(BMessage *msg);
90     void StartEmulator(void);
91     virtual bool QuitRequested(void);
92     virtual void Quit(void);
93    
94     thread_id xpram_thread; // XPRAM watchdog
95     thread_id tick_thread; // 60Hz thread
96    
97     volatile bool xpram_thread_active; // Flag for quitting the XPRAM thread
98     volatile bool tick_thread_active; // Flag for quitting the 60Hz thread
99    
100     bool AllowQuitting; // Flag: Alt-Q quitting allowed
101    
102     private:
103     static status_t emul_func(void *arg);
104     static status_t tick_func(void *arg);
105     static status_t xpram_func(void *arg);
106     static void sigsegv_invoc(int sig, void *arg, vregs *r);
107    
108     void init_rom(void);
109     void load_rom(void);
110    
111     area_id rom_area; // ROM area ID
112     area_id ram_area; // RAM area ID
113    
114     struct sigaction sigsegv_action; // Data access exception signal (of emulator thread)
115    
116     // Exceptions
117     class area_error {};
118     class file_open_error {};
119     class file_read_error {};
120     class rom_size_error {};
121     };
122    
123     static BasiliskII *the_app;
124    
125    
126     // CPU and FPU type, addressing mode
127     int CPUType;
128     bool CPUIs68060;
129     int FPUType;
130     bool TwentyFourBitAddressing;
131    
132    
133     // Global variables for PowerROM CPU
134     thread_id emul_thread = -1; // Emulator thread
135    
136     #if __POWERPC__
137     int sheep_fd = -1; // fd of sheep driver
138     #endif
139    
140    
141     /*
142     * Create application object and start it
143     */
144    
145     int main(int argc, char **argv)
146     {
147     the_app = new BasiliskII();
148     the_app->Run();
149     delete the_app;
150     return 0;
151     }
152    
153    
154     /*
155     * Run application
156     */
157    
158     void BasiliskII::ReadyToRun(void)
159     {
160     // Initialize variables
161     RAMBaseHost = NULL;
162     ROMBaseHost = NULL;
163     srand(real_time_clock());
164     tzset();
165    
166     // Print some info
167     printf(GetString(STR_ABOUT_TEXT1), VERSION_MAJOR, VERSION_MINOR);
168     printf(" %s\n", GetString(STR_ABOUT_TEXT2));
169    
170     // Delete old areas
171     area_id old_ram_area = find_area(RAM_AREA_NAME);
172     if (old_ram_area > 0)
173     delete_area(old_ram_area);
174     area_id old_rom_area = find_area(ROM_AREA_NAME);
175     if (old_rom_area > 0)
176     delete_area(old_rom_area);
177    
178     // Read preferences
179     PrefsInit();
180    
181     // Init system routines
182     SysInit();
183    
184     // Show preferences editor (or start emulator directly)
185     if (!PrefsFindBool("nogui"))
186     PrefsEditor();
187     else
188     PostMessage(MSG_START);
189     }
190    
191    
192     /*
193     * Message received
194     */
195    
196     void BasiliskII::MessageReceived(BMessage *msg)
197     {
198     switch (msg->what) {
199     case MSG_START:
200     StartEmulator();
201     break;
202     default:
203     BApplication::MessageReceived(msg);
204     }
205     }
206    
207    
208     /*
209     * Start emulator
210     */
211    
212     void BasiliskII::StartEmulator(void)
213     {
214     char str[256];
215    
216     #if REAL_ADDRESSING
217     // Open memory mess driver and remap low memory
218     sheep_fd = open("/dev/sheep", 0);
219     if (sheep_fd < 0) {
220     sprintf(str, GetString(STR_NO_SHEEP_DRIVER_ERR), strerror(sheep_fd), sheep_fd);
221     ErrorAlert(str);
222     PostMessage(B_QUIT_REQUESTED);
223     return;
224     }
225     status_t res = ioctl(sheep_fd, SHEEP_UP);
226     if (res < 0) {
227     sprintf(str, GetString(STR_SHEEP_UP_ERR), strerror(res), res);
228     ErrorAlert(str);
229     PostMessage(B_QUIT_REQUESTED);
230     return;
231     }
232     #endif
233    
234     // Create area for Mac RAM
235     RAMSize = PrefsFindInt32("ramsize") & 0xfff00000; // Round down to 1MB boundary
236     if (RAMSize < 1024*1024) {
237     WarningAlert(GetString(STR_SMALL_RAM_WARN));
238     RAMSize = 1024*1024;
239     }
240    
241     RAMBaseHost = (uint8 *)0x10000000;
242     ram_area = create_area(RAM_AREA_NAME, (void **)&RAMBaseHost, B_BASE_ADDRESS, RAMSize, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
243     if (ram_area < 0) {
244     ErrorAlert(GetString(STR_NO_RAM_AREA_ERR));
245     PostMessage(B_QUIT_REQUESTED);
246     return;
247     }
248     D(bug("RAM area %ld at %p\n", ram_area, RAMBaseHost));
249    
250     // Create area and load Mac ROM
251     try {
252     init_rom();
253     } catch (area_error) {
254     ErrorAlert(GetString(STR_NO_ROM_AREA_ERR));
255     PostMessage(B_QUIT_REQUESTED);
256     return;
257     } catch (file_open_error) {
258     ErrorAlert(GetString(STR_NO_ROM_FILE_ERR));
259     PostMessage(B_QUIT_REQUESTED);
260     return;
261     } catch (file_read_error) {
262     ErrorAlert(GetString(STR_ROM_FILE_READ_ERR));
263     PostMessage(B_QUIT_REQUESTED);
264     return;
265     } catch (rom_size_error) {
266     ErrorAlert(GetString(STR_ROM_SIZE_ERR));
267     PostMessage(B_QUIT_REQUESTED);
268     return;
269     }
270    
271 cebix 1.2 // Initialize everything
272     if (!InitAll()) {
273 cebix 1.1 PostMessage(B_QUIT_REQUESTED);
274     return;
275     }
276    
277 cebix 1.2 // Write protect ROM
278     set_area_protection(rom_area, B_READ_AREA);
279 cebix 1.1
280 cebix 1.2 // Disallow quitting with Alt-Q from now on
281     AllowQuitting = false;
282 cebix 1.1
283     // Start XPRAM watchdog thread
284     xpram_thread = spawn_thread(xpram_func, "XPRAM Watchdog", B_LOW_PRIORITY, this);
285     resume_thread(xpram_thread);
286    
287     // Start 60Hz interrupt
288     tick_thread = spawn_thread(tick_func, "60Hz", B_REAL_TIME_PRIORITY, this);
289     resume_thread(tick_thread);
290    
291     // Start emulator thread
292     emul_thread = spawn_thread(emul_func, "MacOS", B_NORMAL_PRIORITY, this);
293     resume_thread(emul_thread);
294     }
295    
296    
297     /*
298     * Quit emulator
299     */
300    
301     void QuitEmulator(void)
302     {
303     the_app->AllowQuitting = true;
304     be_app->PostMessage(B_QUIT_REQUESTED);
305     exit_thread(0);
306     }
307    
308     bool BasiliskII::QuitRequested(void)
309     {
310     if (AllowQuitting)
311     return BApplication::QuitRequested();
312     else
313     return false;
314     }
315    
316     void BasiliskII::Quit(void)
317     {
318     status_t l;
319    
320     // Stop 60Hz interrupt
321     if (tick_thread > 0) {
322     tick_thread_active = false;
323     wait_for_thread(tick_thread, &l);
324     }
325    
326     // Wait for emulator thread to finish
327     if (emul_thread > 0)
328     wait_for_thread(emul_thread, &l);
329    
330     // Exit 680x0 emulation
331     Exit680x0();
332    
333     // Stop XPRAM watchdog thread
334     if (xpram_thread > 0) {
335     xpram_thread_active = false;
336     suspend_thread(xpram_thread); // Wake thread up from snooze()
337     snooze(1000);
338     resume_thread(xpram_thread);
339     wait_for_thread(xpram_thread, &l);
340     }
341    
342 cebix 1.2 // Deinitialize everything
343     ExitAll();
344 cebix 1.1
345     // Delete ROM area
346     if (rom_area >= 0)
347     delete_area(rom_area);
348    
349     // Delete RAM area
350     if (ram_area >= 0)
351     delete_area(ram_area);
352    
353     #if REAL_ADDRESSING
354     // Unmap low memory and close memory mess driver
355     if (sheep_fd >= 0) {
356     ioctl(sheep_fd, SHEEP_DOWN);
357     close(sheep_fd);
358     }
359     #endif
360    
361     // Exit system routines
362     SysExit();
363    
364     // Exit preferences
365     PrefsExit();
366    
367     BApplication::Quit();
368     }
369    
370    
371     /*
372     * Create area for ROM (sets rom_area) and load ROM file
373     *
374     * area_error : Cannot create area
375     * file_open_error: Cannot open ROM file
376     * file_read_error: Cannot read ROM file
377     */
378    
379     void BasiliskII::init_rom(void)
380     {
381     // Create area for ROM
382     ROMBaseHost = (uint8 *)0x40800000;
383     rom_area = create_area(ROM_AREA_NAME, (void **)&ROMBaseHost, B_BASE_ADDRESS, ROM_AREA_SIZE, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
384     if (rom_area < 0)
385     throw area_error();
386     D(bug("ROM area %ld at %p\n", rom_area, ROMBaseHost));
387    
388     // Load ROM
389     load_rom();
390     }
391    
392    
393     /*
394     * Load ROM file
395     *
396     * file_open_error: Cannot open ROM file
397     * file_read_error: Cannot read ROM file
398     */
399    
400     void BasiliskII::load_rom(void)
401     {
402     // Get rom file path from preferences
403     const char *rom_path = PrefsFindString("rom");
404    
405     // Try to open ROM file
406     BFile file(rom_path ? rom_path : ROM_FILE_NAME, B_READ_ONLY);
407     if (file.InitCheck() != B_NO_ERROR)
408     throw file_open_error();
409    
410     printf(GetString(STR_READING_ROM_FILE));
411    
412     // Is the ROM size correct?
413     off_t rom_size = 0;
414     file.GetSize(&rom_size);
415     if (rom_size != 64*1024 && rom_size != 128*1024 && rom_size != 256*1024 && rom_size != 512*1024 && rom_size != 1024*1024)
416     throw rom_size_error();
417    
418     uint8 *rom = new uint8[rom_size]; // Reading directly into the area doesn't work
419     ssize_t actual = file.Read((void *)rom, rom_size);
420     if (actual == rom_size)
421     memcpy(ROMBaseHost, rom, rom_size);
422     delete[] rom;
423     if (actual != rom_size)
424     throw file_read_error();
425     ROMSize = rom_size;
426     }
427    
428    
429     /*
430     * Emulator thread function
431     */
432    
433     status_t BasiliskII::emul_func(void *arg)
434     {
435     BasiliskII *obj = (BasiliskII *)arg;
436    
437     #if __POWERPC__
438     // Install data access signal handler
439     sigemptyset(&obj->sigsegv_action.sa_mask);
440     obj->sigsegv_action.sa_handler = (__signal_func_ptr)(obj->sigsegv_invoc);
441     obj->sigsegv_action.sa_flags = 0;
442     obj->sigsegv_action.sa_userdata = arg;
443     sigaction(SIGSEGV, &obj->sigsegv_action, NULL);
444     #endif
445    
446     // Exceptions will send signals
447     disable_debugger(true);
448    
449     // Start 68k and jump to ROM boot routine
450     Start680x0();
451    
452     // Quit program
453     obj->AllowQuitting = true;
454     be_app->PostMessage(B_QUIT_REQUESTED);
455     return 0;
456     }
457    
458    
459     /*
460     * Code was patched, flush caches if neccessary (i.e. when using a real 680x0
461     * or a dynamically recompiling emulator)
462     */
463    
464     void FlushCodeCache(void *start, uint32 size)
465     {
466     }
467    
468    
469     /*
470     * Interrupt flags (must be handled atomically!)
471     */
472    
473     uint32 InterruptFlags = 0;
474    
475     void SetInterruptFlag(uint32 flag)
476     {
477     atomic_or((int32 *)&InterruptFlags, flag);
478     }
479    
480     void ClearInterruptFlag(uint32 flag)
481     {
482     atomic_and((int32 *)&InterruptFlags, ~flag);
483     }
484    
485    
486     /*
487     * 60Hz thread (really 60.15Hz)
488     */
489    
490     status_t BasiliskII::tick_func(void *arg)
491     {
492     BasiliskII *obj = (BasiliskII *)arg;
493     int tick_counter = 0;
494     bigtime_t current = system_time();
495    
496     while (obj->tick_thread_active) {
497    
498     // Wait
499     current += 16625;
500     snooze_until(current, B_SYSTEM_TIMEBASE);
501    
502     // Pseudo Mac 1Hz interrupt, update local time
503     if (++tick_counter > 60) {
504     tick_counter = 0;
505     WriteMacInt32(0x20c, TimerDateTime());
506 cebix 1.4 SetInterruptFlag(INTFLAG_1HZ);
507     TriggerInterrupt();
508 cebix 1.1 }
509    
510     // Trigger 60Hz interrupt
511     SetInterruptFlag(INTFLAG_60HZ);
512     TriggerInterrupt();
513     }
514     return 0;
515     }
516    
517    
518     /*
519     * XPRAM watchdog thread (saves XPRAM every minute)
520     */
521    
522     status_t BasiliskII::xpram_func(void *arg)
523     {
524     uint8 last_xpram[256];
525     memcpy(last_xpram, XPRAM, 256);
526    
527     while (((BasiliskII *)arg)->xpram_thread_active) {
528     snooze(60*1000000);
529     if (memcmp(last_xpram, XPRAM, 256)) {
530     memcpy(last_xpram, XPRAM, 256);
531     SaveXPRAM();
532     }
533     }
534     return 0;
535     }
536    
537    
538     /*
539     * Display error alert
540     */
541    
542     void ErrorAlert(const char *text)
543     {
544     if (PrefsFindBool("nogui")) {
545     printf(GetString(STR_SHELL_ERROR_PREFIX), text);
546     return;
547     }
548     VideoQuitFullScreen();
549     char str[256];
550     sprintf(str, GetString(STR_GUI_ERROR_PREFIX), text);
551     BAlert *alert = new BAlert(GetString(STR_ERROR_ALERT_TITLE), str, GetString(STR_QUIT_BUTTON), NULL, NULL, B_WIDTH_AS_USUAL, B_STOP_ALERT);
552     alert->Go();
553     }
554    
555    
556     /*
557     * Display warning alert
558     */
559    
560     void WarningAlert(const char *text)
561     {
562     if (PrefsFindBool("nogui")) {
563     printf(GetString(STR_SHELL_WARNING_PREFIX), text);
564     return;
565     }
566     char str[256];
567     sprintf(str, GetString(STR_GUI_WARNING_PREFIX), text);
568     BAlert *alert = new BAlert(GetString(STR_WARNING_ALERT_TITLE), str, GetString(STR_OK_BUTTON), NULL, NULL, B_WIDTH_AS_USUAL, B_INFO_ALERT);
569     alert->Go();
570     }
571    
572    
573     /*
574     * Display choice alert
575     */
576    
577     bool ChoiceAlert(const char *text, const char *pos, const char *neg)
578     {
579     char str[256];
580     sprintf(str, GetString(STR_GUI_WARNING_PREFIX), text);
581     BAlert *alert = new BAlert(GetString(STR_WARNING_ALERT_TITLE), str, pos, neg, NULL, B_WIDTH_AS_USUAL, B_INFO_ALERT);
582     return alert->Go() == 0;
583     }
584    
585    
586     /*
587     * SEGV handler
588     */
589    
590     #if __POWERPC__
591     static uint32 segv_r[32];
592    
593     asm void BasiliskII::sigsegv_invoc(register int sig, register void *arg, register vregs *r)
594     {
595     mflr r0
596     stw r0,8(r1)
597     stwu r1,-56(r1)
598    
599     lwz r3,segv_r(r2)
600     stmw r13,13*4(r3)
601    
602     mr r3,r5
603     bl sigsegv_handler
604    
605     lwz r3,segv_r(r2)
606     lmw r13,13*4(r3)
607    
608     lwz r0,56+8(r1)
609     mtlr r0
610     addi r1,r1,56
611     blr
612     }
613    
614     static void sigsegv_handler(vregs *r)
615     {
616     // Fetch volatile registers
617     segv_r[0] = r->r0;
618     segv_r[1] = r->r1;
619     segv_r[2] = r->r2;
620     segv_r[3] = r->r3;
621     segv_r[4] = r->r4;
622     segv_r[5] = r->r5;
623     segv_r[6] = r->r6;
624     segv_r[7] = r->r7;
625     segv_r[8] = r->r8;
626     segv_r[9] = r->r9;
627     segv_r[10] = r->r10;
628     segv_r[11] = r->r11;
629     segv_r[12] = r->r12;
630    
631     // Get opcode and divide into fields
632     uint32 opcode = *(uint32 *)r->pc;
633     uint32 primop = opcode >> 26;
634     uint32 exop = (opcode >> 1) & 0x3ff;
635     uint32 ra = (opcode >> 16) & 0x1f;
636     uint32 rb = (opcode >> 11) & 0x1f;
637     uint32 rd = (opcode >> 21) & 0x1f;
638     uint32 imm = opcode & 0xffff;
639    
640     // Analyze opcode
641     enum {
642     TYPE_UNKNOWN,
643     TYPE_LOAD,
644     TYPE_STORE
645     } transfer_type = TYPE_UNKNOWN;
646     enum {
647     SIZE_UNKNOWN,
648     SIZE_BYTE,
649     SIZE_HALFWORD,
650     SIZE_WORD
651     } transfer_size = SIZE_UNKNOWN;
652     enum {
653     MODE_UNKNOWN,
654     MODE_NORM,
655     MODE_U,
656     MODE_X,
657     MODE_UX
658     } addr_mode = MODE_UNKNOWN;
659     switch (primop) {
660     case 31:
661     switch (exop) {
662     case 23: // lwzx
663     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
664     case 55: // lwzux
665     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
666     case 87: // lbzx
667     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
668     case 119: // lbzux
669     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
670     case 151: // stwx
671     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
672     case 183: // stwux
673     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
674     case 215: // stbx
675     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
676     case 247: // stbux
677     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
678     case 279: // lhzx
679     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
680     case 311: // lhzux
681     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
682     case 343: // lhax
683     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
684     case 375: // lhaux
685     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
686     case 407: // sthx
687     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
688     case 439: // sthux
689     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
690     }
691     break;
692    
693     case 32: // lwz
694     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
695     case 33: // lwzu
696     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
697     case 34: // lbz
698     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
699     case 35: // lbzu
700     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
701     case 36: // stw
702     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
703     case 37: // stwu
704     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
705     case 38: // stb
706     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
707     case 39: // stbu
708     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
709     case 40: // lhz
710     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
711     case 41: // lhzu
712     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
713     case 42: // lha
714     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
715     case 43: // lhau
716     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
717     case 44: // sth
718     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
719     case 45: // sthu
720     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
721     }
722    
723     // Calculate effective address
724     uint32 addr = 0;
725     switch (addr_mode) {
726     case MODE_X:
727     case MODE_UX:
728     if (ra == 0)
729     addr = segv_r[rb];
730     else
731     addr = segv_r[ra] + segv_r[rb];
732     break;
733     case MODE_NORM:
734     case MODE_U:
735     if (ra == 0)
736     addr = (int32)(int16)imm;
737     else
738     addr = segv_r[ra] + (int32)(int16)imm;
739     break;
740     }
741    
742     // Ignore ROM writes
743     if (transfer_type == TYPE_STORE && addr >= (uint32)ROMBaseHost && addr < (uint32)ROMBaseHost + ROMSize) {
744     // D(bug("WARNING: %s write access to ROM at %p, 68k pc %p\n", transfer_size == SIZE_BYTE ? "Byte" : transfer_size == SIZE_HALFWORD ? "Halfword" : "Word", addr, r->pc));
745     if (addr_mode == MODE_U || addr_mode == MODE_UX)
746     segv_r[ra] = addr;
747     r->pc += 4;
748     goto rti;
749     }
750    
751     // For all other errors, jump into debugger
752     char str[256];
753     sprintf(str, "SIGSEGV\n"
754     " pc %08lx lr %08lx ctr %08lx msr %08lx\n"
755     " xer %08lx cr %08lx fpscr %08lx\n"
756     " r0 %08lx r1 %08lx r2 %08lx r3 %08lx\n"
757     " r4 %08lx r5 %08lx r6 %08lx r7 %08lx\n"
758     " r8 %08lx r9 %08lx r10 %08lx r11 %08lx\n"
759     " r12 %08lx r13 %08lx r14 %08lx r15 %08lx\n"
760     " r16 %08lx r17 %08lx r18 %08lx r19 %08lx\n"
761     " r20 %08lx r21 %08lx r22 %08lx r23 %08lx\n"
762     " r24 %08lx r25 %08lx r26 %08lx r27 %08lx\n"
763     " r28 %08lx r29 %08lx r30 %08lx r31 %08lx\n",
764     r->pc, r->lr, r->ctr, r->msr,
765     r->xer, r->cr, r->fpscr,
766     r->r0, r->r1, r->r2, r->r3,
767     r->r4, r->r5, r->r6, r->r7,
768     r->r8, r->r9, r->r10, r->r11,
769     r->r12, segv_r[13], segv_r[14], segv_r[15],
770     segv_r[16], segv_r[17], segv_r[18], segv_r[19],
771     segv_r[20], segv_r[21], segv_r[22], segv_r[23],
772     segv_r[24], segv_r[25], segv_r[26], segv_r[27],
773     segv_r[28], segv_r[29], segv_r[30], segv_r[31]);
774     disable_debugger(false);
775     debugger(str);
776     QuitEmulator();
777     return;
778    
779     rti:
780     // Restore volatile registers
781     r->r0 = segv_r[0];
782     r->r1 = segv_r[1];
783     r->r2 = segv_r[2];
784     r->r3 = segv_r[3];
785     r->r4 = segv_r[4];
786     r->r5 = segv_r[5];
787     r->r6 = segv_r[6];
788     r->r7 = segv_r[7];
789     r->r8 = segv_r[8];
790     r->r9 = segv_r[9];
791     r->r10 = segv_r[10];
792     r->r11 = segv_r[11];
793     r->r12 = segv_r[12];
794     }
795     #endif