1 // license:BSD-3-Clause
2 // copyright-holders:Nathan Woods
3 /*** m6809: Portable 6809 emulator ******************************************
4
5 Copyright John Butler
6
7 References:
8
9 6809 Simulator V09, By L.C. Benschop, Eindhoven The Netherlands.
10
11 m6809: Portable 6809 emulator, DS (6809 code in MAME, derived from
12 the 6809 Simulator V09)
13
14 6809 Microcomputer Programming & Interfacing with Experiments"
15 by Andrew C. Staugaard, Jr.; Howard W. Sams & Co., Inc.
16
17 System dependencies: uint16_t must be 16 bit unsigned int
18 uint8_t must be 8 bit unsigned int
19 uint32_t must be more than 16 bits
20 arrays up to 65536 bytes must be supported
21 machine must be twos complement
22
23 History:
24
25 July 2016 ErikGav:
26 Unify with 6309 pairs and quads (A+B=D, E+F=W, D+W=Q)
27
28 March 2013 NPW:
29 Rewrite of 6809/6309/Konami CPU; attempted to make cycle exact.
30
31 991026 HJB:
32 Fixed missing calls to cpu_changepc() for the TFR and EXG ocpodes.
33 Replaced m6809_slapstic checks by a macro (CHANGE_PC). ESB still
34 needs the tweaks.
35
36 991024 HJB:
37 Tried to improve speed: Using bit7 of cycles1/2 as flag for multi
38 byte opcodes is gone, those opcodes now call fetch_effective_address().
39 Got rid of the slow/fast flags for stack (S and U) memory accesses.
40 Minor changes to use 32 bit values as arguments to memory functions
41 and added defines for that purpose (e.g. X = 16bit XD = 32bit).
42
43 990312 HJB:
44 Added bugfixes according to Aaron's findings.
45 Reset only sets CC_II and CC_IF, DP to zero and PC from reset vector.
46 990311 HJB:
47 Added _info functions. Now uses static m6808_Regs struct instead
48 of single statics. Changed the 16 bit registers to use the generic
49 PAIR union. Registers defined using macros. Split the core into
50 four execution loops for M6802, M6803, M6808 and HD63701.
51 TST, TSTA and TSTB opcodes reset carry flag.
52 Modified the read/write stack handlers to push LSB first then MSB
53 and pull MSB first then LSB.
54
55 990228 HJB:
56 Changed the interrupt handling again. Now interrupts are taken
57 either right at the moment the lines are asserted or whenever
58 an interrupt is enabled and the corresponding line is still
59 asserted. That way the pending_interrupts checks are not
60 needed anymore. However, the CWAI and SYNC flags still need
61 some flags, so I changed the name to 'int_state'.
62 This core also has the code for the old interrupt system removed.
63
64 990225 HJB:
65 Cleaned up the code here and there, added some comments.
66 Slightly changed the SAR opcodes (similiar to other CPU cores).
67 Added symbolic names for the flag bits.
68 Changed the way CWAI/Interrupt() handle CPU state saving.
69 A new flag M6809_STATE in pending_interrupts is used to determine
70 if a state save is needed on interrupt entry or already done by CWAI.
71 Added M6809_IRQ_LINE and M6809_FIRQ_LINE defines to m6809.h
72 Moved the internal interrupt_pending flags from m6809.h to m6809.c
73 Changed CWAI cycles2[0x3c] to be 2 (plus all or at least 19 if
74 CWAI actually pushes the entire state).
75 Implemented undocumented TFR/EXG for undefined source and mixed 8/16
76 bit transfers (they should transfer/exchange the constant $ff).
77 Removed unused jmp/jsr _slap functions from 6809ops.c,
78 m6809_slapstick check moved into the opcode functions.
79
80 ******************************************************************************
81
82 M6809 cycle timings are relative to a four-phase clock cycle defined by
83 the Q and E signals on pins 35 and 34. The Q clock must lead the E clock
84 by approximately half a cycle. On the MC6809E, Q and E are inputs, and
85 one 74LS74 wired as a two-stage Johnson counter is almost sufficient to
86 generate both (though E requires voltage levels above TTL). On the
87 MC6809, however, Q and E are output from an internal clock generator
88 which can be driven by a crystal oscillator connected to pins 38 and 39.
89 (The MC6809E reuses the same numbered pins for the unrelated TSC and LIC
90 functions.) The frequencies of Q and E on the MC6809 are that of the XTAL
91 divided by 4. MAME's emulation formerly assigned this internal clock
92 divider to the MC6809E and not to the MC6809; the confusion resulting
93 from this error is in the process of being straightened out.
94
95 Maximum clock ratings:
96
97 Q & E EXTAL
98 MC6809(E) 1.0 MHz 4.0 MHz
99 MC68A09(E) 1.5 MHz 6.0 MHz
100 MC68B09(E) 2.0 MHz 8.0 MHz
101 HD63B09(E) 2.0 MHz 8.0 MHz
102 HD63C09(E) 3.0 MHz 12.0 MHz
103
104 *****************************************************************************/
105
106 #include "emu.h"
107 #include "debugger.h"
108 #include "m6809.h"
109 #include "m6809inl.h"
110 #include "6x09dasm.h"
111
112
113 //**************************************************************************
114 // PARAMETERS
115 //**************************************************************************
116
117 #define LOG_INTERRUPTS 0
118
119 // turn off 'unreferenced label' errors
120 #if defined(__GNUC__)
121 #pragma GCC diagnostic ignored "-Wunused-label"
122 #endif
123 #ifdef _MSC_VER
124 #pragma warning( disable : 4102 )
125 #endif
126
127 //**************************************************************************
128 // DEVICE INTERFACE
129 //**************************************************************************
130
131 DEFINE_DEVICE_TYPE(MC6809, mc6809_device, "mc6809", "Motorola MC6809")
132 DEFINE_DEVICE_TYPE(MC6809E, mc6809e_device, "mc6809e", "Motorola MC6809E")
133 DEFINE_DEVICE_TYPE(M6809, m6809_device, "m6809", "MC6809 (legacy)")
134
135
136 //-------------------------------------------------
137 // m6809_base_device - constructor
138 //-------------------------------------------------
139
m6809_base_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock,const device_type type,int divider)140 m6809_base_device::m6809_base_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock, const device_type type, int divider)
141 : cpu_device(mconfig, type, tag, owner, clock),
142 m_lic_func(*this),
143 m_program_config("program", ENDIANNESS_BIG, 8, 16),
144 m_sprogram_config("decrypted_opcodes", ENDIANNESS_BIG, 8, 16),
145 m_clock_divider(divider)
146 {
147 m_mintf = nullptr;
148 }
149
150 //-------------------------------------------------
151 // device_start - device-specific startup
152 //-------------------------------------------------
153
device_start()154 void m6809_base_device::device_start()
155 {
156 if (!m_mintf)
157 m_mintf = std::make_unique<mi_default>();
158
159 space(AS_PROGRAM).cache(m_mintf->cprogram);
160 space(AS_PROGRAM).specific(m_mintf->program);
161 space(has_space(AS_OPCODES) ? AS_OPCODES : AS_PROGRAM).cache(m_mintf->csprogram);
162
163 m_lic_func.resolve_safe();
164
165 // register our state for the debugger
166 state_add(STATE_GENPCBASE, "CURPC", m_ppc.w).callimport().noshow();
167 state_add(STATE_GENFLAGS, "CURFLAGS", m_cc).formatstr("%8s").noshow();
168 state_add(M6809_PC, "PC", m_pc.w).callimport().mask(0xffff);
169 state_add(M6809_S, "S", m_s.w).mask(0xffff);
170 state_add(M6809_CC, "CC", m_cc).mask(0xff);
171 state_add(M6809_DP, "DP", m_dp).mask(0xff);
172
173 if (is_6809())
174 {
175 state_add(M6809_A, "A", m_q.r.a).mask(0xff);
176 state_add(M6809_B, "B", m_q.r.b).mask(0xff);
177 state_add(M6809_D, "D", m_q.r.d).mask(0xffff);
178 state_add(M6809_X, "X", m_x.w).mask(0xffff);
179 state_add(M6809_Y, "Y", m_y.w).mask(0xffff);
180 state_add(M6809_U, "U", m_u.w).mask(0xffff);
181 }
182
183 // initialize variables
184 m_cc = 0;
185 m_pc.w = 0;
186 m_s.w = 0;
187 m_u.w = 0;
188 m_q.q = 0;
189 m_x.w = 0;
190 m_y.w = 0;
191 m_dp = 0;
192 m_reg = 0;
193 m_reg8 = nullptr;
194 m_reg16 = nullptr;
195
196 // setup regtable
197 save_item(NAME(m_pc.w));
198 save_item(NAME(m_ppc.w));
199 save_item(NAME(m_q.q));
200 save_item(NAME(m_dp));
201 save_item(NAME(m_u.w));
202 save_item(NAME(m_s.w));
203 save_item(NAME(m_x.w));
204 save_item(NAME(m_y.w));
205 save_item(NAME(m_cc));
206 save_item(NAME(m_temp.w));
207 save_item(NAME(m_opcode));
208 save_item(NAME(m_nmi_asserted));
209 save_item(NAME(m_nmi_line));
210 save_item(NAME(m_firq_line));
211 save_item(NAME(m_irq_line));
212 save_item(NAME(m_lds_encountered));
213 save_item(NAME(m_state));
214 save_item(NAME(m_ea.w));
215 save_item(NAME(m_addressing_mode));
216 save_item(NAME(m_reg));
217 save_item(NAME(m_cond));
218
219 // set our instruction counter
220 set_icountptr(m_icount);
221 m_icount = 0;
222 }
223
224
225
226 //-------------------------------------------------
227 // device_reset - device-specific reset
228 //-------------------------------------------------
229
device_reset()230 void m6809_base_device::device_reset()
231 {
232 m_nmi_line = false;
233 m_nmi_asserted = false;
234 m_firq_line = false;
235 m_irq_line = false;
236 m_lds_encountered = false;
237
238 m_dp = 0x00; // reset direct page register
239
240 m_cc |= CC_I; // IRQ disabled
241 m_cc |= CC_F; // FIRQ disabled
242
243 m_pc.b.h = space(AS_PROGRAM).read_byte(VECTOR_RESET_FFFE + 0);
244 m_pc.b.l = space(AS_PROGRAM).read_byte(VECTOR_RESET_FFFE + 1);
245
246 // reset sub-instruction state
247 reset_state();
248 }
249
250
251
252 //-------------------------------------------------
253 // device_pre_save - device-specific pre-save
254 //-------------------------------------------------
255
device_pre_save()256 void m6809_base_device::device_pre_save()
257 {
258 if (m_reg8 == &m_q.r.a)
259 m_reg = M6809_A;
260 else if (m_reg8 == &m_q.r.b)
261 m_reg = M6809_B;
262 else if (m_reg16 == &m_q.p.d)
263 m_reg = M6809_D;
264 else if (m_reg16 == &m_x)
265 m_reg = M6809_X;
266 else if (m_reg16 == &m_y)
267 m_reg = M6809_Y;
268 else if (m_reg16 == &m_u)
269 m_reg = M6809_U;
270 else if (m_reg16 == &m_s)
271 m_reg = M6809_S;
272 else
273 m_reg = 0;
274 }
275
276
277 //-------------------------------------------------
278 // device_post_load - device-specific post-load
279 //-------------------------------------------------
280
device_post_load()281 void m6809_base_device::device_post_load()
282 {
283 m_reg8 = nullptr;
284 m_reg16 = nullptr;
285
286 switch(m_reg)
287 {
288 case M6809_A:
289 set_regop8(m_q.r.a);
290 break;
291 case M6809_B:
292 set_regop8(m_q.r.b);
293 break;
294 case M6809_D:
295 set_regop16(m_q.p.d);
296 break;
297 case M6809_X:
298 set_regop16(m_x);
299 break;
300 case M6809_Y:
301 set_regop16(m_y);
302 break;
303 case M6809_U:
304 set_regop16(m_u);
305 break;
306 case M6809_S:
307 set_regop16(m_s);
308 break;
309 }
310 }
311
312
313 //-------------------------------------------------
314 // memory_space_config - return the configuration
315 // of the specified address space, or nullptr if
316 // the space doesn't exist
317 //-------------------------------------------------
318
memory_space_config() const319 device_memory_interface::space_config_vector m6809_base_device::memory_space_config() const
320 {
321 if(has_configured_map(AS_OPCODES))
322 return space_config_vector {
323 std::make_pair(AS_PROGRAM, &m_program_config),
324 std::make_pair(AS_OPCODES, &m_sprogram_config)
325 };
326 else
327 return space_config_vector {
328 std::make_pair(AS_PROGRAM, &m_program_config)
329 };
330 }
331
332
333 //-------------------------------------------------
334 // state_import - import state into the device,
335 // after it has been set
336 //-------------------------------------------------
337
state_import(const device_state_entry & entry)338 void m6809_base_device::state_import(const device_state_entry &entry)
339 {
340 switch (entry.index())
341 {
342 case M6809_PC:
343 m_ppc.w = m_pc.w;
344 break;
345
346 case STATE_GENPCBASE:
347 m_pc.w = m_ppc.w;
348 break;
349 }
350 }
351
352 //-------------------------------------------------
353 // state_string_export - export state as a string
354 // for the debugger
355 //-------------------------------------------------
356
state_string_export(const device_state_entry & entry,std::string & str) const357 void m6809_base_device::state_string_export(const device_state_entry &entry, std::string &str) const
358 {
359 switch (entry.index())
360 {
361 case STATE_GENFLAGS:
362 str = string_format("%c%c%c%c%c%c%c%c",
363 (m_cc & 0x80) ? 'E' : '.',
364 (m_cc & 0x40) ? 'F' : '.',
365 (m_cc & 0x20) ? 'H' : '.',
366 (m_cc & 0x10) ? 'I' : '.',
367 (m_cc & 0x08) ? 'N' : '.',
368 (m_cc & 0x04) ? 'Z' : '.',
369 (m_cc & 0x02) ? 'V' : '.',
370 (m_cc & 0x01) ? 'C' : '.');
371 break;
372 }
373 }
374
375
376 //-------------------------------------------------
377 // disassemble - call the disassembly
378 // helper function
379 //-------------------------------------------------
380
create_disassembler()381 std::unique_ptr<util::disasm_interface> m6809_base_device::create_disassembler()
382 {
383 return std::make_unique<m6809_disassembler>();
384 }
385
386
387 //**************************************************************************
388 // CORE EXECUTION LOOP
389 //**************************************************************************
390
391 //-------------------------------------------------
392 // execute_clocks_to_cycles - convert the raw
393 // clock into cycles per second
394 //-------------------------------------------------
395
execute_clocks_to_cycles(uint64_t clocks) const396 uint64_t m6809_base_device::execute_clocks_to_cycles(uint64_t clocks) const noexcept
397 {
398 return (clocks + m_clock_divider - 1) / m_clock_divider;
399 }
400
401
402 //-------------------------------------------------
403 // execute_cycles_to_clocks - convert a cycle
404 // count back to raw clocks
405 //-------------------------------------------------
406
execute_cycles_to_clocks(uint64_t cycles) const407 uint64_t m6809_base_device::execute_cycles_to_clocks(uint64_t cycles) const noexcept
408 {
409 return cycles * m_clock_divider;
410 }
411
412
413 //-------------------------------------------------
414 // execute_min_cycles - return minimum number of
415 // cycles it takes for one instruction to execute
416 //-------------------------------------------------
417
execute_min_cycles() const418 uint32_t m6809_base_device::execute_min_cycles() const noexcept
419 {
420 return 1;
421 }
422
423
424 //-------------------------------------------------
425 // execute_max_cycles - return maximum number of
426 // cycles it takes for one instruction to execute
427 //-------------------------------------------------
428
execute_max_cycles() const429 uint32_t m6809_base_device::execute_max_cycles() const noexcept
430 {
431 return 19;
432 }
433
434
435 //-------------------------------------------------
436 // execute_input_lines - return the number of
437 // input/interrupt lines
438 //-------------------------------------------------
439
execute_input_lines() const440 uint32_t m6809_base_device::execute_input_lines() const noexcept
441 {
442 return 3;
443 }
444
445
446 //-------------------------------------------------
447 // execute_set_input - act on a changed input/
448 // interrupt line
449 //-------------------------------------------------
450
execute_set_input(int inputnum,int state)451 void m6809_base_device::execute_set_input(int inputnum, int state)
452 {
453 if (LOG_INTERRUPTS)
454 logerror("%s: inputnum=%s state=%d totalcycles=%d\n", machine().describe_context(), inputnum_string(inputnum), state, (int) attotime_to_clocks(machine().time()));
455
456 switch(inputnum)
457 {
458 case INPUT_LINE_NMI:
459 // NMI is edge triggered
460 m_nmi_asserted = m_nmi_asserted || ((state != CLEAR_LINE) && !m_nmi_line && m_lds_encountered);
461 m_nmi_line = (state != CLEAR_LINE);
462 break;
463
464 case M6809_FIRQ_LINE:
465 // FIRQ is line triggered
466 m_firq_line = (state != CLEAR_LINE);
467 break;
468
469 case M6809_IRQ_LINE:
470 // IRQ is line triggered
471 m_irq_line = (state != CLEAR_LINE);
472 break;
473 }
474 }
475
476
477 //-------------------------------------------------
478 // inputnum_string
479 //-------------------------------------------------
480
inputnum_string(int inputnum)481 const char *m6809_base_device::inputnum_string(int inputnum)
482 {
483 switch(inputnum)
484 {
485 case INPUT_LINE_NMI: return "NMI";
486 case M6809_FIRQ_LINE: return "FIRQ";
487 case M6809_IRQ_LINE: return "IRQ";
488 default: return "???";
489 }
490 }
491
492
493 //-------------------------------------------------
494 // read_exgtfr_register
495 //-------------------------------------------------
496
read_exgtfr_register(uint8_t reg)497 m6809_base_device::exgtfr_register m6809_base_device::read_exgtfr_register(uint8_t reg)
498 {
499 exgtfr_register result;
500 result.byte_value = 0xFF;
501 result.word_value = 0x00FF;
502
503 switch(reg & 0x0F)
504 {
505 case 0: result.word_value = m_q.r.d; break; // D
506 case 1: result.word_value = m_x.w; break; // X
507 case 2: result.word_value = m_y.w; break; // Y
508 case 3: result.word_value = m_u.w; break; // U
509 case 4: result.word_value = m_s.w; break; // S
510 case 5: result.word_value = m_pc.w; break; // PC
511 case 8: result.byte_value = m_q.r.a; break; // A
512 case 9: result.byte_value = m_q.r.b; break; // B
513 case 10: result.byte_value = m_cc; break; // CC
514 case 11: result.byte_value = m_dp; break; // DP
515 }
516 return result;
517 }
518
519
520 //-------------------------------------------------
521 // write_exgtfr_register
522 //-------------------------------------------------
523
write_exgtfr_register(uint8_t reg,m6809_base_device::exgtfr_register value)524 void m6809_base_device::write_exgtfr_register(uint8_t reg, m6809_base_device::exgtfr_register value)
525 {
526 switch(reg & 0x0F)
527 {
528 case 0: m_q.r.d = value.word_value; break; // D
529 case 1: m_x.w = value.word_value; break; // X
530 case 2: m_y.w = value.word_value; break; // Y
531 case 3: m_u.w = value.word_value; break; // U
532 case 4: m_s.w = value.word_value; break; // S
533 case 5: m_pc.w = value.word_value; break; // PC
534 case 8: m_q.r.a = value.byte_value; break; // A
535 case 9: m_q.r.b = value.byte_value; break; // B
536 case 10: m_cc = value.byte_value; break; // CC
537 case 11: m_dp = value.byte_value; break; // DP
538 }
539 }
540
541
542 //-------------------------------------------------
543 // log_illegal - used to log hits to illegal
544 // instructions (except for HD6309 which traps)
545 //-------------------------------------------------
546
log_illegal()547 void m6809_base_device::log_illegal()
548 {
549 logerror("%s: illegal opcode at %04x\n", machine().describe_context(), (unsigned) m_pc.w);
550 }
551
552
553 //-------------------------------------------------
554 // execute_one - try to execute a single instruction
555 //-------------------------------------------------
556
execute_one()557 void m6809_base_device::execute_one()
558 {
559 switch(pop_state())
560 {
561 #include "cpu/m6809/m6809.hxx"
562 }
563 }
564
565
566 //-------------------------------------------------
567 // execute_run - execute a timeslice's worth of
568 // opcodes
569 //-------------------------------------------------
570
execute_run()571 void m6809_base_device::execute_run()
572 {
573 do
574 {
575 execute_one();
576 } while(m_icount > 0);
577 }
578
579
read(uint16_t adr)580 uint8_t m6809_base_device::mi_default::read(uint16_t adr)
581 {
582 return program.read_byte(adr);
583 }
584
read_opcode(uint16_t adr)585 uint8_t m6809_base_device::mi_default::read_opcode(uint16_t adr)
586 {
587 return csprogram.read_byte(adr);
588 }
589
read_opcode_arg(uint16_t adr)590 uint8_t m6809_base_device::mi_default::read_opcode_arg(uint16_t adr)
591 {
592 return cprogram.read_byte(adr);
593 }
594
595
write(uint16_t adr,uint8_t val)596 void m6809_base_device::mi_default::write(uint16_t adr, uint8_t val)
597 {
598 program.write_byte(adr, val);
599 }
600
601
602
603 //-------------------------------------------------
604 // mc6809_device
605 //-------------------------------------------------
606
mc6809_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)607 mc6809_device::mc6809_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
608 : m6809_base_device(mconfig, tag, owner, clock, MC6809, 4)
609 {
610 }
611
612
613
614 //-------------------------------------------------
615 // mc6809e_device
616 //-------------------------------------------------
617
mc6809e_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)618 mc6809e_device::mc6809e_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
619 : m6809_base_device(mconfig, tag, owner, clock, MC6809E, 1)
620 {
621 }
622
623
624
625 //-------------------------------------------------
626 // m6809_device
627 //-------------------------------------------------
628
m6809_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)629 m6809_device::m6809_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
630 : m6809_base_device(mconfig, tag, owner, clock, M6809, 1)
631 {
632 }
633