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serintr.s

Last change on this file was 8325447, checked in by Thomas Lopatic <thomas@…>, 7 years ago
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1	\| ------------------------------------------------------------------------------
2	\| serintr.s -- MIDAS-VII serial I/O subroutines
3	\| Version 4 -- 1988-12-13 -- D.N. Lynx Crowe
4
5	\| These subroutines replace those in bios.s in order to add support for
6	\| MIDAS-VII foot pedal and pulse inputs, and pulse outputs.
7
8	\| WARNING: The code below uses addresses in the bios RAM area. These addresses
9	\| correspond to those in PROMS dated 1988-06-20 et seq. If the bios is changed,
10	\| the addresses marked with <== may have to be changed.
11	\| ------------------------------------------------------------------------------
12
13	.text
14
15	.xdef setsio
16
17	.xdef foot1
18	.xdef foot2
19	.xdef pulse1
20	.xdef pulse2
21
22	.xdef serintr
23
24	.xdef serint
25	.xdef midint
26
27	.xdef wrapin
28	.xdef wrapout
29
30	.xdef serput
31	.xdef midput
32
33	.xdef rtschk
34
35	.xdef rtson
36	.xdef rtsoff
37
38	\| ==============================================================================
39
40	\| The following addresses, marked by <==, are bios version dependent:
41
42	RAM = 0x00000400 \| Beginning of system RAM area <==
43
44	SR1IOREC = RAM+0x0AB0 \| Serial-1 iorec structure <==
45	SR2IOREC = RAM+0x0AD8 \| Serial-2 iorec structure <==
46	MC1IOREC = RAM+0x0B00 \| MIDI-1 iorec structure <==
47	MC2IOREC = RAM+0x0B28 \| MIDI-2 iorec structure <==
48
49	\| End of bios version dependent addresses.
50
51	\| ==============================================================================
52
53	.page
54
55	SERVECT = 0x000074 \| Level 5 interrupt autovector address
56
57	IPL7 = 0x0700 \| IPL 7 value for sr
58
59	\| ACIA I/O Addresses:
60	\| -------------------
61	SR1ACIA = 0x3A8001 \| Serial-1 ACIA base address
62	SR2ACIA = 0x3A8009 \| Serial-2 ACIA base address
63	MC1ACIA = 0x3AC001 \| MIDI-1 ACIA base address
64	MC2ACIA = 0x3AC009 \| MIDI-2 ACIA base address
65
66	\| ACIA Register offsets:
67	\| ----------------------
68	ACIA_IER = 0 \| ACIA IER offset
69	ACIA_ISR = 0 \| ACIA ISR offset
70	ACIA_CSR = 2 \| ACIA CSR offset
71	ACIA_CFR = 2 \| ACIA CFR offset
72	ACIA_TBR = 4 \| ACIA TBR offset
73	ACIA_TDR = 6 \| ACIA TDR offset
74	ACIA_RDR = 6 \| ACIA RDR offset
75
76	\| iorec structure definitions:
77	\| ----------------------------
78	IORECLN = 40 \| Length of an iorec structure
79
80	ibuf = 0 \| Input buffer base address
81	ibufsize = 4 \| Input buffer size (bytes)
82	ibufhd = 6 \| Input buffer head index
83	ibuftl = 8 \| Input buffer tail index
84	ibuflow = 10 \| Input buffer low water mark
85	ibufhi = 12 \| Input buffer high water mark
86	obuf = 14 \| Output buffer base address
87	obufsize = 18 \| Output buffer size (bytes)
88	obufhd = 20 \| Output buffer head index
89	obuftl = 22 \| Output buffer tail index
90	obuflow = 24 \| Output buffer low water mark
91	obufhi = 26 \| Output buffer high water mark
92	cfr0 = 28 \| ACIA CFR, MS bit = 0
93	cfr1 = 29 \| ACIA CFR, MS bit = 1
94	flagxon = 30 \| XON flag (non-zero = XOFF sent)
95	flagxoff = 31 \| XOFF flag (non-zero = active)
96	linedisc = 32 \| Line discipline flags
97	erbyte = 33 \| Last error byte
98	isr = 34 \| ACIA ISR on interrupt
99	csr = 35 \| ACIA CSR on interrupt
100	errct = 36 \| Error count (FRM/OVR/BRK)
101	ibfct = 38 \| Input buffer full count
102
103	.page
104
105	\| serintr -- Serial (Serial-1, Serial-2, MIDI-1, MIDI-2) interrupt handler
106	\| ------- -------------------------------------------------------------
107	serintr: movem.l d0-d3/a0-a2,-(a7) \| Save registers
108	lea SR1IOREC,a0 \| Point at Serial-1 iorec
109	lea SR1ACIA,a1 \| Point at Serial-1 ACIA
110	movea.l foot1,a2 \| Point at foot sw. 1 processor
111	bsr serint \| Go process (possible) int.
112
113	lea SR2IOREC,a0 \| Point at Serial-2 iorec
114	lea SR2ACIA,a1 \| Point at Serial-2 ACIA
115	movea.l foot2,a2 \| Point at foot sw. 2 processor
116	bsr serint \| Go process (possible) int.
117
118	lea MC1IOREC,a0 \| Point at MIDI-1 iorec
119	lea MC1ACIA,a1 \| Point at MIDI-1 ACIA
120	movea.l pulse1,a2 \| Point at pulse 1 processor
121	bsr midint \| Go process (possible) int.
122
123	lea MC2IOREC,a0 \| Point at MIDI-2 iorec
124	lea MC2ACIA,a1 \| Point at MIDI-2 ACIA
125	movea.l pulse2,a2 \| Point at pulse 2 processor
126	bsr midint \| Go process (possible) int.
127
128	movem.l (a7)+,d0-d3/a0-a2 \| Restore registers
129	rte \| Return from exception
130
131	.page
132
133	\| serint -- Process an interrupt from Serial-1 or Serial-2
134	\| ------ ----------------------------------------------
135	serint: move.b ACIA_ISR(a1),isr(a0) \| Get and save ISR
136	move.b ACIA_CSR(a1),csr(a0) \| Get and save CSR
137
138	btst.b #7,isr(a0) \| Was int for this device ?
139	beq serintx \| Jump if not
140
141	serchk: btst.b #1,isr(a0) \| FRM/OVR/BRK error ?
142	bne sererr \| Jump if so
143
144	btst.b #0,isr(a0) \| Receiver interrupt ?
145	bne serrx \| Jump if so
146
147	sertxq: btst.b #6,isr(a0) \| Transmitter interrupt ?
148	bne sertx \| Jump if so
149
150	serctq: btst.b #5,isr(a0) \| CTS interrupt ?
151	bne sercts \| Jump if so
152
153	serintx: btst.b #4,isr(a0) \| DCD interrupt ?
154	bne calldcd \| Jump if so
155
156	serdone: rts \| Return to caller
157
158	calldcd: move.b csr(a0),d0 \| Get CSR interrupt status
159	btst.l #4,d0 \| Check DCD input (0 = active)
160	bne calldcd0 \| Jump if line was inactive
161
162	moveq.l #1,d0 \| Set footswitch status to TRUE
163	bra calldcd1 \| ...
164
165	calldcd0: moveq.l #0,d0 \| Set footswitch status to FALSE
166
167	calldcd1: move.w d0,-(a7) \| Call the footswitch processor
168	jsr (a2) \| ... (*footX)(status)
169	tst.w (a7)+ \| ...
170	rts \| Return to caller
171
172	.page
173
174	\| Handle serial I/O port error
175
176	sererr: addq.w #1,errct(a0) \| Update error count
177	move.b ACIA_RDR(a1),erbyte(a0) \| Get error byte
178	rts \| Return to caller
179
180
181	\| Handle CTS interupt
182
183	sercts: btst.b #1,linedisc(a0) \| RTS/CTS mode ?
184	beq serintx \| Ignore if not
185
186	btst.b #5,csr(a0) \| CTS set ?
187	beq serintx \| Ignore if not
188
189	sercts1: btst.b #6,isr(a0) \| TDRE set ?
190	beq sercts1 \| Loop until it is (!)
191
192	move.w obufhd(a0),d2 \| Head index to d2
193	cmp.w obuftl(a0),d2 \| Compare to tail index
194	beq serintx \| Done if buffer empty
195
196	bsr wrapout \| Adjust pointer for wraparound
197	move.l obuf(a0),a2 \| Get buffer base in a2
198	move.b 0(a2,d2),ACIA_TDR(a1) \| Send byte on its way
199	move.w d2,obufhd(a0) \| Save updated head index
200	bra serintx \| Done
201
202	.page
203
204	\| Handle receiver interrupt
205
206	serrx: btst.b #1,linedisc(a0) \| RTS/CTS mode set ?
207	beq serrx1 \| Jump if not
208
209	bsr rtsoff \| Turn off RTS
210
211	serrx1: move.b ACIA_RDR(a1),d0 \| Read data from ACIA
212	btst.b #1,linedisc(a0) \| RTS/CTS mode set ?
213	bne serrx3 \| Jump if so
214
215	btst.b #0,linedisc(a0) \| XON/XOFF mode set ?
216	beq serrx3 \| Jump if not
217
218	cmpi.b #0x11,d0 \| Is this an XON ?
219	bne serrx2 \| Jump if not
220
221	move.b #0x00,flagxoff(a0) \| Clear flagxoff
222	bra sertxq \| Done
223
224	serrx2: cmpi.b #0x13,d0 \| Is this an XOFF ?
225	bne serrx3 \| Jump if not
226
227	move.b #0xFF,flagxoff(a0) \| Set flagxoff
228	bra sertxq \| Done
229
230	serrx3: move.w ibuftl(a0),d1 \| Get tail index in d1
231	bsr wrapin \| Adjust for wraparound
232	cmp.w ibufhd(a0),d1 \| Head = tail ?
233	beq seribf \| If so, we drop the character
234
235	.page
236	move.l ibuf(a0),a2 \| Get buffer address
237	move.b d0,0(a2,d1) \| Stash byte in buffer
238	move.w d1,ibuftl(a0) \| Save updated tail index
239	move.w ibuftl(a0),d2 \| Tail index to d2
240	move.w ibufhd(a0),d3 \| Head index to d3
241	cmp.w d3,d2 \| Head > Tail ?
242	bhi rsi_1 \| Jump if not
243
244	add.w ibufsize(a0),d2 \| Add buffer size to tail index
245
246	rsi_1: sub.w d3,d2 \| Length = (adjusted)Tail - Head
247	cmp.w ibufhi(a0),d2 \| Hit high water mark ?
248	bne serrx4 \| Jump if not
249
250	btst.b #1,linedisc(a0) \| RTS/CTS mode set ?
251	bne sertxq \| Done if so
252
253	btst.b #0,linedisc(a0) \| XON/XOFF mode set ?
254	beq serrx4 \| Jump if not
255
256	tst.b flagxon(a0) \| XOFF already sent ?
257	bne serrx4 \| Jump if so
258
259	move.b #0xFF,flagxon(a0) \| Set the flag
260	move.b #0x13,d1 \| Send an XOFF
261	bsr serput \| ...
262
263	serrx4: btst #1,linedisc(a0) \| RTS/CTS mode set ?
264	beq sertxq \| Done if not
265
266	bsr rtson \| Turn on RTS
267	bra sertxq \| Done
268
269	.page
270
271	\| Handle transmitter interrupt
272
273	sertx: btst.b #1,linedisc(a0) \| RTS/CTS mode set ?
274	bne sertx2 \| If so, go check CTS
275
276	btst.b #0,linedisc(a0) \| XON/XOFF mode set ?
277	beq sertx1 \| Jump if not
278
279	tst.b flagxoff(a0) \| Check flagxoff
280	bne serctq \| Done if set
281
282	sertx1: move.w obufhd(a0),d2 \| Head index to d2
283	cmp.w obuftl(a0),d2 \| Compare to tail index
284	beq serctq \| Done if buffer empty
285
286	bsr wrapout \| Adjust pointer for wraparound
287	move.l obuf(a0),a2 \| Get buffer base address
288	move.b 0(a2,d2),ACIA_TDR(a1) \| Send byte on its way
289	move.w d2,obufhd(a0) \| Save updated head index
290	bra serctq \| Done
291
292	sertx2: btst.b #5,csr(a0) \| CTS set in csr ?
293	beq serctq \| If not, go check for CTS int
294
295	bra sertx1 \| CTS was set, go transmit
296
297	seribf: move.b d0,erbyte(a0) \| Log dropped character
298	addq.w #1,ibfct(a0) \| ...
299	bra sertxq \| Go check Tx interrupt
300
301	.page
302
303	\| midint -- Process an interrupt from MIDI-1 or MIDI-2
304	\| ------ ------------------------------------------
305	midint: move.b ACIA_ISR(a1),isr(a0) \| Get and save ISR
306	move.b ACIA_CSR(a1),csr(a0) \| Get and save CSR
307
308	btst.b #7,isr(a0) \| Was int for this device ?
309	beq midintx \| Jump if not
310
311	midchk: btst.b #1,isr(a0) \| FRM/OVR/BRK error ?
312	bne miderr \| Jump if so
313
314	btst.b #0,isr(a0) \| Receiver interrupt ?
315	bne midrx \| Jump if so
316
317	midtxq: btst.b #6,isr(a0) \| Transmitter interrupt ?
318	bne midtx \| Jump if so
319
320	midintx: btst #4,isr(a0) \| DCD interrupt ?
321	bne mididcd \| Jump if so
322
323	mididone: rts \| Return to caller
324
325	mididcd: jmp (a2) \| Exit through the DCD processor
326
327	miderr: addq.w #1,errct(a0) \| Update error count
328	move.b ACIA_RDR(a1),erbyte(a0) \| Get error byte
329	rts
330
331	\| Handle receiver interrupt
332
333	midrx: move.b ACIA_RDR(a1),d0 \| Read data from ACIA
334	move.w ibuftl(a0),d1 \| Get tail index in d1
335	bsr wrapin \| Adjust for wraparound
336	cmp.w ibufhd(a0),d1 \| Head = tail ?
337	beq midibf \| If so, we drop the character
338
339	move.l ibuf(a0),a2 \| Get buffer address
340	move.b d0,0(a2,d1) \| Stash byte in buffer
341	move.w d1,ibuftl(a0) \| Save updated tail index
342	bra midtxq \| Done (go check tx int)
343
344	.page
345
346	\| Handle transmitter interrupt
347
348	midtx: move.w obufhd(a0),d2 \| Head index to d2
349	cmp.w obuftl(a0),d2 \| Compare to tail index
350	beq midintx \| Done if buffer empty
351
352	bsr wrapout \| Adjust pointer for wraparound
353	move.l obuf(a0),a2 \| Get buffer base address
354	move.b 0(a2,d2),ACIA_TDR(a1) \| Send byte on its way
355	move.w d2,obufhd(a0) \| Save updated head index
356	bra midintx \| Done
357
358	midibf: move.b d0,erbyte(a0) \| Log dropped character
359	addq.w #1,ibfct(a0) \| ...
360	bra midtxq \| Go check Tx interrupt
361
362	.page
363
364	\| serput -- Output a character to a serial port
365	\| ------ -----------------------------------
366	serput: move.w sr,-(a7) \| Save status register
367	ori.w #IPL7,sr \| DISABLE INTERRUPTS
368	move.b ACIA_ISR(a1),isr(a0) \| Get ACIA isr
369	move.b ACIA_CSR(a1),csr(a0) \| Get ACIA csr
370	btst #0,linedisc(a0) \| XON/XOFF mode ?
371	beq serpt_1 \| Jump if not
372
373	tst.b flagxoff(a0) \| XON active ?
374	bne serpt_2 \| Jump if so
375
376	serpt_1: btst.b #6,isr(a0) \| Is ACIA still sending ?
377	beq serpt_2 \| Jump if so
378
379	move.w obufhd(a0),d2 \| Head index to d2
380	cmp.w obuftl(a0),d2 \| Compare to tail index
381	bne serpt_2 \| Jump if buffer not empty
382
383	move.b d1,ACIA_TDR(a1) \| Give byte to ACIA to send
384	bra serpt_3 \| Go deal with RTS/CTS if needed
385
386	serpt_2: move.w obuftl(a0),d2 \| Tail index to d2
387	bsr wrapout \| Adjust for wraparound
388	cmp.w obufhd(a0),d2 \| Compare to head index
389	beq serpt_4 \| Jump if buffer full
390
391	move.l obuf(a0),a2 \| Get buffer base address in a2
392	move.b d1,0(a2,d2) \| Put character in buffer
393	move.w d2,obuftl(a0) \| Update buffer tail index
394
395	serpt_3: bsr serchk \| Check status on our way out
396	bsr rtschk \| Handle RTS protocol
397	move.w (a7)+,sr \| RESTORE INTERRUPTS
398	andi #0xFFFE,sr \| Clear carry flag = OK
399	rts \| Return to caller
400
401	serpt_4: bsr serchk \| Check status on our way out
402	bsr rtschk \| Handle RTS protocol
403	move.w (a7)+,sr \| RESTORE INTERRUPTS
404	ori #0x0001,sr \| Set carry flag = buffer full
405	rts \| Return to caller
406
407	.page
408
409	\| midput -- Output to MIDI
410	\| ------ --------------
411	midput: move.w sr,-(a7) \| Save status register
412	ori.w #IPL7,sr \| DISABLE INTERRUPTS
413	move.b ACIA_ISR(a1),isr(a0) \| Get ACIA isr
414	move.b ACIA_CSR(a1),csr(a0) \| Get ACIA csr
415	btst.b #6,isr(a0) \| Is ACIA still sending ?
416	beq midpt_2 \| Jump if so
417
418	move.w obufhd(a0),d2 \| Head index to d2
419	cmp.w obuftl(a0),d2 \| Compare to tail index
420	bne midpt_2 \| Jump if buffer not empty
421
422	move.b d1,ACIA_TDR(a1) \| Give byte to ACIA to send
423	bra midpt_3 \| Go set final status and exit
424
425	midpt_2: move.w obuftl(a0),d2 \| Tail index to d2
426	bsr wrapout \| Adjust for wraparound
427	cmp.w obufhd(a0),d2 \| Compare to head index
428	beq midpt_4 \| Jump if buffer full
429
430	move.l obuf(a0),a2 \| Get buffer base address in a2
431	move.b d1,0(a2,d2) \| Put character in buffer
432	move.w d2,obuftl(a0) \| Update buffer tail index
433
434	midpt_3: bsr midchk \| Check status on our way out
435	move.w (a7)+,sr \| RESTORE INTERRUPTS
436	andi #0xFFFE,sr \| Clear carry flag = OK
437	rts \| Return to caller
438
439	midpt_4: bsr midchk \| Check status on our way out
440	move.w (a7)+,sr \| RESTORE INTERRUPTS
441	ori #0x0001,sr \| Set carry flag = buffer full
442	rts \| Return to caller
443
444	.page
445
446	\| rtschk -- Check RTS mode and turn on RTS if it's enabled
447	\| ------ ----------------------------------------------
448	rtschk: btst #1,linedisc(a0) \| RTS/CTS mode set ?
449	beq rtsexit \| Jump to exit if not
450
451	\| rtson -- Turn on RTS line
452	\| ----- ----------------
453	rtson: move.b cfr1(a0),d0 \| Pick up CFR1 image
454	bclr #0,d0 \| Turn on RTS line (0 = on)
455	bra rtscmn \| Join common RTS code below
456
457	\| rtsoff -- Turn off RTS line
458	\| ------ -----------------
459	rtsoff: move.b cfr1(a0),d0 \| Pick up CFR1 image
460	bset #0,d0 \| Turn off RTS line (1 = off)
461
462	rtscmn: bset #7,d0 \| Make sure MS bit is set
463	move.b d0,cfr1(a0) \| Update CFR1 image
464	move.b d0,ACIA_CFR(a1) \| Send CFR to hardware
465
466	rtsexit: rts \| Return to caller
467
468	.page
469
470	\| wrapin -- Check input pointer for wraparound
471	\| ------ ----------------------------------
472	wrapin: add.w #1,d1 \| Head index +1
473	cmp.w ibufsize(a0),d1 \| = buffer size ?
474	bcs wrapin1 \| Jump if not
475
476	moveq.l #0,d1 \| Wraparound
477
478	wrapin1: rts \| Return to caller
479
480	\| wrapout -- Check output pointer for wraparound
481	\| ------- -----------------------------------
482	wrapout: addq.w #1,d2 \| Tail index +1
483	cmp.w obufsize(a0),d2 \| = buffer size ?
484	bcs wrapout1 \| Jump if not
485
486	moveq.l #0,d2 \| Wrap around if so
487
488	wrapout1: rts \| Return to caller
489
490	.page
491
492	\| setsio -- setsio() -- initialize serial I/O vectors and DCD interrupts
493	\| ------ ------------------------------------------------------------
494	setsio: move.w sr,-(a7) \| Preserve status register
495	ori.w #IPL7,sr \| DISABLE INTERRUPTS
496
497	lea nulsiox,a0 \| Get null return address
498	move.l a0,foot1 \| Initialize foot1 vector
499	move.l a0,foot2 \| Initialize foot2 vector
500	move.l a0,pulse1 \| Initialize pulse1 vector
501	move.l a0,pulse2 \| Initialize pulse2 vector
502
503	lea SR1ACIA,a1 \| Point at Serial-1 ACIA
504	move.b #0x90,ACIA_IER(a1) \| Enable DCD interrupts
505
506	lea SR2ACIA,a1 \| Point at Serial-2 ACIA
507	move.b #0x90,ACIA_IER(a1) \| Enable DCD interrupts
508
509	lea MC1ACIA,a1 \| Point at MIDI-1 ACIA
510	move.b #0x90,ACIA_IER(a1) \| Enable DCD interrupts
511
512	lea MC2ACIA,a1 \| Point at MIDI-2 ACIA
513	move.b #0x90,ACIA_IER(a1) \| Enable DCD interrupts
514
515	lea serintr,a0 \| Initialize interrupt vector
516	move.l a0,SERVECT \| ... in processor RAM
517
518	move.w (a7)+,sr \| RESTORE INTERRUPTS
519
520	nulsiox: rts \| Return to caller
521
522	.bss
523
524	\| DCD interrupt processor vectors
525	\| -------------------------------
526	foot1: .ds.l 1 \| short (*foot1)();
527	foot2: .ds.l 1 \| short (*foot2)();
528	pulse1: .ds.l 1 \| short (*pulse1)();
529	pulse2: .ds.l 1 \| short (*pulse2)();
530
531	.end

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