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serintr.s@ c65a0e2

Last change on this file since c65a0e2 was c65a0e2, 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 .equ $00000400 * Beginning of system RAM area <==
43	*
44	SR1IOREC .equ RAM+$0AB0 * Serial-1 iorec structure <==
45	SR2IOREC .equ RAM+$0AD8 * Serial-2 iorec structure <==
46	MC1IOREC .equ RAM+$0B00 * MIDI-1 iorec structure <==
47	MC2IOREC .equ RAM+$0B28 * MIDI-2 iorec structure <==
48	*
49	* End of bios version dependent addresses.
50	*
51	* ==============================================================================
52	*
53	.page
54	*
55	SERVECT .equ $000074 * Level 5 interrupt autovector address
56	*
57	IPL7 .equ $0700 * IPL 7 value for sr
58	*
59	* ACIA I/O Addresses:
60	* -------------------
61	SR1ACIA .equ $3A8001 * Serial-1 ACIA base address
62	SR2ACIA .equ $3A8009 * Serial-2 ACIA base address
63	MC1ACIA .equ $3AC001 * MIDI-1 ACIA base address
64	MC2ACIA .equ $3AC009 * MIDI-2 ACIA base address
65	*
66	* ACIA Register offsets:
67	* ----------------------
68	ACIA_IER .equ 0 * ACIA IER offset
69	ACIA_ISR .equ 0 * ACIA ISR offset
70	ACIA_CSR .equ 2 * ACIA CSR offset
71	ACIA_CFR .equ 2 * ACIA CFR offset
72	ACIA_TBR .equ 4 * ACIA TBR offset
73	ACIA_TDR .equ 6 * ACIA TDR offset
74	ACIA_RDR .equ 6 * ACIA RDR offset
75	*
76	* iorec structure definitions:
77	* ----------------------------
78	IORECLN .equ 40 * Length of an iorec structure
79	*
80	ibuf .equ 0 * Input buffer base address
81	ibufsize .equ 4 * Input buffer size (bytes)
82	ibufhd .equ 6 * Input buffer head index
83	ibuftl .equ 8 * Input buffer tail index
84	ibuflow .equ 10 * Input buffer low water mark
85	ibufhi .equ 12 * Input buffer high water mark
86	obuf .equ 14 * Output buffer base address
87	obufsize .equ 18 * Output buffer size (bytes)
88	obufhd .equ 20 * Output buffer head index
89	obuftl .equ 22 * Output buffer tail index
90	obuflow .equ 24 * Output buffer low water mark
91	obufhi .equ 26 * Output buffer high water mark
92	cfr0 .equ 28 * ACIA CFR, MS bit = 0
93	cfr1 .equ 29 * ACIA CFR, MS bit = 1
94	flagxon .equ 30 * XON flag (non-zero = XOFF sent)
95	flagxoff .equ 31 * XOFF flag (non-zero = active)
96	linedisc .equ 32 * Line discipline flags
97	erbyte .equ 33 * Last error byte
98	isr .equ 34 * ACIA ISR on interrupt
99	csr .equ 35 * ACIA CSR on interrupt
100	errct .equ 36 * Error count (FRM/OVR/BRK)
101	ibfct .equ 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 #$11,d0 * Is this an XON ?
219	bne serrx2 * Jump if not
220	*
221	move.b #$00,flagxoff(a0) * Clear flagxoff
222	bra sertxq * Done
223	*
224	serrx2: cmpi.b #$13,d0 * Is this an XOFF ?
225	bne serrx3 * Jump if not
226	*
227	move.b #$FF,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 #$FF,flagxon(a0) * Set the flag
260	move.b #$13,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 #$FFFE,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 #$0001,sr * Set carry flag = buffer full
405	rts * Return to caller
406	*
407	.page
408	*
409	* midput -- Output to MIDI
410	* ------ --------------
411	midput: move.w sr,-(a7) * Save status register
412	ori.w #IPL7,sr * DISABLE INTERRUPTS
413	move.b ACIA_ISR(a1),isr(a0) * Get ACIA isr
414	move.b ACIA_CSR(a1),csr(a0) * Get ACIA csr
415	btst.b #6,isr(a0) * Is ACIA still sending ?
416	beq midpt_2 * Jump if so
417	*
418	move.w obufhd(a0),d2 * Head index to d2
419	cmp.w obuftl(a0),d2 * Compare to tail index
420	bne midpt_2 * Jump if buffer not empty
421	*
422	move.b d1,ACIA_TDR(a1) * Give byte to ACIA to send
423	bra midpt_3 * Go set final status and exit
424	*
425	midpt_2: move.w obuftl(a0),d2 * Tail index to d2
426	bsr wrapout * Adjust for wraparound
427	cmp.w obufhd(a0),d2 * Compare to head index
428	beq midpt_4 * Jump if buffer full
429	*
430	move.l obuf(a0),a2 * Get buffer base address in a2
431	move.b d1,0(a2,d2) * Put character in buffer
432	move.w d2,obuftl(a0) * Update buffer tail index
433	*
434	midpt_3: bsr midchk * Check status on our way out
435	move.w (a7)+,sr * RESTORE INTERRUPTS
436	andi #$FFFE,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 #$0001,sr * Set carry flag = buffer full
442	rts * Return to caller
443	*
444	.page
445	*
446	* rtschk -- Check RTS mode and turn on RTS if it's enabled
447	* ------ ----------------------------------------------
448	rtschk: btst #1,linedisc(a0) * RTS/CTS mode set ?
449	beq rtsexit * Jump to exit if not
450	*
451	* rtson -- Turn on RTS line
452	* ----- ----------------
453	rtson: move.b cfr1(a0),d0 * Pick up CFR1 image
454	bclr #0,d0 * Turn on RTS line (0 = on)
455	bra rtscmn * Join common RTS code below
456	*
457	* rtsoff -- Turn off RTS line
458	* ------ -----------------
459	rtsoff: move.b cfr1(a0),d0 * Pick up CFR1 image
460	bset #0,d0 * Turn off RTS line (1 = off)
461
462	rtscmn: bset #7,d0 * Make sure MS bit is set
463	move.b d0,cfr1(a0) * Update CFR1 image
464	move.b d0,ACIA_CFR(a1) * Send CFR to hardware
465	*
466	rtsexit: rts * Return to caller
467	*
468	.page
469	*
470	* wrapin -- Check input pointer for wraparound
471	* ------ ----------------------------------
472	wrapin: add.w #1,d1 * Head index +1
473	cmp.w ibufsize(a0),d1 * = buffer size ?
474	bcs wrapin1 * Jump if not
475	*
476	moveq.l #0,d1 * Wraparound
477	*
478	wrapin1: rts * Return to caller
479	*
480	* wrapout -- Check output pointer for wraparound
481	* ------- -----------------------------------
482	wrapout: addq.w #1,d2 * Tail index +1
483	cmp.w obufsize(a0),d2 * = buffer size ?
484	bcs wrapout1 * Jump if not
485	*
486	moveq.l #0,d2 * Wrap around if so
487	*
488	wrapout1: rts * Return to caller
489	*
490	.page
491	*
492	* _setsio -- setsio() -- initialize serial I/O vectors and DCD interrupts
493	* ------- ------------------------------------------------------------
494	_setsio: move.w sr,-(a7) * Preserve status register
495	ori.w #$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 #$90,ACIA_IER(a1) * Enable DCD interrupts
505	*
506	lea SR2ACIA,a1 * Point at Serial-2 ACIA
507	move.b #$90,ACIA_IER(a1) * Enable DCD interrupts
508	*
509	lea MC1ACIA,a1 * Point at MIDI-1 ACIA
510	move.b #$90,ACIA_IER(a1) * Enable DCD interrupts
511	*
512	lea MC2ACIA,a1 * Point at MIDI-2 ACIA
513	move.b #$90,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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