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procpfl.s

Last change on this file was 8325447, checked in by Thomas Lopatic <thomas@…>, 7 years ago
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1	\| ------------------------------------------------------------------------------
2	\| procpfl.s -- process pendant functions (sustain release processing)
3	\| Version 8 -- 1988-08-31 -- D.N. Lynx Crowe
4	\| ------------------------------------------------------------------------------
5	.text
6
7	.xdef procpfl
8
9	.xdef _curpf_f \| current function (v/p)
10	.xdef _curpf_l \| current pflist entry
11	.xdef _curpf_t \| current trigger
12
13	.xref irand
14	.xref xgetran
15
16	.xref expbit
17	.xref funcndx
18	.xref pflist
19	.xref pfqhdr
20	.xref prstab
21	.xref ptoftab
22	.xref timemlt
23	.xref trgtab
24	.xref valents
25	.xref vce2grp
26	.xref vce2trg
27	.xref veltab
28
29	.page
30	\| ------------------------------------------------------------------------------
31	\| Register usage
32	\| --------------
33	\| d0 scratch
34	\| d1 FPU function index
35	\| d2 point index from FH_CPT (idfcpt)
36	\| d3 scratch
37	\| d4 jump point number from PT_PAR1 (ippar1)
38	\| d5 scratch
39
40	\| a0 scratch
41	\| a1 function header base
42	\| a2 point table base
43	\| a3 FPU base
44
45	\| ------------------------------------------------------------------------------
46	\| FPU definitions
47	\| ---------------
48
49	UPD_BIT = 0x0001 \| update bit (1 = update)
50	INT_BIT = 0x0002 \| int. bit (0 = disable)
51	RAT_BIT = 0x0004 \| ratio bit (0 = ratio)
52
53	VSUBNBIT = 3 \| new value select bit number
54	VAL_BITS = 0x0018 \| new value select bit mask
55
56	MSK_RNVB = 0x000C \| new value / ratio bits
57	MSK_ONVB = 0x0010 \| old new value bit
58
59	FKILL = 0x0014 \| kill value for function
60	FSEND = 0x0015 \| send new value to function
61
62	CLREXP = 0x8000 \| clear value for time exponent
63	CLRMNT = 0x8000 \| clear value for time mantissa
64
65	\| ------------------------------------------------------------------------------
66	\| Miscellaneous definitions
67	\| -------------------------
68
69	PCHMAX = 21920 \| maximum pitch value
70	VALMAX = 32000 \| maximum value to send to FPU
71	VALMIN = -32000 \| minimum value to send to FPU
72
73	LSPCH = 2 \| left shift for sources to freq
74
75	VALLEN = 10 \| length of the 'valent' struct
76	VT_VAL = 8 \| value offset in 'valent'
77
78	.page
79	\| ------------------------------------------------------------------------------
80	\| FPU addresses
81	\| -------------
82
83	FPUBASE = 0x180000 \| FPU base address
84
85	FPUWST = FPUBASE \| FPU waveshape base
86	FPUFUNC = FPUBASE+0x4000 \| FPU function base
87	FPUINT1 = FPUBASE+0x4000 \| FPU int. input address (R/O)
88	FPUINT2 = FPUBASE+0x6000 \| FPU int. reset address (W/O)
89	FPUCFG = FPUBASE+0x5FE0 \| FPU config. data address (W/O)
90
91	F_CTL = 0x00 \| control word
92	F_VAL10 = 0x02 \| new value "10"
93	F_CV1 = 0x08 \| control voltage 1
94	F_SF1 = 0x0A \| scale factor 1
95	F_CV2 = 0x0C \| control voltage 2
96	F_SF2 = 0x0E \| scale factor 2
97	F_CV3 = 0x10 \| control voltage 3
98	F_SF3 = 0x12 \| scale factor 3
99	F_MNT = 0x14 \| time mantissa
100	F_EXP = 0x16 \| time exponent
101	F_VAL01 = 0x1C \| new value "01"
102
103	P_FREQ1 = 0x0020 \| frequency 1
104	P_FREQ2 = 0x0060 \| frequency 2
105	P_FREQ3 = 0x00A0 \| frequency 3
106	P_FREQ4 = 0x00E0 \| frequency 4
107	P_FILTER = 0x0140 \| filter
108	P_FILTRQ = 0x00C0 \| filter q
109
110	P_INDEX1 = 0x0120 \| index 1
111	P_INDEX2 = 0x0160 \| index 2
112	P_INDEX3 = 0x0180 \| index 3
113	P_INDEX4 = 0x01A0 \| index 4
114	P_INDEX5 = 0x01C0 \| index 5
115	P_INDEX6 = 0x01E0 \| index 6
116
117	P_LEVEL = 0x0040 \| level
118
119	P_LOCN = 0x0080 \| location
120	P_DYNAM = 0x0100 \| dynamics
121
122	.page
123	\| ------------------------------------------------------------------------------
124	\| Structure definitions
125	\| ------------------------------------------------------------------------------
126	\| The following MUST match the idfnhdr structure definition in instdsp.h:
127
128	FH_LEN = 12 \| length of the idfnhdr structure
129
130	FH_PCH = 0 \| WORD - pitch offset
131	FH_MLT = 2 \| WORD - overall value multiplier
132	FH_SRC = 4 \| BYTE - overall value source
133	FH_PIF = 5 \| BYTE - # of points in the function
134	FH_PT1 = 6 \| BYTE - index of first point
135	FH_TMD = 7 \| BYTE - trigger mode / control bits
136	FH_CPT = 8 \| BYTE - current point
137	FH_PRM = 9 \| BYTE - misc. function parameter
138	FH_TRG = 10 \| WORD - trigger
139
140	I_ACTIVE = 1 \| 'Active' bit number (in FH_TMD)
141
142	MSK_CTL = 0x001C \| mask for FPU hardware bits (in FH_TMD)
143
144	\| ------------------------------------------------------------------------------
145	\| The following MUST match the instpnt structure definition in instdsp.h:
146
147	PT_LEN = 12 \| length of the instpnt structure
148
149	PT_TIM = 0 \| WORD - time (packed)
150	PT_VAL = 2 \| WORD - value
151	PT_VMLT = 4 \| WORD - value multiplier
152	PT_VSRC = 6 \| BYTE - value source
153	PT_ACT = 7 \| BYTE - action
154	PT_PAR1 = 8 \| BYTE - parameter 1
155	PT_PAR2 = 9 \| BYTE - parameter 2
156	PT_PAR3 = 10 \| BYTE - parameter 3
157	PT_PAD = 11 \| BYTE - padding for even boundary
158
159	MSK_MNT = 0xFFF0 \| mask for mantissa (in PT_TIM)
160	MSK_EXP = 0x000F \| mask for exponent (in PT_TIM)
161
162	MAX_ACT = 7 \| maximum action code value
163
164	\| ------------------------------------------------------------------------------
165	\| Source definitions -- must match those in 'smdefs.h'
166
167	SM_RAND = 1 \| random
168	SM_PTCH = 5 \| pitch
169	SM_KPRS = 6 \| key pressure
170	SM_KVEL = 7 \| key velocity
171	SM_FREQ = 10 \| frequency
172
173	.page
174
175	\| Layout of pflist entries 32 bytes each
176	\| ------------------------
177	PF_NEXT = 0 \| LONG - next entry pointer
178	PF_TRIG = 4 \| WORD - trigger number
179	PF_FUNC = 6 \| WORD - fpuifnc value
180	PF_D1 = 8 \| LONG - d1
181	PF_D2 = 12 \| LONG - d2
182	PF_D4 = 16 \| LONG - d4
183	PF_A1 = 20 \| LONG - a1
184	PF_A2 = 24 \| LONG - a2
185	PF_A3 = 28 \| LONG - a3
186
187	\| Parameter offset
188	\| ----------------
189	TRIG = 8 \| WORD - trigger number
190
191	\| Register equates
192	\| ----------------
193	RCUR = a4 \| current pflist entry pointer
194	RPRV = a5 \| previous pflist entry pointer
195
196	.page
197	\| ------------------------------------------------------------------------------
198	\| procpfl() -- process pendant functions
199
200	\| void
201	\| procpfl(trig);
202	\| unsigned trig;
203
204	\| Processes pendant (sustained) functions by restarting them
205	\| when the trigger (trig) that's sustaining them is released.
206	\| Invoked by key release processing in msm() and localkb().
207
208	\| ------------------------------------------------------------------------------
209
210	procpfl: nop \| FOR DEBUGGING PATCH
211
212	link a6,#0 \| allocate stack frame
213	movem.l d3-d7/a3-a5,-(a7) \| preserve registers we use
214
215	move.w sr,d7 \| save interrupt state
216	move.w #0x2200,sr \| turn off FPU interrupts
217
218	move.w TRIG(a6),d6 \| get trigger we're processing
219	move.w d6,_curpf_t \| ...
220	movea.l #pflist,RPRV \| point at 'previous' pflist entry
221	bra pfscan \| go scan the chain
222
223	pfpass: movea.l RCUR,RPRV \| point at previous entry
224
225	pfscan: move.l (RPRV),d5 \| get next pflist entry pointer
226	beq pfexit \| done if no more
227
228	movea.l d5,RCUR \| point at current entry
229	move.l d5,_curpf_l \| ...
230
231	cmp.w PF_TRIG(RCUR),d6 \| see if this entry is wanted
232	bne pfpass \| jump if not
233
234	movem.l PF_D1(RCUR),d1-d2/d4/a1-a3 \| restore processing state
235	move.w PF_FUNC(RCUR),_curpf_f \| ...
236
237	btst #I_ACTIVE,FH_TMD(a1) \| see if function is active
238	bne doact \| continue function if so
239
240	bra stopfn \| stop function if not
241
242	pfnext: move.l (RCUR),(RPRV) \| remove entry from pflist
243	move.l pfqhdr,(RCUR) \| chain entry to free list
244	move.l RCUR,pfqhdr \| ...
245	bra pfscan \| go look at next entry
246
247	pfexit: move.w d7,sr \| restore interrupt level
248	movem.l (a7)+,d3-d7/a3-a5 \| restore the registers we used
249	unlk a6 \| deallocate stack frame
250	rts \| return to caller
251
252	.page
253
254	\| ------------------------------------------------------------------------------
255	\| stop a function
256	\| ------------------------------------------------------------------------------
257	stopfn: move.b FH_TMD(a1),d0 \| get function control bits
258	andi.w #MSK_RNVB,d0 \| mask for ratio / new new-value bit
259	move.w d0,d3 \| isolate new new-value bit
260	add.w d3,d3 \| ... from function header
261	andi.w #MSK_ONVB,d3 \| ... shift to old new-value bit
262	or.w d3,d0 \| ... and put new bit in old bit
263	move.w d0,F_CTL(a3,d1.W) \| stop the function
264	bclr #I_ACTIVE,FH_TMD(a1) \| reset the active bit
265	bra pfnext \| go restore registers and exit
266
267	\| ------------------------------------------------------------------------------
268	\| setup for and dispatch to the proper action handler
269	\| ------------------------------------------------------------------------------
270	doact: clr.w d2 \| get current point index in d2
271	move.b FH_CPT(a1),d2 \| ...
272	lsl.w #2,d2 \| multiply it by the length of a point
273	move.w d2,d0 \| ... (fast multiply by PT_LEN = 12
274	add.w d2,d2 \| ... via shift and add)
275	add.w d0,d2 \| ...
276	clr.w d4 \| get jump point # into d4
277	move.b PT_PAR1(a2,d2.W),d4 \| ...
278	clr.w d3 \| get action code in d3
279	move.b PT_ACT(a2,d2.W),d3 \| ...
280	cmpi.b #MAX_ACT,d3 \| check against the limit
281	bgt stopfn \| stop things if it's a bad action code
282
283	lsl.w #2,d3 \| develop index to action dispatch table
284	lea actab,a0 \| get the address of the action handler
285	movea.l 0(a0,d3.W),a0 \| ...
286
287	\| ------------------------------------------------------------------------------
288	\| At this point we're ready to do the action associated with the point,
289	\| and the registers are set up, and will remain, as follows:
290
291	\| d1 FPU function index a1 function header base
292	\| d2 point table index a2 point table base
293	\| a3 FPU function base
294	\| d4 jump point number
295
296	\| d0, d3, d5, and a0 are used as scratch throughout the code.
297
298	\| ------------------------------------------------------------------------------
299
300	jmp (a0) \| dispatch to action handler
301
302	.page
303	\| ------------------------------------------------------------------------------
304	\| act0 -- AC_NULL -- no action
305	\| ---- --------------------
306	act0: move.b FH_PT1(a1),d0 \| get first point number
307	add.b FH_PIF(a1),d0 \| add number of points in function
308	subq.b #1,d0 \| make it last point number
309	cmp.b FH_CPT(a1),d0 \| see if we're at the last point
310	beq stopfn \| stop function if so
311
312	addq.b #1,FH_CPT(a1) \| update function header for next point
313	addi.w #PT_LEN,d2 \| advance the point index
314
315	\| ------------------------------------------------------------------------------
316	\| outseg -- output a segment
317	\| ------ ----------------
318	outseg: move.w PT_TIM(a2,d2.w),d3 \| get packed time
319	move.w d3,d0 \| extract mantissa
320	andi.w #MSK_MNT,d0 \| ...
321	mulu timemlt,d0 \| multiply by panel time pot value
322	lsr.l #8,d0 \| ... and scale it
323	lsr.l #7,d0 \| ...
324	move.w d0,F_MNT(a3,d1.W) \| send mantissa to FPU
325	andi.w #MSK_EXP,d3 \| extract exponent code
326	add.w d3,d3 \| look up decoded exponent
327	lea expbit,a0 \| ... in expbit
328	move.w 0(a0,d3.W),F_EXP(a3,d1.W) \| send exponent to FPU
329	move.w PT_VAL(a2,d2.W),d3 \| get the function value
330
331	.page
332	\| ------------------------------------------------------------------------------
333	\| get the point source, if any
334	\| ------------------------------------------------------------------------------
335	tst.w PT_VMLT(a2,d2.W) \| see if we have a point mlt.
336	beq nosrc \| don't do anything for zero
337
338	clr.w d0 \| get the source number
339	move.b PT_VSRC(a2,d2.W),d0 \| ...
340	beq nosrc \| don't do anything for zero
341
342	\| ------------------------------------------------------------------------------
343	\| SM_RAND -- random
344	\| ------------------------------------------------------------------------------
345	cmpi.w #SM_RAND,d0 \| is this the random source ?
346	bne srctyp0 \| jump if not
347
348	movem.l d1-d2/a0-a2,-(a7) \| preserve registers around call
349	move.w PT_VMLT(a2,d2.W),-(a7) \| pass multiplier to xgetran()
350	jsr xgetran \| call for a random number
351	tst.w (a7)+ \| clean up stack
352	movem.l (a7)+,d1-d2/a0-a2 \| restore registers
353	move.w d0,d5 \| put random value in the value register
354	bra applym \| go apply the multiplier
355
356	.page
357	\| ------------------------------------------------------------------------------
358	\| SM_FREQ -- frequency
359	\| ------------------------------------------------------------------------------
360	srctyp0: cmpi.w #SM_FREQ,d0 \| is this the frequency source ?
361	bne srctyp1 \| jump if not
362
363	move.w (a1),d0 \| get the pitch
364	lsr.w #6,d0 \| shift to a word index
365	andi.w #0x01FE,d0 \| mask out extraneous bits
366	lea ptoftab,a0 \| get entry from ptoftab[]
367	move.w 0(a0,d0.W),d5 \| ...
368	bra applym \| go apply the multiplier
369
370	\| ------------------------------------------------------------------------------
371	\| SM_PTCH -- pitch
372	\| ------------------------------------------------------------------------------
373	srctyp1: cmpi.w #SM_PTCH,d0 \| is this the pitch source ?
374	bne srctyp2 \| jump if not
375
376	move.w (a1),d5 \| get the pitch as the value
377	bra applym \| go apply the multiplier
378
379	\| ------------------------------------------------------------------------------
380	\| SM_KVEL -- velocity
381	\| ------------------------------------------------------------------------------
382	srctyp2: cmpi.w #SM_KVEL,d0 \| is this the key velocity source ?
383	bne srctyp3 \| jump if not
384
385	move.w FH_TRG(a1),d0 \| get the trigger number
386	add.w d0,d0 \| ... as a word index
387	lea veltab,a0 \| ... into veltab[]
388	move.w 0(a0,d0.W),d5 \| get the velocity from veltab[trg]
389	bra applym \| go apply the multiplier
390
391	\| ------------------------------------------------------------------------------
392	\| SM_KPRS -- pressure
393	\| ------------------------------------------------------------------------------
394	srctyp3: cmpi.w #SM_KPRS,d0 \| is this the key pressure source ?
395	bne srctyp4 \| jump if not (must be an analog input)
396
397	move.w FH_TRG(a1),d0 \| get the trigger number
398	add.w d0,d0 \| ... as a word index
399	lea prstab,a0 \| ... into prstab[]
400	move.w 0(a0,d0.W),d5 \| get the pressure from prstab[trg]
401	bra applym \| go apply the multiplier
402
403	.page
404	\| ------------------------------------------------------------------------------
405	\| all other sources come out of the valents[] array
406	\| ------------------------------------------------------------------------------
407	srctyp4: lea vce2grp,a0 \| point at vce2grp[]
408	move.w _curpf_f,d5 \| get voice number in d5
409	lsr.w #3,d5 \| ...
410	andi.w #0x001E,d5 \| ... as a word index
411	move.w 0(a0,d5.W),d5 \| get the group number
412	subq.w #1,d5 \| ...
413	lsl.w #4,d5 \| shift it left a nybble
414	or.w d5,d0 \| OR it into the source number
415	add.w d0,d0 \| make source number a valents[] index
416	move.w d0,d5 \| ... (fast multiply by VALLEN = 10
417	lsl.w #2,d0 \| ... via shift and add)
418	add.w d5,d0 \| ...
419	lea valents,a0 \| get base of valents[]
420	move.w VT_VAL(a0,d0.W),d5 \| get value
421
422	\| ------------------------------------------------------------------------------
423	\| apply the multiplier to the source, and add it to the function value
424	\| ------------------------------------------------------------------------------
425	applym: muls PT_VMLT(a2,d2.W),d5 \| apply the multiplier
426	asr.l #7,d5 \| scale the result
427	asr.l #8,d5 \| ...
428	ext.l d3 \| add the function value
429	add.l d3,d5 \| ...
430	cmpi.l #VALMAX,d5 \| check for overflow
431	ble srcmlt1 \| jump if no overflow
432
433	move.l #VALMAX,d5 \| limit at VALMAX
434	bra srcmlt2 \| ...
435
436	srcmlt1: cmpi.l #VALMIN,d5 \| check for underflow
437	bge srcmlt2 \| jump if no underflow
438
439	move.l #VALMIN,d5 \| limit at VALMIN
440
441	srcmlt2: move.w d5,d3 \| setup value for output to FPU
442
443	.page
444	\| ------------------------------------------------------------------------------
445	\| adjust the value according to the function type
446	\| ------------------------------------------------------------------------------
447	nosrc: move.w d1,d0 \| get function type
448	andi.w #0x01E0,d0 \| ...
449
450	\| ------------------------------------------------------------------------------
451	\| level or location
452	\| ------------------------------------------------------------------------------
453	cmpi.w #P_LEVEL,d0 \| see if it's the level
454	beq outsegl \| jump if so
455
456	cmpi.w #P_LOCN,d0 \| see if it's the location
457	bne outsegf \| jump if not
458
459	tst.w d3 \| check sign of value
460	bpl outsegc \| jump if positive
461
462	clr.w d3 \| force negative values to 0
463
464	outsegc: asr.w #5,d3 \| shift value to LS bits
465	sub.w #500,d3 \| subtract 5.00 from value
466	asl.w #6,d3 \| readjust to MS bits
467	bra outseg3 \| go output the value
468
469	outsegl: tst.w d3 \| check sign of value
470	bpl outsegm \| jump if positive
471
472	clr.w d3 \| limit negative values at 0
473
474	outsegm: asr.w #5,d3 \| shift value to LS bits
475	sub.w #500,d3 \| subtract 5.00 from value
476	asl.w #6,d3 \| readjust to MS bits
477	bra outseg3 \| go output the value
478
479	.page
480	\| ------------------------------------------------------------------------------
481	\| filter
482	\| ------------------------------------------------------------------------------
483	outsegf: cmpi.w #P_FILTER,d0 \| see if it's the filter
484	bne outsegp \| jump if not
485
486	ext.l d3 \| make function value a long
487	asr.l #1,d3 \| multiply function value by .75
488	move.l d3,d0 \| ... (fast multiply by .75
489	asr.l #1,d0 \| ... via shift and add)
490	add.l d0,d3 \| ...
491	move.w (a1),d0 \| add pitch
492	ext.l d0 \| ...
493	add.l d0,d3 \| ...
494	cmpi.l #VALMAX,d3 \| see if it's within limits
495	ble outsega \| ...
496
497	move.w #VALMAX,d3 \| limit at VALMAX
498	bra outseg3 \| ...
499
500	outsega: cmpi.l #VALMIN,d3 \| ...
501	bge outseg3 \| ...
502
503	move.w #VALMIN,d3 \| limit at VALMIN
504	bra outseg3 \| ...
505
506	.page
507	\| ------------------------------------------------------------------------------
508	\| freq 1..4
509	\| ------------------------------------------------------------------------------
510	outsegp: cmpi.w #P_FREQ1,d0 \| see if it's freq1
511	beq outseg0 \| go process freq1
512
513	outsegq: cmpi.w #P_FREQ2,d0 \| see if it's freq2
514	beq outseg0 \| process it if so
515
516	cmpi.w #P_FREQ3,d0 \| see if it's freq3
517	beq outseg0 \| process it if so
518
519	cmpi.w #P_FREQ4,d0 \| see if it's freq4
520	bne outseg3 \| jump if not
521
522	outseg0: ext.l d3 \| scale the point value to cents offset
523	asr.l #5,d3 \| ...
524	sub.l #500,d3 \| ... value - 500
525	asl.l #LSPCH,d3 \| mult. by 2 and scale for 1/2 cent lsb
526	move.w (a1),d0 \| add pitch from function header
527	ext.l d0 \| ...
528	add.l d0,d3 \| ...
529	cmp.l #PCHMAX,d3 \| see if result is valid
530	ble outseg3 \| jump if within pitch limits
531
532	move.l #PCHMAX,d3 \| limit at maximum pitch
533
534	\| ------------------------------------------------------------------------------
535	\| send the value to the FPU
536	\| ------------------------------------------------------------------------------
537	outseg3: move.b FH_TMD(a1),d0 \| get hardware bits from function header
538	eor.w #VAL_BITS,d0 \| toggle new value select bits
539	move.b d0,FH_TMD(a1) \| store updated word
540	btst.l #VSUBNBIT,d0 \| check which value address to use
541	beq outseg1
542
543	move.w d3,F_VAL01(a3,d1.W) \| send value to FPU
544	bra outseg2
545
546	outseg1: move.w d3,F_VAL10(a3,d1.W) \| send value to FPU
547
548	outseg2: andi.w #MSK_CTL,d0 \| mask off software bits
549	ori.w #UPD_BIT+INT_BIT,d0 \| set the update & !lastseg bits
550	move.w d0,F_CTL(a3,d1.W) \| send control word to FPU
551	bra pfnext \| done -- exit
552
553	.page
554
555	\| ------------------------------------------------------------------------------
556	\| act2 -- AC_ENBL -- stop if key is up
557	\| ---- ----------------------------
558	act2: move.w _curpf_f,d0 \| get voice as a word index
559	lsr.w #3,d0 \| ...
560	andi.w #0x001E,d0 \| ...
561	lea vce2trg,a0 \| check to see if voice is free
562	move.w 0(a0,d0.W),d0 \| ...
563	cmpi.w #-1,d0 \| ...
564	beq stopfn \| if so, stop the function
565
566	btst #15,d0 \| see if voice is held
567	bne act0 \| continue if so
568
569	btst #14,d0 \| ...
570	bne act0 \| ...
571
572	lea trgtab,a0 \| check trigger table entry
573	tst.b 0(a0,d0.W) \| ...
574	bne act0 \| if trigger is active, continue
575
576	bra stopfn \| if not, stop the function
577
578	\| ------------------------------------------------------------------------------
579	\| act3 -- AC_JUMP -- unconditional jump
580	\| ---- -----------------------------
581	act3: cmp.b FH_PIF(a1),d4 \| check jump point against limit
582	bcc stopfn \| stop function if jump point invalid
583
584	clr.w d2 \| get index of first point
585	move.b FH_PT1(a1),d2 \| ...
586	add.b d4,d2 \| add jump point
587	move.b d2,FH_CPT(a1) \| make it the current point
588	lsl.w #2,d2 \| develop new point index in d2
589	move.w d2,d0 \| ... (fast multiply by PT_LEN = 12
590	add.w d2,d2 \| ... via shift and add)
591	add.w d0,d2 \| ...
592	bra outseg \| output the segment
593
594	.page
595
596	\| ------------------------------------------------------------------------------
597	\| act4 -- AC_LOOP -- jump to point PT_PAR1 PT_PAR2 times
598	\| ---- ----------------------------------------------
599	act4: tst.b PT_PAR3(a2,d2.W) \| check counter
600	bne act4a \| jump if it's running
601
602	move.b PT_PAR2(a2,d2.W),d0 \| get parameter
603	subi.w #90,d0 \| put parameter in random range
604	bmi act4b \| treat as normal if < 90
605
606	movem.l d1-d2/a0-a2,-(a7) \| get ranged random number
607	move.w d0,-(a7) \| ...
608	jsr irand \| ...
609	tst.w (a7)+ \| ...
610	movem.l (a7)+,d1-d2/a0-a2 \| ...
611	move.b d0,PT_PAR3(a2,d2.w) \| set counter
612	beq act0 \| next segment if cntr set to 0
613
614	bra act3 \| else jump to the point
615
616	act4b: move.b PT_PAR2(a2,d2.W),PT_PAR3(a2,d2.W) \| set counter
617	beq act0 \| next segment if cntr set to 0
618
619	bra act3 \| else jump to the point
620
621	act4a: subq.b #1,PT_PAR3(a2,d2.W) \| decrement counter
622	beq act0 \| next segment if cntr ran out
623
624	bra act3 \| jump if it's still non-zero
625
626	\| ------------------------------------------------------------------------------
627	\| act5 -- AC_KYUP -- jump if key is up
628	\| ---- ----------------------------
629	act5: move.w _curpf_f,d0 \| get voice as a word index
630	lsr.w #3,d0 \| ...
631	andi.w #0x001E,d0 \| ...
632	lea vce2trg,a0 \| check to see if voice is free
633	move.w 0(a0,d0.W),d0 \| ...
634	cmpi.w #-1,d0 \| ...
635	beq act3 \| if so (inactive), do the jump
636
637	btst #15,d0 \| see if voice is held
638	bne act0 \| continue if so
639
640	btst #14,d0 \| ...
641	bne act0 \| ...
642
643	lea trgtab,a0 \| check trigger table entry
644	tst.b 0(a0,d0.W) \| see if the trigger is active
645	beq act3 \| if not, do the jump
646
647	bra act0 \| if so, do next segment
648
649	.page
650
651	\| ------------------------------------------------------------------------------
652	\| act6 -- AC_KYDN -- jump if key is down
653	\| ---- ------------------------------
654	act6: move.w _curpf_f,d0 \| get voice as a word index
655	lsr.w #3,d0 \| ...
656	andi.w #0x001E,d0 \| ...
657	lea vce2trg,a0 \| check to see if voice is free
658	move.w 0(a0,d0.W),d0 \| ...
659	cmpi.w #-1,d0 \| ...
660	beq act0 \| if so (inactive), continue
661
662	btst #15,d0 \| see if voice is held
663	bne act3 \| do jump if so
664
665	btst #14,d0 \| ...
666	bne act3 \| ...
667
668	lea trgtab,a0 \| check trigger table entry
669	tst.b 0(a0,d0.W) \| see if the trigger is active
670	bne act3 \| if so, do the jump
671
672	bra act0 \| if not, do next segment
673
674	\| ------------------------------------------------------------------------------
675	act7: bra act0 \| AC_HERE: treat act7 as AC_NULL
676
677	.page
678
679	\| act1 -- AC_SUST -- pause if key is down (sustain)
680	\| ---- -----------------------------------------
681	act1: move.w _curpf_f,d0 \| get voice as a word index
682	lsr.w #3,d0 \| ...
683	andi.w #0x001E,d0 \| ...
684	lea vce2trg,a0 \| point at voice to trigger table
685	move.w 0(a0,d0.W),d0 \| get trigger table entry
686	cmpi.w #-1,d0 \| see if voice is free
687	beq act0 \| treat as no-op if so
688
689	btst #15,d0 \| see if voice is held by a pedal
690	bne act1a \| sustain if so
691
692	btst #14,d0 \| see if voice is sustained by a pedal
693	bne act1a \| sustain if so
694
695	lea trgtab,a0 \| point at trigger table
696	tst.b 0(a0,d0.W) \| check trigger status
697	beq act0 \| continue if not active
698
699	act1a: move.l pfqhdr,d3 \| see if any pflist entries remain
700	beq act0 \| no-op if not (shouldn't happen ...)
701
702	move.b FH_PT1(a1),d0 \| get first point number
703	add.b FH_PIF(a1),d0 \| add base to first point
704	subq.b #1,d0 \| make d0 last point number
705	cmp.b FH_CPT(a1),d0 \| check current point number
706	beq stopfn \| done if this is the last point
707
708	addq.b #1,FH_CPT(a1) \| update current point number
709	addi.w #PT_LEN,d2 \| update point index
710	movea.l d3,a0 \| acquire a new pflist entry
711	move.l (a0),pfqhdr \| ...
712	move.l pflist,(a0) \| ...
713	move.l a0,pflist \| ...
714	move.w FH_TRG(a1),PF_TRIG(a0) \| set trigger number in entry
715	move.w _curpf_f,PF_FUNC(a0) \| set v/p word in entry
716	movem.l d1-d2/d4/a1-a3,PF_D1(a0) \| set registers in entry
717	move.b FH_TMD(a1),d0 \| stop the function
718	andi.w #MSK_RNVB,d0 \| ...
719	move.w d0,d3 \| ...
720	add.w d3,d3 \| ...
721	andi.w #MSK_ONVB,d3 \| ...
722	or.w d3,d0 \| ...
723	move.w d0,F_CTL(a3,d1.W) \| ...
724	bra pfnext \| go do next list entry
725
726	.page
727	\| ------------------------------------------------------------------------------
728	.data
729	\| ------------------------------------------------------------------------------
730
731	\| actab -- action code dispatch table
732	\| ----- --------------------------
733	actab: .dc.l act0 \| 0 - AC_NULL: no action
734	.dc.l act1 \| 1 - AC_SUST: sustain
735	.dc.l act2 \| 2 - AC_ENBL: enable
736	.dc.l act3 \| 3 - AC_JUMP: unconditional jump
737	.dc.l act4 \| 4 - AC_LOOP: jump n times (loop)
738	.dc.l act5 \| 5 - AC_KYUP: jump if key up (enable jump)
739	.dc.l act6 \| 6 - AC_KYDN: jump if key down (sustain jump)
740	.dc.l act7 \| 7 - AC_HERE: here on key up
741
742	\| ------------------------------------------------------------------------------
743	.bss
744	\| ------------------------------------------------------------------------------
745
746	\| ----------------- local variables --------------------------------------------
747
748	_curpf_f: .ds.w 1 \| interrupting voice & parameter from FPU
749
750	\| ----------------- debug variables --------------------------------------------
751
752	_curpf_t: .ds.w 1 \| current trigger
753
754	_curpf_l: .ds.l 1 \| current pflist entry
755
756	\| ------------------------------------------------------------------------------
757
758	.end

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