00100		TITLE	BUFFER;  DOROTHY BENDER ****** GARPLY *******
00200	
00300	;  ROUTINE TO READ THE OUTPUT FROM THE MUSIC
00400	;  PROGRAM AND CALL THE D-A CONVERTER TO PLAY.
00500	;  
00600	;  THE NAME OF THE FILE TO BE INPUTTED IS 'MUSIC',
00700	;  THE FIRST RECORD OF WHICH CONTAINS THE
00800	;  NUMBER OF WORDS OF DATA IN THE ENTIRE DISK FILE.
00900	
01000	A   ←   1     ;WORK
01100	B   ←   2     ;WORK
01200	RET ←   3     ;RETURN ACCUMULATOR
01300	BUFSIZ ←=20224   
01400	↓DSKCHN ←1             ;DISK CHANNEL FOR INPUT
01500	↓ADCHN  ←2             ;D-A CHANNEL FOR OUTPUT
01600	
01700		OPDEF	READCH [51B8]
01800	        OPDEF   MESSAGE[51B8!3B12]
01900	
02000	BEG:	CALLI	0,0         ;RESET I/O DEVICES
02100	 	OPEN 	DSKCHN,[17  ;MODE
02200			'DSK   '    ;DEVICE NAME
02300	 		0]          ;NO BUFFER HEADERS
02400		HALT	BEG         ;RESTART IF DEVICE IS UNAVAILABLE
02500	
02600	 	SETZM	FILBLK+3    ;FOR RESTART
02700	 	SETZM	FILBL2+3    ;FOR RESTART
02800	LX:	MESSAGE [ASCIZ/
02900	  TYPE `P' TO PLAY FROM DISK, `C' TO COPY TAPE TO DISK.
03000	/]
03100		readch a
03200		cain a,"C"
03300		jrst start
03400		caie a,"P"
03500		jrst lx
03600		skipe filblk+3	;is this first time through ?
03700		jrst pla2	;No. Parameters already set up.
03800		;FIND OUT NUMBER OF CHANNELS AND
03900		;THE SPEED.
04000	
04100		MESSAGE	[ASCIZ/HOW MANY CHANNELS?/]
04200		READCH	A
04300		SUBI	A,"0"+1		;CONVERT TO BINR AND ADD 1
04400		DPB	A,[POINT 2,OUTBIT,26]
04500	
04600		MESSAGE [ASCIZ/WHAT IS THE SPEED?/]
04700		READCH  A
04800		SUBI	A,"0"
04900		DPB	A,[POINT 3,OUTBIT,32]
05000	
05100	PLA2:	SETZM FILBLK+3
05200		SETZM FILBL2+3
05300		LOOKUP	DSKCHN,FILBLK
05400		SKIPA			;CAN'T FIND MUSIC.MUS
05500		JRST XOPEN		;FOUND IT
05600		LOOKUP  DSKCHN,FILBL2	;TRY FOR MUSAA.DMD
05700	
05800		JRST	[MESSAGE[ASCIZ/
05900			*** MUSIC FILE NOT FOUND/]
06000			CALLI  12]
06100	        ;EXIT IF FILE IS MISSING
06200		MOVE A,FILBL2+3	;GET LENGTH OF MUSAA.DMD
06300		MOVEM A,FILBLK+3;PUT IT IN RIGHT PLACE
06400	
06402	XOPEN:	MOVSI	'XGP'	;DOWN TO XGPOK FOR XGP CONFLICT.
06412		DEVUSE	0,	
06422		HLRZ 	0,0
06432		CAIN	400000
06442		JRST	XGPOK
06452		INIT	16,17
06462		SIXBIT	.XGP.
06472		0
06482		JRA	16,2(16)
06500	XGPOK:	OPEN	ADCHN,[117 	;MODE
06600	         	'AD    '        ;DEVICE NAME
06700	 		0]              ;NO BUFFER HEADERS
06800	
06900	  	JRST	[MESSAGE[ASCIZ/
07000			***D-A NOT AVAILABLE/]
07100			CALLI  12]
07200		;EXIT IF D-A IS UNAVAILABLE
07300	
07400	SPWAR:	SPCWAR 17,[CALLI]
07500		MESSAGE [ASCIZ/ GO? /]
07600		READCH A
07700	
07800	
07900	LNTH:	movs a,filblk+3		;get length of file.
08000		movnm a,nwd
08100	
08200	;	-----------------------------------------
08300	
08400		;BEGIN MAIN BODY OF PROGRAM
08500	
08600	LOOP:	JSP	RET,SUB		;ROUTINE TO READ AND WRITE
08700		BUF1-1 			;USE BUF1 FOR THE I/O
08800		JUMPLE	B,OUT    	;DONE
08900		
09000		JSP	RET,SUB		;CALL IT AGAIN
09100		BUF2-1			;USE BUF2 FOR THE I/O
09200		JUMPG	B,LOOP		;GO BACK FOR MORE IF B>0
09300	
09400	OUT:	close dskchn,		;END OF PROGRAM.
09500		releas adchn,
09550		RELEASE 16,
09600		SPCWAR 0,'SSW'
09700		jrst lx
09800	
09900		;SUBROUTINE TO SET UP IOWD AND READ AND WRITE.
10000		;  1(RET) WILL BE THE RETURN
10100		;  0(RET) WILL BE THE ADDRESS OF THE BUFFER TO BE
10200		;         PUT IN THE RIGHT HALF OF THE IOWD.
10300		;  A      WILL BE A WORK REGISTER
10400	    	;  B      WILL BE TESTED ON THE OUTSIDE.
10500	
10600	SUB:	MOVNI	A,BUFSIZ	;PICK UP AND COMPLEMENT BUFSIZ
10700		ADDB	A,NWD		;A←NWD-BUFSIZ
10800					;NWD←NWD-BUFSIZ
10900		MOVE	B,A		;SAVE B TO BE TESTED FOR LAST
11000					;TIME.
11100		JUMPL	A,LAST		;SET UP FOR LAST TIME.
11200		MOVEI	A,0		
11300	
11400		;THE IOWD LOOKS LIKE:
11500		;  [-BUFSIZ / BUFI-1]
11600	
11700	LAST:	ADDI	A,BUFSIZ
11800		MOVNS	A		;COMPLEMENT A
11900		HRL	A,0(RET)	;PICK UP BUFI AND MOVE IT
12000					;TO THE LEFT SIDE OF A.
12100		MOVSM	A,INLIST	;SWAP A AND MOVE IT.
12200		MOVSM	A,OUTWC		;SAME FOR OUTPUT.
12300		INPUT	DSKCHN,INLIST	;READ A RECORD.
12400		OUTPUT	ADCHN,OUTWC	;WRITE THE RECORD.
12500		JRST	1(RET)		;RETURN
12600	
12700	;	-----------------------------------------
12800	
12900	; STORAGE:
13000	
13100	NWD:	0			;FOR NUMBER OF WORDS OF INPUT.
13200	↓BUF1:	BLOCK	BUFSIZ+1	;BUFFER 1
13300	BUF2:	BLOCK	BUFSIZ+1	;BUFFER 2
13400	
13500	FILBLK: 'MUSIC '		;FILENAME FOR INPUT
13600		'MUS   '			;EXTENSION
13700		0			;INFORMATION ON FILE
13800		0			;PROJECT PROG#
13900	
14000	FILBL2: 'MUSAA '		;FILENAME FOR INPUT, 2ND CHOICE
14100		'DMD   '			;EXTENSION
14200		0			;INFORMATION ON FILE
14300		0			;PROJECT PROG#
14400	
14500	CLIST:	IOWD	1,NWD		;FOR THE FIRST RECORD
14600		0
14700	
14800	INLIST:	0			;WILL CONTAIN AN IOWD
14900		0
15000	
15100	OUTWC:	0			;WILL CONTAIN AN IOWD FOR D-A
15200		3650			;MAGIC BITS FOR 136.
15300	OUTBIT: 4000			;BITS FOR D-A
15400		BLOCK	2
15500	
15600	begin magdsk
15700	
15800	A←1
15900	B←2
16000	D←3
16100	OLNG←=2432	;size of mag tape records. must be multiple of =128.
16200	
16300	ILNG←=2432
16400	ichn←adchn
16500	ochn←dskchn
16600	↑START:	CALLI 0
16700		INIT ICHN,3B28+17
16800		SIXBIT /MTA0/
16900		0
17000		HALT
17100		MTAPE ICHN,1	;REWIND THE TAPE
17200		JFCL
17300		INIT OCHN,17
17400		SIXBIT /DSK/
17500		0
17600		HALT
17700		ENTER OCHN,[SIXBIT /MUSIC/
17800	                    SIXBIT /MUS/
17900		            0
18000		            0]
18100		HALT
18200		loop:input ichn,olst
18300			statz ichn,20000
18400			jrst out	;end of tape.
18500			output ochn,olst
18600			jrst loop
18700	OLST:	IOWD OLNG,OBUF
18800		0
18900	obuf←← buf1
19000		bend magdsk
19100	
19200	end beg