; ; MICROPLAY REV. A -- NEWTECH COMPUTER SYSTEMS, INC., JUNE 1977 ; ; FROM THE MODEL 6 MUSIC BOARD USERS MANUAL. PLAYS THE SCORE AT 100H ; THROUGH THE MODEL 6 AT PORT 24H. TIMED FOR AN 8080 AT 2 MHZ WITH ; NO WAIT STATES. ; ; THE SCORE IS THREE BYTES A NOTE: THE PITCH CONSTANT, THEN THE ; DURATION COUNT, LOW BYTE FIRST, WITH 1 ADDED TO THE HIGH BYTE. ; A ZERO PITCH ENDS THE SCORE, AND THE PROGRAM LOOPS AT HERE. ; ; THE PROGRAM WRITES THE NOTE INTO ITS OWN INSTRUCTIONS AT XFER1 ; TO XFER4, SO IT MUST RUN IN RAM. ; 0100 = SCORE EQU 0100H ;START OF THE SCORE 0024 = MODL6 EQU 24H ;MODEL 6 OUTPUT PORT 0000 = LNGTH EQU 0 ;PATCHED WITH THE DURATION 0000 = PITCH EQU 0 ;PATCHED WITH THE PITCH ; 0000 ORG 0 ; 0000 317F00 BEGIN: LXI SP,STACK 0003 210001 INIT: LXI H,SCORE 0006 226D00 SHLD PLACE 0009 2A6D00 NEXT: LHLD PLACE 000C 3E00 MVI A,0 000E BE CMP M 000F CA0F00 HERE: JZ HERE ;END OF SCORE: LOOP HERE 0012 7E MOV A,M ;PITCH 0013 324100 STA XFER2+1 0016 326000 STA XFER4+1 0019 23 INX H 001A 7E MOV A,M ;DURATION LSB 001B 323A00 STA XFER1+1 001E 325D00 STA XFER3+1 0021 23 INX H 0022 7E MOV A,M ;DURATION MSB 0023 323B00 STA XFER1+2 0026 325E00 STA XFER3+2 0029 23 INX H 002A 226D00 SHLD PLACE 002D CD3300 CALL PLAY 0030 C30900 JMP NEXT ; 0033 216500 PLAY: LXI H,TBL1 ;ENVELOPE POINTER 0036 1E08 MVI E,8 ;SEGMENT COUNT 0038 7E MOV A,M ;STARTING AMPLITUDE 0039 010000 XFER1: LXI B,LNGTH ;DURATION COUNT 003C 40 LOOP2: MOV B,B ;WASTE TIME 003D C34000 JMP XFER2 0040 1600 XFER2: MVI D,PITCH ;PITCH CONSTANT 0042 D324 OUT MODL6 ;OUTPUT HALF WAVE 0044 34 INR M ;WASTE MUCH TIME 0045 35 DCR M 0046 34 INR M 0047 35 DCR M 0048 34 INR M 0049 35 DCR M 004A 15 LOOP3: DCR D ;DELAY ACCORDING TO PITCH 004B C24A00 JNZ LOOP3 004E AE XRA M ;COMPLEMENT A. 004F 0D DCR C ;COUNT DOWN DURATION 0050 C23C00 JNZ LOOP2 0053 05 DCR B 0054 C24000 JNZ XFER2 0057 D324 OUT MODL6 0059 23 INX H ;NEXT SEGMENT 005A 1D DCR E 005B C8 RZ ;ALL SEGMENTS DONE 005C 010000 XFER3: LXI B,LNGTH 005F 1600 XFER4: MVI D,PITCH 0061 7E MOV A,M ;NEW AMPLITUDE 0062 C34A00 JMP LOOP3 ; 0065 9530D0FEFFTBL1: DB 095H,030H,0D0H,0FEH,0FFH,0FFH,030H,085H ;ENVELOPE 006D 0000 PLACE: DW 0 ;SCORE POINTER 007F = STACK EQU $+10H ; 006F END