;TechPop        Wes Philp›;               160 Sand Pine Road›;               Indialantic, FL 32903›;›DEFINE END="$FE", ;end of preset›       T="$FD",   ;timbre›       W="$FC",   ;wait›       M="$FB",   ;metronome›       EOL="$FF", ;end-of-list›       A="$A",B="$B",C="$C",D="$D",›       E="$E",F="$F",›       QUIET="0 0 0"›CARD ARRAY PRESETS(1)=[›INCLUDE "PRESETS"›EOL]›BYTE ARRAY TIMBRES(1)=[›INCLUDE "TIMBRES"›EOL]›;›; TRAP -------------------------------›BYTE BRKKEY=$11›PROC TRAP(BYTE N)›;stop on BREAK or any OS error›BRKKEY=0›RETURN›;›; ALERT ------------------------------›PROC ALERT(BYTE ARRAY STRING)›PRINTF("%E%S%E",STRING)›RETURN›;›; BUILD_DLI --------------------------›MODULE›CARD VDLI_OLD=[0],›     CLOCK=[0];counts at 4*frame rate›PROC BUILD_DLI()›;delay list interrupt servicer›;increments 16-bit CLOCK›;›BYTE ARRAY DLISERVE(1)=[›$48            ;PHA›$18            ;CLC›$A9 $01        ;LDA 1›$6D]           ;ADC LSB›BYTE POINTER D1=CLOCK›BYTE ARRAY D2(1)=[›$8D]           ;STA LSB›BYTE POINTER D3=CLOCK›BYTE ARRAY D4(1)=[›$90 $03        ;BCC 3›$EE]           ;INC MSB›BYTE POINTER D5=CLOCK+1›BYTE ARRAY D6(1)=[›$68            ;PLA›$40]           ;RTI›;›BYTE ARRAY MOD_LIST(1)=[›0 8 16 24]›BYTE I,›     NMIEN=$D40E›CARD VDLI=$200›BYTE POINTER BP›CARD POINTER SDLST=560›;›;install the DLI service routine›VDLI_OLD=VDLI›VDLI=DLISERVE›NMIEN=$C0 ;DLI and VBI›;modify the display list›FOR I=0 TO 3 DO›  BP=2+MOD_LIST(I)+SDLST^›  IF MOD_LIST(I)>=2 THEN›    BP==+2›  FI›  BP^==%$80›OD  ›BP=SDLST^›RETURN›;               ›; UNBUILD_DLI ------------------------›PROC UNBUILD_DLI()›BYTE NMIEN=$D40E›CARD VDLI=$200     ›NMIEN=$40 ;VBI only›VDLI=VDLI_OLD›GRAPHICS(0)›RETURN›;›; KBD --------------------------------›BYTE FUNC KBD(BYTE KCHAN,SCHAN)›;KCHAN=K: channel #›;SCHAN=S: channel #›;RETURN:›;  - operator-entered preset # (0-9)›;  - $FF no entry›;  - $FE BREAK›;  - $FD invalid input›;  - $FC >›;  - $FB <›BYTE CH=$02FC, ;keyboard character›     N,›     CR=[155]›IF BRKKEY=0 THEN›  ;BREAK key›  N=$FE›  BRKKEY=$FF›ELSEIF CH=$FF THEN›  ;no entry›  N=$FF›ELSE›  ;read the character›  N=GETD(KCHAN)›  IF BRKKEY=0 THEN›    N=$FE›    BRKKEY=$FF›  ELSEIF N='> THEN›    PUTD(SCHAN,N)›    N=$FC›  ELSEIF N='< THEN›    PUTD(SCHAN,N)›    N=$FB›  ELSEIF N>= '0 AND N<='9 THEN›    PUTD(SCHAN,N)›    PUTD(SCHAN,CR)›    N==-'0›  ELSEIF N=CR THEN ›    N=$FF ;ignore RETURN›  ELSE›    N=$FD ;invalid input›  FI›FI›RETURN(N)›;›; FIND_PRESET ------------------------›CARD FUNC FIND_PRESET(BYTE N)›;N=preset # (0,1 ...)›;RETURN:›;    - preset data address›;    - $FFFF if not found›BYTE I,›     PV›CARD POINTER P›P=PRESETS›I=0›DO›  PV=P^ ;LSB only›  IF I=N AND PV#EOL THEN›    ;done›    RETURN(P)›  ELSEIF PV=EOL THEN›    ;e.d-of-string found›    RETURN($FFFF)›  ELSEIF PV=END THEN›    I==+1›  FI›  P==+2›OD›;›; PREP_TIMBRE ------------------------›BYTE FUNC PREP_TIMBRE()›;RETURN: number of timbres defined›BYTE NT,›     I,›     DIST,›     L›BYTE POINTER BP›BP=TIMBRES›FOR NT=0 TO 254 DO›  DIST=BP^›  BP==+2›  L=BP^›  BP==+1›  IF DIST=EOL THEN›    NT==RSH 1›    RETURN(NT)›  ELSEIF L>0 THEN›    ;fix shapes by ORing distortion›    DIST==LSH 4›    FOR I=1 TO L DO›      BP^==%DIST›      BP==+1›    OD›  FI›OD›RETURN(0) ;error return›;›; INIT_TIMBRE ------------------------›PROC INIT_TIMBRE(BYTE N,V,›                 CARD ARRAY ADDR)›;N=timbre # (0,1 ...)›;V=voice (0 or 1)›;ADDR=addresses of 4 shape strings›;›BYTE I,J,›     L,›     CHAN›BYTE POINTER BP,›             AUDF›BP=TIMBRES›IF N#0 THEN›  ;skip over 2*N timbre arrays›  J=N+N›  FOR I=1 TO J DO›    BP==+2›    L=BP^›    BP==+L+1›  OD›FI›;›FOR I=0 TO 1 DO›  CHAN=V+V+I ;Atari voice # (0-3)›  BP==+1›  AUDF=CHAN+CHAN ;set AUDF›  AUDF==+$D200›  AUDF^=BP^›  BP==+1›  ADDR(CHAN)=BP ;timbre string address›  L=BP^         ;timbre string length›  BP==+L+1›OD›RETURN›;›; MODULATE ---------------------------›PROC MODULATE(CARD ARRAY ADDR,›              BYTE ARRAY OFFSET)›;ADDR=addresses of 4 shape strings›;OFFSET=clock offset for voices 0 & 1›BYTE V,›     IDX,›     LSB,›     I,J,›     L,›     CHAN›BYTE POINTER BP›BYTE ARRAY AUDC(1)=$D201›CHAN=0 ;0-3›FOR V=0 TO 1 DO›  ;loop over the two voices›  LSB=CLOCK ;compute the shape index›  IDX=LSB-OFFSET(V)›  IF IDX>127 THEN›    IDX=127›    OFFSET(V)=LSB+127›  FI›  FOR I=0 TO 1 DO›    ;loop over two channels per voice›    BP=ADDR(CHAN);timbre string addr›    L=BP^        ;timbre string length›    IF L>0 THEN›      IF IDX<L THEN ;J=MIN(IDX+1,L)›        J=IDX+1›      ELSE›        J=L›      FI›      BP==+J›      J=BP^›    ELSE›      J=0 ;no string - quiet›    FI›    AUDC(CHAN+CHAN)=J›    CHAN==+1›  OD›OD›RETURN›;›; QUANTUM ----------------------------›CARD FUNC QUANTUM(CARD R,N)›;R=metronome (quanta/sec)›;N=number of quanta to wait›;RETURN:›;  clock at end of wait=current+delta›;  where delta=4*60*N/rate›CARD DELTA›IF N>273 THEN›  N=273 ;overflow will occur›FI›DELTA=N*240›IF DELTA>32767 THEN›  DELTA==RSH 1›  R==RSH 1›FI›DELTA==/R›RETURN(DELTA+CLOCK)›;›; CONTINUE ---------------------------›BYTE FUNC CONTINUE(CARD ARRAY P,›                   INT SPEED,›                   BYTE N_TIMBRES)›;P=address of preset›;SPEED=operator modification to tempo›;N_TIMBRES=number of timbres defined›;RETURN:›;    0 - normal›;    1 - error›;›BYTE INIT=[1],›     COM,›     VOICE,›     I,›     STATUS›CARD R,›     N,›     NEXT›INT METRO›BYTE ARRAY AUD(1)=$D200,›           OFFSET(2),›           NULL(1)=[QUIET]›CARD ARRAY S_ADDR(4)›CARD POINTER OLD_P=[$FFFF]›;›IF INIT#0 THEN›  ;initialize›  INIT=0›  STATUS=0›  OLD_P=P›  VOICE=0›  ZERO(AUD,9)›  FOR N=0 TO 3 DO›    S_ADDR(N)=NULL›  OD›  CLOCK=0 ›  NEXT=CLOCK›FI›;›IF NEXT<=CLOCK THEN›  ;process a command from P array›  COM=OLD_P^›  OLD_P==+2›  IF COM=END THEN›    ;end of preset›    INIT=1›  ELSEIF COM=T THEN›    ;timbre›    VOICE==!1 ;flip between 0 and 1›    I=OLD_P^›    OLD_P==+2›    IF I<N_TIMBRES THEN›      INIT_TIMBRE(I,VOICE,S_ADDR)›      OFFSET(VOICE)=CLOCK ;LSB only›    ELSE›      STATUS=1 ;error›  FI›  ELSEIF COM=W THEN›    ;wait›    R=METRO+SPEED›    IF R>32767 THEN ;negative›      R=2›    FI›    N=OLD_P^›    OLD_P==+2›    NEXT=QUANTUM(R,N)›  ELSEIF COM=M THEN›    ;metronome›    METRO=OLD_P^›    OLD_P==+2›  ELSE›    STATUS=1 ;error›  FI›FI›IF STATUS=0 THEN›  ;continue playing›  MODULATE(S_ADDR,OFFSET)›ELSE›  ;error detected›  INIT=1›FI›RETURN(STATUS)›;›; TECHPOP ----------------------------›PROC TECHPOP()›BYTE CLICK=731,   ;XL keyclick switch›     RATE=730,    ;XL cursor rep rate›     CRSINH=$02F0,;cursor inhibit›     SKCTL=$D20F, ;serial port cntrl›     SSKCTL=$0232,; ... shadow›     KCHAN=[7],   ;kbd channel #›     N,›     N_TIMBRES›CARD OLD_ERROR,›     P=[$FFFF]›INT SPEED=[0]›;›GRAPHICS(0)›OLD_ERROR=ERROR›ERROR=TRAP›CLICK=$FF ;disable XL keyclick›SKCTL=3›SSKCTL=3›DEVICE=0›CLOSE(KCHAN)›OPEN(KCHAN,"K:",12,0)›BUILD_DLI()›CRSINH=$FF›PRINTF("%E         TechPop ")›PRINTF("Synthesizer       wp%E")›RATE=3 ;fast key auto-repeat›;›N_TIMBRES=PREP_TIMBRE();setup timbres›IF N_TIMBRES=0 THEN›  ALERT("invalid timbre format")›FI›;›DO›; N=KBD(KCHAN,SCHAN)›  N=KBD(KCHAN,0)›  IF N=$FF THEN›    ;no input›  ELSEIF N=$FE THEN›    ;BREAK key›    EXIT›  ELSEIF N=$FD THEN›    ALERT("?")›  ELSEIF N=$FC THEN›    ;speed up›    SPEED==+1›  ELSEIF N=$FB THEN›    ;slow down›    SPEED==-1›  ELSEIF N=$FF THEN›    ;no entry›  ELSE›    ;startup a new preset›    P=FIND_PRESET(N)›    SPEED=0›    IF P=$FFFF THEN›      ALERT("invalid preset")›    FI›  FI›  IF P#$FFFF THEN›    ;continue playing the preset›    N=CONTINUE(P,SPEED,N_TIMBRES)›    IF N#0 THEN›      ALERT("invalid preset")›      P=$FFFF›    FI›  FI›OD›BRKKEY=$FF›;›ERROR=OLD_ERROR›CLICK=0 ;reenable XL keyclick›UNBUILD_DLI()›SNDRST()›RETURN››