kalama-sin/engine.tal

%k-RTN { JMP2r }

@k-tick
&run
  .kalama/tick LDZ #01 ADD DUP
  .kalama/speed LDZ EQU ,&play JCN
  .kalama/tick STZ
  k-RTN
  &play
  POP
  #ff .kalama/tick STZ
  .kalama/line LDZ #01 ADD STHk ( rst: line )
  #00 SWP #0003 MUL2 ;&lineaddr STA2 ( store line address offset )
  .kalama/songpos LDZ2 DUP2 ( songpos* songpos )
  ( don't play if song pos is ffff aka song is stopped or over )
  #ffff EQU2 ;&no-play JCN2 ( songpos* )
  #0005 ADD2 .kalama/module LDZ2 ADD2 ( songposinmod* )
  DUP2 LDA  ;k-get-pattern/run JSR2 ;&lineaddr LDA2 ADD2 #00 ;k-play-line/run JSR2
  DUP2 #0001 ADD2 LDA  ;k-get-pattern/run JSR2 ;&lineaddr LDA2 ADD2 #01 ;k-play-line/run JSR2  
  DUP2 #0002 ADD2 LDA  ;k-get-pattern/run JSR2 ;&lineaddr LDA2 ADD2 #02 ;k-play-line/run JSR2  
  #0003 ADD2 LDA  ;k-get-pattern/run JSR2 ;&lineaddr LDA2 ADD2 #03 ;k-play-line/run JSR2
  STHrk #0f EQU ,&next JCN 
  STHr .kalama/line STZ
  k-RTN
  &next
  POPr
  #ff .kalama/line STZ  .kalama/songpos LDZ2 #0004 ADD2 DUP2
  .kalama/module LDZ2 #0003 ADD2 LDA2 ( song length ) EQU2 ,&reset JCN
  .kalama/songpos STZ2
k-RTN
  &reset
  POP2
  .kalama/songloop LDZ #00 EQU ,&end JCN
  #0000 .kalama/songpos STZ2
k-RTN
  &end
  #ffff .kalama/songpos STZ2
k-RTN
  &no-play
  POP2 POP2 POPr
k-RTN
  &lineaddr $2

( initialises kalama with module data )
@k-init-module ( addr* -- )
&run  
  DUP2 .kalama/module STZ2 ( store module address )
  DUP2 LDA DUP
  #0f AND .kalama/speed STZ ( set speed )
  #80 AND .kalama/songloop STZ ( set song loop or not )
  #0001 ADD2 LDA ( stash pattern count byte )
  ;k-get-pattern JSR2 .kalama/instruments STZ2
  #ff .kalama/tick STZ
  #ff .kalama/line STZ
  #0000 .kalama/songpos STZ2
  
k-RTN

( gets the memory address of the given pattern in loaded module )
@k-get-pattern ( number -- addr* )
&run
  DUP #ff EQU ,&blank JCN
  #00 SWP #0030 MUL2
  .kalama/module LDZ2 #0003 ADD2 DUP2 LDA2 ADD2 #0002 ADD2 ADD2
  k-RTN
  &blank
  POP
  ;k-blank-pattern
k-RTN

( gets the memory address of the given instrument in loaded module )
@k-get-instrument ( number -- addr* )
&run
  STH ( store instrument number for later )
  .kalama/instruments LDZ2
  ( we are now at the size byte of instrument 00, the start of instrument memory )
  &loop
  STHrk #00 EQU ,&end JCN 
  STHr #01 SUB STH ( decrement counter )
  DUP2 LDA2 ( load length byte and convert to short )
  #0006 ADD2 ( jump over length short, vol, flags, ADSR )
  ADD2 ( jump to next instrument )
  ,&loop JMP
  
&end
POPr
k-RTN

@k-play-line ( *l channel -- )
&chan $1
&run
,&chan STR
DUP2 #0001 ADD2 LDA2 ,&chan LDR ;k-run-command/run JSR2
LDA DUP
  #00 EQU ,&rest JCN
  .kalama/loopflags LDZ ,&chan LDR #10 MUL #01 SWP SFT AND 
  #00 NEQ ,&noloop JCN
  #80 ORA
  &noloop
  .Audio0/pitch ,&chan LDR #10 MUL ADD DEO ( TODO effects, use loop bit )
  k-RTN
&rest
POP
k-RTN

@k-run-command ( c arg channel )
&chan $1
&run
;&chan STA
SWP ( get command )
DUP #01 EQU ;&vol JCN2 ( set volume )
DUP #02 EQU ;&instrument JCN2 ( set instrument )
DUP #03 EQU ;&attack JCN2 ( set attack time )
DUP #04 EQU ;&decay JCN2 ( set decay time )
DUP #05 EQU ;&sustain JCN2 ( set sustain time )
DUP #06 EQU ;&release JCN2 ( set sustain time )
DUP #07 EQU ;&speed JCN2 ( set speed )
POP2 k-RTN
&vol POP ;&chan LDA #10 MUL .Audio0/volume ADD DEO
k-RTN
&instrument POP ;&chan LDA ;k-load-instrument JSR2
k-RTN
&attack POP
  #0f AND #40 SFT ( shift new value into appropriate position )
  ;&chan LDA #10 MUL .Audio0/adsr ADD DEI ( load current value )
   #0f AND ( take only decay nibble ) 
   ADD ( add together new attack and old decay )
   ;&chan LDA #10 MUL .Audio0/adsr ADD DEO ( store )
k-RTN
&decay POP
  #0f AND
  ;&chan LDA #10 MUL .Audio0/adsr ADD DEI ( load current value )
   #f0 AND ( take only attack nibble ) 
   ADD ( add together new decay and old attack )
   ;&chan LDA #10 MUL .Audio0/adsr ADD DEO ( store )
k-RTN
&sustain POP
  #0f AND #40 SFT ( shift new value into appropriate position )
  ;&chan LDA #10 MUL .Audio0/adsr #01 ADD ADD DEI ( load current value )
   #0f AND ( take only decay nibble ) 
   ADD ( add together new attack and old decay )
   ;&chan LDA #10 MUL .Audio0/adsr #01 ADD ADD DEO ( store )
k-RTN
&release POP
  #0f AND
  ;&chan LDA #10 MUL .Audio0/adsr #01 ADD ADD DEI ( load current value )
   #f0 AND ( take only attack nibble ) 
   ADD ( add together new decay and old attack )
   ;&chan LDA #10 MUL .Audio0/adsr #01 ADD ADD DEO ( store )
k-RTN
&speed POP #0f AND .kalama/speed STZ #00 .kalama/tick STZ 
k-RTN

( loads instrument with number into specified audio channel, 0-indexed  )
@k-load-instrument ( number channel -- )
  &run
  #10 MUL STH ( stash channel * 0x10, offset for that channel's data relative to Audio0 )
  
  ;k-get-instrument JSR2 ( get instrument location )
  DUP2 LDA2 STHrk .Audio0/length ADD DEO2 ( copy ADSR value )
  #0002 ADD2 ( move to volume value )
  DUP2 LDA STHrk .Audio0/volume ADD DEO ( copy volume value )
  #0001 ADD2 DUP2 ( move to flags value )

  LDA #07 SFT ( MSB is set for looping sample, turn it into 0/1 ) 
  ( set or clear loop bit )
  #00 EQU ,&clear JCN
   #01 STHrk SFT .kalama/loopflags LDZ ORA .kalama/loopflags STZ ( set bit on )
   ,&end JMP
  &clear
    #01 STHrk SFT #ff EOR .kalama/loopflags LDZ AND .kalama/loopflags STZ ( set bit off )
  &end
  
  #0001 ADD2 LDA2k STHrk .Audio0/adsr ADD DEO2 ( copy ADSR value )

	#0002 ADD2 STHrk .Audio0/addr ADD DEO2
  
POPr
k-RTN

@k-blank-pattern $30