ORG $3f00 ; ***************************************************************************** ; * The Music Studio Player Engine ; * ; * Based on code written by Sasa Pusica for the utility, The Music Studio. ; * Modified by Chris Cowley ; * ; * Produced by Beepola v1.06.01 ; * ; * Z80 to 6809 conversion by John Kowalski (Sock Master) ; * ; * Original Z80 to 6809 conversion idea and debugging by Simon Jonassen ; * ; * 6809 code changes and optimization by Steve Evans (Zephyr) ; * http://archive.worldofdragon.org/ ; * ; * Sliding VU by Simon Jonassen ; * ; ****************************************************************************** start jsr >check_dos pshs dp lda #$3f ; Set DP = $3F tfr a,dp setdp $3f jsr >initvu ldy #$ff20 ldd #PATTERNDATA ; Get start address of pattern data addd MUSICDATA ; Add loop start point to the pattern data start address tfr d,x ; Transfer pattern data loop start address to the X register ldd #PATTERNDATA ; Get start address of pattern data addd MUSICDATA+2 ; Add song length to the pattern data loop start address std audio_on ; Select DAC as sound source and enable audio ; ******************************************************************************************************** ; * NEXT_PATTERN ; * ; * Select the next pattern in sequence (and handle looping if we've reached PATTERN_LOOP_END ; * Execution falls through to PLAYNOTE to play the first note from our next pattern ; ******************************************************************************************************** nextpat lda [,x] ; X = Pattern data pointer sta audio_off ; Disable audio and return to basic continue sta $20 then this is not a drum effect, skip the INC D inc $20 then this is not a drum effect, skip the INC D inc $0088 bsr cls rts vu pshs d,x ; CHANNEL 1 lda #133 ldx #$4a0 ldb