Mod Player/4

 BBS: Inland Empire Archive
Date: 11-30-92 (21:16)             Number: 376
From: RICH GELDREICH               Refer#: NONE
  To: ALL                           Recvd: NO  
Subj: Mod Player/4                   Conf: (2) Quik_Bas
'<<Part 4 Starts Here>>
'Initialize the assembly buffer player.
SetBuffers VARSEG(SampleBuffer(0)), VARPTR(SampleBuffer(0)), _
           VARPTR(SampleBuffer(512)), IntsPerClick * 2

'Set int 8 to our asm routine = &H2508:CPU.ds = GetCS:CPU.dx = GetOF
CALL interruptx(&H21, CPU, CPU)

'Reprogram the 8255's timer to the specified sample rate.
SetInt8Rate &H1234DE \ IntRate

'Turn speaker on, and play the MOD.

    'Wait for sync signal from the assembly buffer player...
    DO: LOOP UNTIL CheckDoneFlag

    'Mix another buffer.
    GOSUB DoMix

    IF A$<>"" THEN  'Process any keystrokes.
        CASE 49 TO 52
             ChannelOn(K-49) = NOT ChannelOn(K-49)
        CASE 27
             Exit do
        CASE &H4b 'Left
            IF T.Pos<0 THEN T.Pos=T.Length-1
            GOSUB StartNewPattern
        CASE &H4d 'Right
            IF T.Pos=>T.Length THEN T.Pos=0
            GOSUB StartNewPattern
        END SELECT

'Turn off speaker.
'Set int 8 rate to normal (18.2 hz)
SetInt8Rate 0

'restore old int 8 handler = &H2508:CPU.ds = Old8.Segment:CPU.dx = Old8.Offset
CALL interruptx(&H21, CPU, CPU)

'Processes 1 line(4 channels) of a pattern.
    DEF SEG = PatternSegment

    FOR A = 0 TO 3
        C = PEEK(T.Offset): T.Offset = T.Offset + 1

        IF C <> 0 THEN  'Process a new sample, if any.
            C = C - 1
            C.Segment(A)        = S.Segment(C)
            C.Volume(A)         = S.Volume(C)
            C.RepStart(A)       = S.RepStart(C)
            C.RepLength(A)      = S.RepLength(C)
            C.Length(A)         = S.Length(C)
            C.LoopEnd(A)        = C.Length(A)
        END IF

        C = PEEK(T.Offset) * 256 + PEEK(T.Offset + 1)
        T.Offset = T.Offset + 2
        IF C <> 0 THEN  'Process a new period, if any.
            IF PEEK(T.Offset) <> 3 THEN
                C.Period(A)     = C
                C.HighStep(A)   = PeriodHigh(C) 'Lookup the step rate of
                C.LowStep(A)    = PeriodLow(C)  'the new period.
                C.Offset(A)     = 0
                C.LoopEnd(A)    = C.Length(A)
                C.Remainder(A)  = -256
                C.InactiveFlag(A) = False
            END IF
        END IF

        C.Command(A) = 0
        M = PEEK(T.Offset)
        IF M<>0 THEN    'Process a command, if any.
            o = PEEK(T.Offset + 1)
            SELECT CASE M
            CASE 12             'Volume
                C.Volume(A) = o
            CASE 15             'Tempo
                T.Tempo = o
'<<-Continued On Next Message->>

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