/       EXCITATION GENERATORS

/       EXCGEN USES TRIANGULAR ENVELOPE & SKIPS IF EVENT
/       DRONE1 GIVES FIXED PERIOD AND AMP = MAX MOD IN LAST PERIOD
/       DRONE2 GIVES FIXED PERIOD AND FIXED AMP.


*PART4

INIT,   0
        CLA
        DCA ENV
        DCA MOD
        TAD NUM
        CIA
        DCA COUNT
        TAD HEIGHT
        DCA HIGH
        DCA MDEC
        DCA DEC
        JMP I INIT

CHMOD,  0
        SPA
        CIA
        DCA MOD
        TAD MOD
        CIA CLL
        TAD ENV
        SZL SNA CLA
        JMP I CHMOD
        TAD MOD
        DCA ENV
        ISZ CHMOD
        JMP I CHMOD



EXCGEN, 0
        JMS CHMOD
        JMP I EXCGEN
        TAD ENV
        ASR
SHIFT,  0
        CMA             /AT LEAST 1 TO ENSURE DECAY
        DCA MDEC
        DCA DEC
        TAD ENV
        DCA HIGH
        ISZ EXCGEN      /SKIP IF EVENT
        JMP I EXCGEN


TRIEXC, 0       /LINEAR ENVELOPE DECAY
        JMS INIT
        TAD TRICON
        DCA SHIFT
        JMS I TRIEXC
TREXRA, 0
        JMS EXCGEN
        SKP
        ISZ TREXRA
        JMS TRIANG
        TAD HIGH
        JMP I TREXRA

PAREXC, 0       /PARABOLIC ENVELOPE DECAY
        JMS INIT
        TAD PARCON
        DCA SHIFT
        JMS I PAREXC
PREXRA, 0
        JMS EXCGEN
        SKP
        ISZ PREXRA
        JMS PARAB
        TAD HIGH
        JMP I PREXRA
        TAD .-1
        DCA EXCGEN
        JMP EXCGEN+1


TRIANG, 0
        TAD MDEC
        TAD ENV
        SPA
        CLA
        DCA ENV
        JMP I TRIANG


PARAB,  0
        TAD DEC
        TAD ENV
        SPA
        CLA
        DCA ENV
        TAD DEC
        TAD MDEC
        SMA
        CLA STL RAR
        DCA DEC
        JMP I PARAB




INDR1,  0
        JMS INIT
        JMS I INDR1

DRONE1, 0
        JMS CHMOD
        NOP
        ISZ COUNT
        JMP OUT
        TAD ENV
        DCA HIGH 
        DCA ENV
        TAD NUM
        CIA
        DCA COUNT
        ISZ DRONE1
OUT,    TAD HIGH
        JMP I DRONE1



INDR2,  0
        JMS INIT
        JMS I INDR2

DRONE2, 0
        CLA
        ISZ COUNT
        JMP OUT2
        TAD NUM
        CIA
        DCA COUNT
        ISZ DRONE2
OUT2,   TAD HIGH
        JMP I DRONE2


TRICON, 0
PARCON, 0
HEIGHT, 0
NUM,    0


MOD,    0
ENV,    0
DEC,    0
MDEC,   0
HIGH,   0
COUNT,  0
DECI,   0


        $$$$$$$$$$$$$$$$$$$$$$