what

$eject
main:   retad   main        ;main loop
    tst kyflag
    jnz ertst       ;test timeout error
    call    keytst
    jnz main0       ;no
    lda clock
    adi 100
    jnz nzero
    inr a
nzero:  sta kyflag      ;set 40ms error delay
main0:  di
    tst bbsyf
    jnz sendnw      ;only play control
    tst commf       ;valid command?
    jm  comexe      ;execute new command
    call    keytst      ;test "open" key
    jz  keyon
    call    sstat       ;no valid status
sendnw: ei
    lhld    searr       ;search & play routines
    pchl            ;branch

ertst:  lda clock
    lxi h,kyflag
    cmp m
    jnz main0
    mvi m,0     ;timeout, reset timer
    di
    jmp keyon

sstat:  tst stval       ;test status valid
    rnz
    tst playd
    rnz         ;play disabled
    fifost  sfifo       ;test status fifo
    rz          ;empty
    rdff    sfifo       ;read next status
    mov c,a
    ani 3
    sta modeb
    mov a,c
    ani daterr
    ori dready      ;set data ready
    sta status      ;write status
    mvi a,1
    sta stval       ;set status valid flag
    ret

    mark
keytst: lda inerr
    ani key
    ret
$eject