Interrupts in ACTION#

General Information

Author: David Plotkin
Language: ACTION!
Compiler/Interpreter: ACTION
Published: ANALOG July 1984

PDF: Interrupts in ACTION/interruptinaction.PDF

MODULE; VBI DEMO FOR ANTIC
DEFINE RTI="$40",
       PHA="$48",
       PLA="$68",
       TXA="$8A",
       TAX="$AA",
       TYA="$98",
       TAY="$A8",
       JMP="$4C",
       XITVBV="$E462",

SAVETEMPS="[$A2 $07 $B5 $C0 $48 $B5
    $A8 $48 $B5 $A0 $48 $B5 $80 $48  
    $CA $10 $F2 $A5 $D3 $48]",
GETTEMPS="[$68 $85 $D3 $A2 $00 $68
    $95 $80 $68 $95 $A0 $68 $95 $A8
    $68 $95 $C0 $E8 $E0 $08 $D0 $F0]"
CARD SDLST=560,VDSLST=512,
               VVBLKD=$224
BYTE NMIEN=$D40E,COLBK=$D01A,
     WSYNC=$D40A,COUNT=[0]
BYTE ARRAY DLIST
BYTE ARRAY CLRS(0)=[64 66 68 70 72 74
     72 70 68 66  64  66  68  70  72
     74  72  70  68  66  64  66  68
     70 72 74 76 ]

PROC DLINT(); a DLI written in ACTION!
    BYTE DUM
    [PHA TXA PHA TYA PHA]
    IF COUNT=26 THEN DUM=0
    ELSE DUM=CLRS(COUNT) FI
    WSYNC=1
    COLBK=DUM
    COUNT=COUNT+1
    IF COUNT=27
    THEN COUNT=0
    FI
    [PLA TAY PLA TAX PLA RTI]

PROC INIT7()
    GRAPHICS(7)
    SETCOLOR(0,2,10)
    SETCOLOR(1,5,12)
    SETCOLOR(2,0,0)
RETURN

PROC DLSETUP(); custom Display List
    BYTE I
    INIT7()
    NMIEN=$40
    DLIST=SDLST  
    VDSLST=DLINT
    FOR I=30 TO 40
    DO DLIST(I)=141 OD
    FOR I=42 TO 54 STEP 2
    DO DLIST(I)=141 OD
    FOR I=57 TO 72 STEP 3
    DO DLIST(I)=141 OD
    FOR I=76 TO 84 STEP 4
    DO DLIST(I)=141 OD
    NMIEN=$C0
RETURN

PROC ROTATE(); the VBI routine
    BYTE HOLD,CTR,CNTR
    SAVETEMPS; save the temp registers
    HOLD=CLRS(26); save the last element
    FOR CTR=0 TO 25; the loop
    DO CNTR=25-CTR; to count backwards, Action! has no STEP-1 statement
    CLRS(CNTR+1)=CLRS(CNTR) OD; rotate
    CLRS(0)=HOLD; put the last element into the first
    GETTEMPS; get the temp registers
    [JMP XITVBV]; exit the VBI

PROC VBINST(); install the VBI
    NMIEN=0; turn off the interrupts
    VVBLKD=ROTATE; vector to PROC ROTATE
    NMIEN=$40; turn the interrupts back on
RETURN

PROC DJD(); the driver routine, named for a famous computer genius
    BYTE CRSINH=752
    VBINST(); install the VBI
    DLSETUP(); set up the Display List
    CRSINH=1
    PRINTE()
    PRINTE("Áîôéã Interrupts in ACTION!")
    PRINT("           by DAVID PLOTKIN")
    DO OD; an endless loop...
RETURN