MOJPRG  START   0

FIRST   LDS     #255
        LDA     G_SCRN
        STA     @CURSCR
        STA     @SVEC
LOOP    JSUB    DRAW
        ADD     #4
        STA     @SVEC
        J       LOOP

HALT    J       HALT  

DRAW    JSUB    PUSH
        RMO     T, A
        JSUB    PUSH
        RMO     S, A
        JSUB    PUSH   

        LDA     #0      .COUNTER      
        LDT     @OFFSET
STRT   COMP    @LEN
        JEQ     END

        JSUB    PUSH
        LDA     SVEC
        ADD     @OFFSET
        STA     ADDR
        LDA     @ADDR
        STA     @BASEY

        CLEAR A
        
LOOP1   COMP    FOUR
        JEQ     LEND
        LDS     @BASE
        MUL     #64
        ADDR    A, S
        DIV     #64
        STS     @BASEY
        JSUB    PUSH
        CLEAR   A

LOOP2   COMP    FOUR
        JEQ     LEND2
        LDS     @BASEY
        ADDR    A, S
        STS     @CUR

        LDS     #255
        STS     @CUR

        ADD     #1
        J       LOOP2 

LEND2     JSUB    POP
        ADD     #1
        J       LOOP1      

LEND    JSUB    POP
        ADD     #1
        JSUB    PUSH
        LDA     #3
        ADDR    A, T
        JSUB    POP
        J       STRT

END     JSUB    POP
        RMO     A, T
        JSUB    POP
        RMO     A, S
        JSUB    POP
        RSUB
        

PUSH    STA     @S_PTR
        LDA     S_PTR
        ADD     #3
        STA     S_PTR
        RSUB

POP     LDA     S_PTR
        SUB     #3
        STA     S_PTR
        LDA     @S_PTR
        RSUB

FOUR    WORD    X'000004'
ADDR    WORD    X'000000'
CUR     WORD    X'000000'
BASE    WORD    X'000000'
BASEY   WORD    X'000000'
LEN     WORD    X'000000'
G_SCRN  WORD    X'00A000'
CURSCR  WORD    X'000000'
KEY_IN  WORD    X'00C000'
S_PTR   WORD    X'000100'
SVEC    WORD    X'001000'
SVECMV  WORD    X'003000'
OFFSET  WORD    X'000000'

        END FIRST