Tutorial 9
Using a program to turn off the calculator

Overview
    This program will turn off the calculator. WOW!

Programming
    The code is simple, it doesn't even include any ROM calls! Follow along now.

#define B_CALL(xxxx)
#define B_JUMP(xxxx)

        .org 9D95h

        DI ; disable interrupts
        LD A,001H                    ; Loading 0 to "a" register
        OUT (003H),A               ; turn off screen
        EI                               ;enabling interrupts
        RET

 
.end
END

New Commands Used
    DI - z80 Instruction that Disables Interrupts
    EI - z80 Instruction that Enables Interrupts

Conclusion
    What's to explain?

 

Tutorial 10

 

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