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Macro VS Subroutine


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Hi, I have a problem.

I created a macro for update GRP1 X coordinate. Not the positioning, but only the value.

The code is executed during vertical blank time.

Y is used inside the Macro. All works great.


ldy #0


I tried to use the same code by a Subroutine.

ldy #0
jsr UpdateGRP1

It doesn't work good. The sprite movement is not smooth.

Is there something I don't know about these 2 way to use code?



Edited by Cisano
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        lda FrqFrameGRPX
        and MaskOne,y
        bne .end
        lda XposGRP1,y
        cmp StartOne,y
        bne .other
        lda #1
        sta CursorSpringOne,y
        jmp .opera
        ;lda XposGRP1,y
        cmp ArriveOne,y
        bne .opera
        lda #$ff
        sta CursorSpringOne,y
        lda CursorSpringOne,y
        adc XposGRP1,y
        sta XposGRP1,y
        lda StartOne,y
        cmp ArriveOne,y
        bne exit
        sta XposGRP1,y

The Macro has not the rts.

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Just some generic things to look for...



Jumping to the subroutine takes a few cycles.
Returning also takes a few cycles.

You said it is in the vertical blank code but is it time sensitive?



Storing the return address takes a few bytes of stack.

Is the stack big enough?



Some bank switching schemes trigger off subroutine calls (ie when you write/read the return address in the first few elements of the stack).

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1. I set a timer and the vertical blank time is not all used.

2. yes it is

3. no bank switching for now


I just moved the subroutine in another part of the cose, upper, and it works good.

It is the normality or there are solutions?


Edited by Cisano
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15 hours ago, Cisano said:

Penalty? You mean extra cycles?



Always when a branch or an indexed table access crosses a 256 bytes page the instruction takes one extra cycle.

To check this during assembly I have written a simple macro:

    IF >. != >{1}
      ECHO ""
      ECHO "ERROR: different pages! (", {1}, ",", ., ")"
      ECHO ""

If your branch moves backward, put this behind the branch and provide the branch address. If it is a table, put it at the end of the table and provide the table address.

Edited by Thomas Jentzsch
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