Re: [cc65] Which zero page adresses may i use?

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From: Ullrich von Bassewitz (
Date: 2003-11-24 00:00:02

On Sun, Nov 23, 2003 at 11:47:32PM +0100, Benjamin Bahnsen wrote:
> Which parts of the zero page may I use and which ones does the runtime
> environment use?

This is determined by the linker config. Several zero page variables used by
the compiler and runtime may also be used by your own assembler subroutines:

        ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, tmp4, sreg

These variables are not expected to be saved across function calls.

> I there a way to use the memory configuration file to say: I
> want to use $F0-$FF, please don't let the program use these adresses.


> Does it mean, that the compiled program only uses $02 - $1C?

If this is the linker config used by your program (and it looks like it is the
case) then: yes.



Ullrich von Bassewitz                        
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