From: Ullrich von Bassewitz (uz_at_musoftware.de)
Date: 2004-01-24 10:44:37
Hi!
On Sat, Jan 24, 2004 at 01:59:16AM +0100, Benjamin Bahnsen wrote:
> I used the second way you described, because i want to use the variables in
> assembler, too. It works perfect, thanks. But i had to rewrite the
> memory.cfg to increase the zero page size. The default size was 1ah. I am
> not very familar with the kernal functions of the c64 and which zero page
> addresses they use. I am wondering, if it is a problem to set the zero page
> size to (for example) f0h. I am still able to use file-I/O-functions or the
> standard-I/O-functions of CC65? Or do these function use kernal calls, which
> change the zero page?
You cannot just increase the zero page size in the memory configuration. While
this works as far as the linker is concerned, you will
- overwrite the current contents of these variables (something the kernal
will not like), and
- since the runtime communicates with the kernal via these variables, you
may break runtime routines.
As a general rule, you cannot use memory that you don't own (at least not
without some precautions). This is a common rule when coding in assembler, and
it is also true when coding in C.
Regards
Uz
--
Ullrich von Bassewitz uz_at_musoftware.de
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