Re: [cc65] Setting aside Character Set ram

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From: Brian Bagnall (bbagnall_at_mts.net)
Date: 2002-10-22 04:13:51


It really turns into a pain if I try to address memory higher than the first
16kb. Would there be any problems if I changed the START variable in the
config to $FFF, leaving 2048 kb for a custom character set near the start of
RAM? From what you described about the basic header, it seems this would not
conflict with that area.

Also, you mentioned a graphics package would be included in the next
release. Would this handle custom character sets, and when do you expect the
next version to be released?

- Brian

----- Original Message -----
From: "Ullrich von Bassewitz" <uz_at_musoftware.de>
To: <cc65_at_musoftware.de>
Sent: Saturday, October 19, 2002 12:37 PM
Subject: Re: [cc65] Setting aside Character Set ram


>
> Hi!
>
> On Fri, Oct 18, 2002 at 02:51:09PM -0500, Brian Bagnall wrote:
> > First, do I alter c64.cfg in the doc directory? (seems strange that it's
> > stored here)
>
> It is in the doc directory, because this is just a copy of what is
compiled
> into ld65. It is thought as a reference and may be used as some sort of
> documentation. To use it, create a copy in your program directory and use
>
>         -C config-file-name
>
> instead of
>
>         -t c64
>
> when calling the linker.
>
> > Second, you mentioned the program is stored from $801 to $D000 but the
> > c64.cfg file says $7FF to C801. Which is right?
>
> The config file says
>
>     RAM: start = $7FF, size = $c801, define = yes, file = %O;
>
> So the RAM area starts at $7FF (this includes the two byte load address on
> disk, so the actual start address is the BASIC start, $801) and is $C801
in
> *size*. If you add both numbers you get
>
>         $7FF + $C801 = $D000
>
> which equals the end address I've mentioned.
>
> > Third, do you recommend setting aside memory at the start or end of this
> > block?
>
> Setting aside memory from the start of the block is problematic, since
> programs generated with the default setup for the C64 will load as BASIC
> programs and have a small BASIC header (to check that, load a cc65
generated
> program and enter "LIST" before running it). The easier way is probably to
use
> memory at the end of the former RAM area. This brings in another problem:
The
> data must be moved into this range somehow. However, for most people, this
> should be easier to solve than changing the cc65 startup file.
>
> Regards
>
>
>         Uz
>
>
> --
> Ullrich von Bassewitz                                  uz_at_musoftware.de
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