Re: [cc65] Maximum application size

On Montag 19 November 2007, Ullrich von Bassewitz wrote:

> > 1) load the app to 0400 instead of 0800 and still start it normally?
>
> No. The compiled program has a BASIC header that does a SYS into the
> machine code. Loading it to $400 will prevent this. You can, however,
> carefully craft the executable image so that the BASIC header is still in
> place at $800. A probably better way is to place part of the BSS at $400,
> the casette buffer, etc.

a more pragmatic approach: make a custom startup code that has no basic 
header. make a custom linker script that uses the $0400 area for code. then 
after compiling pack your program (with either pucrunch or exomizer for 
example) so you can run it easily. that should let you use continous memory 
from 03something up to $cfff ($0200- with some fiddling, and if you dont use 
kernal)

> > 2) could i switch i/o-area and/or Kernal to RAM and use these areas for
> > code? (how much of the kernal is needed - i need to use file-i/o?)
>
> The runtime and C library assumes that the kernal is in place as it will do
> direct calls to the kernal ROM. You will have to select the functions
> you're calling carefully, if you're going to bank out the kernal.

i would suggest to use that area for graphics. a charset can be placed at 
$d000 for example, and then the screen at $e000. check how the fire demo does 
this (it does that, doesnt it? =P)

> > 4) i have a 2k const array for the charset - what is the best method for
> >  not wasting that memory, after the charset has been copied to its
> > final destination. Can i locate one of my global arrays of structs at the
> > same location?
>
> Yes. You can also place uninitialized data in the cassette buffer or other
> places.

the best would be to directly link it to its final destination - imho. no need 
to copy it around at all.

-- 

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