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From: Pigmy (all posts)
Date: 2001-01-25
Subject: Re: Merry Xmas!

On Wednesday 24 January 2001 20:23, you wrote:
> Paul has some problems with Pirates, because the main program part is
> located from 0800 till Idontknowbutsomethingliketheendofc64basic:), so
> it is much bigger than it can be on Plus4... :(
>
> SO any suggestions how to reduce it?
>
> Take care, LVN

C64 basic programs normally start at $0801, because the character mode screen is at $0400-$07e7 (the color memory is at $d800-dbe7). PLUS/4's screen is at $0c00-$0fe7, the color memory is at $0800-$0be7, so the BASIC code is stored from $1001. Pirates is a BASIC program with some (or a lot of :) machine code routines, graphics, so... At first you should have to find a place for the BASIC code. The biggest problems are the non-basic parts: character tables, machine code routines, graphics, etc., because if the BASIC code is moved to $1001 the end of the code can overwrite the other parts of the program. You should check it, if you have enough place then you're lucky :) An other way is to leave the BASIC code at $0801 and put the characted mode screen to somewhere else. Maybe it doesn't use character mode screen at all, just graphics mode... I don't know. But then you have to find a place for the graphic memory too :) Well, you have to find a tricky way to convert it. By the way... Doesn't it use sprites?

Pigmy