Re: Uther card works on Apple IIplus with contiki

[Oliver Schmidt <ol.sc@web.de>]

Hi Rob,

>> The "downlevel" version is known to be unable to load both the web
>> browser and a screen saver.

>Do you have any idea why this is so?

Of course - as I did it ;-)

>Both machines have the same amount 
>of memory and if anything the "downlevel" version should be simpler. 
>Does the //e version make use of 65c02 instructions to reduce memory usage?

1. Your guess is right. The cc65 C compiler allows to produce 65C02
instructions which reduce the code size. In fact even the assembler
parts of the cc65 C-Library are smaller because they often exist in an
optimized 65C02 version.

2. Contiki contains general purpose screen drawing code written in C
that creates windows from two horizontal lines, two vertical lines and
four corners. This code is used for the "downlevel" version while the
mousetext version uses custom code that creates a window by calling a
single C-Library assembler function available only for mousetext.
Beside that the custom code does no window clipping. That further
reduces code size but increases flicker - which I classified
acceptable due to the general high(er) drawing speed.

Best, Oliver