Date   : Fri, 20 Dec 2013 09:15:38 +0100
From   : anders.carlsson@... (Anders Carlsson)
Subject: Physical colour numbers

J.G. Harston wrote:

> Yes, the C64 host interface rearranges the native hardware colours into 
> the standard RGB values (mdfs.net/BBCBasic/C64)

Cool, although seasoned C64 programmers switching to BBC BASIC will get 
mightily confused. Is it possible to have a setting, an OS byte to select 
palette between strict RGB order and hardware order? I understand it would 
break compatibility, but assuming the C64 port takes advantage of the custom 
chips in other ways, it would risk to break compatibility anyway.

> [VDP] a rather eclectic choice of names

I made up those on the fly. For reference, I just cycled through all 
possible background colours on my VTech Laser 2001 computer which was in 
front of me at the moment. I agree that at least two of the orange hues 
should match some kind of red, and that it might differ from each type of 
VDP based computer exactly how the colours are displayed.

For that matter, I just conducted a series of benchmarks and found that 
while the Laser 2001 with a 2 MHz 6502 has a reasonably fast BASIC, it 
doesn't quite hold up to the speed of BBC BASIC. Then there is the console 
version, CreatiVision which due to lack of CPU RAM has to use its VDP memory 
to store BASIC programs. For various reasons, it makes it super slow on 
everything but math. There are discussions to manufacture RAM expansions and 
an improved BASIC of some kind, perhaps this could also be a future 
candidate for porting BBC BASIC as it already runs the "right" CPU and has 
potentials as shown from benchmarking the 2001 computer model.

Best regards

Anders Carlsson