[Coco] Byte Order Question

[Robert Gault]

David Gacke wrote:

> Hi All,
> 
> I've got a byte order question and I'm sure someone on here can give me
> the correct answer.
> 
> I'm trying to figure out the byte order of 16 and 32 bit register writes
> from a 6809 and 6309 
> 
> I'll use text characters as an example.
> 
> For instance, if I have a 32 bit value of say 0x41424344  ('ABCD') and I
> were to write that to video display memory, what would I see?
> 
> Would it be:
> 
> ABCD
> 
> CDBA
> 
> DCBA
> 
> 
> Also, what about 16 bit writes of say 0x4142..
> 
> Is it 
> 
> AB or BA?
> 
> 
> I need someone to give me a sanity check while I'm coding something.  :)
> 
> Thanks a bunch!
> 
> 
> Dave
> 
> 
> 
> 
> 
One further point to add to the other responses. It depends on whether 
the text screen is the low res 32 column or high res 40/80 column 
screens on a Coco3.

On the high res screens of a Coco3, every other byte is not text but an 
attribute byte. Text screens have the following format:
even byte - character, odd byte - attribute

attribute bits
0 - 2 background palette address
3 - 5 foreground   "        "
6     underline
7     blink