[Coco] [Color Computer] Holy Mods Batman!

[James Diffendaffer]

--- In ColorComputer at yahoogroups.com, "John R. Hogerhuis"
<jhoger at p...> wrote:
> > 
> > I haven't seen the Zaks book but I'd love to check it out.  
> 
> I have it -- but the Zaks book isn't that great. Most of the book is
> just a reference.

Maybe I have seen it.  If it's what I think it is, it's a combination
of all the stuff in the Zilog data books but in a better format and
better diagrams.


The 6809 Assembly Language Subroutines wouldn't offer anything I
couldn't write myself.  All the other books in the "Subroutines"
series seemed to duplicate the same routines from book to book.  HEX
conversion, stuff like that.  But it's good to see other people's code
when you're learning and being able to compare routines from one book
to the next makes porting code easier.


Anyone that doesn't understand why the 6809 was considered the king of
the 8 bits should look at how things were done on the Z80 and 6502. 

The 6502 was too simple.  Building a compiler for it is a nightmare. 
Just check out how much code the cc65 compiler cranks out to do anything. 

The only 8 bit CPU besides the 6809 I could stand was the Z180
(upwards compatible from the Z80).  It was just passable for use with
a C compiler even though it was better than the Z80.  The number of
instructions required to pass variables on the stack (like C) is nuts.


When you look at modern 8 bit CPUs the 6309 is hard to beat.  All it
needs is a higher MHz and the ability to address more memory... but
the instruction set is sound.  
The 65816 is miles ahead of the 6502 but to benefit you are writing
lots of new code.
The eZ80 is faster than the Z80/180 but still suffers from the same
code density limitations as the old versions.
The Z-World Rabbit modifies the Z180 instruction set so that it fixes
the problems and it's actually a great CPU... but it's not code
compatible.  For running C code it's a great CPU and I'd like to build
a machine based on it.







Brought to you by the 6809, the 6803 and their cousins! 
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