Re: Apple IIe / ProDOS /

[dempson@actrix.gen.nz (David Empson)]

Jeff Brielmaier <Jeff.Brielmaier@juge.com> wrote:

> e >> I replaced the 6502 with a 65802 a long time ago, it's a
> e >> better replacement chip than the 65C02.
> e >
> e >What is a 65802 and why is it better? Is it a replacement for the
> e >65C02 in my Apple //e enhanced?
> 
> The 65802 is a 65816 packaged in a '6502 compatible' package.
> 
> Other than Merlin+, I am not aware of any other software that you actually
> make use of the extra (65816) instructions that the 65802 has.

I haven't heard of "Merlin+".  The product is actually Merlin 8/16,
which includes four assemblers: Merlin 8 for DOS 3.3, Merlin 8 for
ProDOS, Merlin 16 and Merlin 16+.

Merlin 8 runs on a 6502.  The DOS 3.3 version runs on a 64K machine,
while the ProDOS version requires a IIgs, IIc or 128K IIe (as does
Merlin Pro, if I remember right).

Merlin 16 requires a 65802 or 65816, and is about five times faster than
Merlin 8.  It also requires 128K.

Merlin 16+ is a IIgs native application which will not run on an 8-bit
machine no matter what processor you put in there.  It is about twice as
fast as Merlin 16, and has a lot more capabilities.


For the technically minded: Big Mac, Merlin, Merlin Pro and Merlin 8 all
make use of the Sweet-16 interpreted instruction set to assemble your
program.  Since Sweet-16 is much more compact than 6502 code when
dealing with 16-bit data, the end result is a smaller assembler and more
space for your source and object code.  The tradeoff is speed - Sweet-16
is slower than 6502 native code.

Merlin 16 can use the native 16-bit capabilities of the 65802 or 65816,
so there is no need for the interpreted Sweet-16 code.  The assembler
may end up being a little larger (probably not much), but runs _much_
faster.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand