22 Mar
2002
22 Mar
'02
1:18 p.m.
I've got a primitive disassembler, included with the PAULMON2 monitor,
intended to be loaded as an add-on under the control of the monitor, and I
thought I'd parse the input from the console in modes, using table-lookup
during the character-by-character input. That will be simple but not
particularly efficient of memory space. Current generation memory sizes don't
impede the process much, though. The 89C420 has a potential for an 80K
program memory with the on-chip 16K mapped in and out under control of the
SFR's. SInce I have plenty of assemblers and compilers, just not a
line-by-line assembler source for incorporation in the monitor, I'm probably
going to have to roll my own.
Another thing I'd like to find is some 'C' source for an MSDOS-compatible
file
system. There's no reason an 805x development effort has to be PC-based, and
even if it is, there's certainly no reason for it to be tethered to a PC for
every little tweak.
The 89C420 runs fastest out of external memory, allowing 20ns code space
fetches except on page-boundary crossings, and 40ns data space accesses.
With one instruction cycle taking however long it takes to fetch it, I'd say
that's almost fast enough for an old established architecture like the 805x
core. This one executes a single cycle instruction in a single system clock
cycle and it divides the input clock by 1, in the default.
If you work that architecture, this one's certainly worth a look, though it's
not cheap. A hot-rod seldom is.
Dick
----- Original Message -----
From: "Bob Shannon" <bshannon(a)tiac.net>
To: <classiccmp(a)classiccmp.org>
Sent: Friday, March 22, 2002 5:00 PM
Subject: Re: Source code for 805x line-by-line assembler?
805x processors cannot (without external hardware)
write to program memory,
so any
line assembler would be dependant on some (common)
hardware tricks to write
to
program space.
Most 805x applications are single chip anyway, so this is not too common.
The
closest thing that comes to mind is an 805x Forth that
~may~ have an
assembler
extension.
John Chris Wren wrote:
> D'oh! I feel stupid. Don't ask me why I read 65xx with you asked
about
> 805x. I've been writing 805x for about 15
years, and I've never run
across
> one. I've though about writing one from time
to time, but never got
around
> to it. Since I usually have a pretty tight
embedded system, I use all
host
> side tools. If you write one, I'd be
interested in looking at it.
>
> --John
>
> > -----Original Message-----
> > From: owner-classiccmp(a)classiccmp.org
> > [mailto:owner-classiccmp@classiccmp.org]On Behalf Of Ben Franchuk
> > Sent: Friday, March 22, 2002 0:05 AM
> > To: classiccmp(a)classiccmp.org
> > Subject: Re: Source code for 805x line-by-line assembler?
> >
> >
> > John Chris Wren wrote:
> > >
> > > The reason for that is generally memory. The Apple II
> > monitor had a nice
> > > little one built in, and it was a work of art, as far as the opcode
> > > compression and decoding table went. One time (many years
> > ago), I stripped
> > > that portion out of the Apple monitor for another personal project.
You
> > > could do the same. It wasn't very
difficult to do, just a bit
> > of typing.
> >
> > The 6502 has a very simple and regular instruction set that is easy to
> > encode.
> > What is 805x controler like?
> >
> > > > The 805x microcontrollers have been around since the mid-80's,
> > > > yet I've never
> > > > seen a monitor program for them with a "quick-and-dirty"
line-by-line
> > >
assembler in it as many of the debuggers for the MOT monitors
> > > have. Do any of
> > > you guys have a source file of a line-by-line assembler for the
> > > 805x series
> > > that can easily be adapted for inclusion in a monitor?
>
> Lets not forget a version of basic for the apple was all hand coded with
> no real source?
> --
> Ben Franchuk - Dawn * 12/24 bit cpu *
> www.jetnet.ab.ca/users/bfranchuk/index.html
>