VCF Requests

From: Hans Franke <Hans.Franke_at_mch20.sbs.de>
Date: Tue Aug 29 06:49:49 2000

> > > The PC6 was a disapointment :-(. It's a Casio clone, of course (I forget
> > > which model). It's got the same BASIC (essentially) as the PC4, with the
> > > same 10 'program areas' and common variables for all programs. It does
> > > have more memory (8K IIRC).
> > PB 1000 ?

> No idea. I don't bother too much with Casio machines...

> It's a black clamshell case, hinged along the back edge (a bit like most
> palmtops, e.g. the HP95LX, etc). The upper part has a 1-line alphanumeric
> LCD and a 3 row membrane keyboard, containing the letters (it's
> essentially QWERTY layout) and some special keys.

> The lower part has the numeric keypad, 'calculator' function keys (SIN,
> LN, etc) and the power swtich (a slide switch at the far left).

I belive it is the PB1000 model

> > > The 'assembler' is a cheat!. It's not an assembler for the PC6's CPU,
> > > it's an assembler for a mythical 16 bit CPU. There's also a simulator for
> > > said CPU in the machine so you can run your 'assembly language' programs.
> > > But it's pretty limited in what it can do, and you certainly can't access
> > > hardware features of the PC6.

> > Well, as you prefer - I thought of the assembler as quite nice
> > tool to write programs with faster execution than in basic,
> > and you could access (most?) hardware - I did some nice graphic
> > games with it, impossible in basic.

> That's exactly the point. The main use of assembly language (especially
> on these small machines) is to allow you to do things that you can't do
> from BASIC (display non-standard characters, detect multiple keys down at
> the same time, have key down and key up 'events', toggle I/O port lines,
> control individual dots on the display, etc, etc) or to do things faster
> than BASIC would allow.

> Now, this 'assembler' didn't do any of that. It was slow. As slow as
> BASIC IIRC. And the _only_ I/O was to input a value to one of the 4 GR
> registers (either in decimal or hex) or to display one of the GR
> registers in decimal or hex, in a predermined format (it was something
> like 'GR0(10)=1234'). Not even the ability to output a string of characters.

Maybe I useda wrong wording here, I _did_ a graphics game on the
Casio using the assembler - and it was quite faster than the
same game in BASIC.

> And, of course, no access to the real machine's hardware.

Depends how to define access.

> > Also, when is an assembler real ? Maybe with an exeptinon of
> > early PDP8s, where the coding did realy trigger the hardware

> Hmmmm.... I've never had any problems visualising what a given assembly
> language instruction does to the real machine, at least not at the level
> of the lowest available documentation.

> In other words, if I have the gate-level scheamtics and the microcode
> flows (if appropriate), then I can work out what an instruction does to
> each gate in the CPU. If it's a micro, well, I can work out what will
> appear on the buses, and thus what the rest of the hardware will do. Etc.

And given the same documentation you can do it for the Assembler
instructions in here ... the difference between a 'real' assm
code interpreted by some micro code, and a the Casio ting, run
by a interpreter written in 'real' assm is non existent the
behavior is determistic in both ways. Even when you consider
that you may now have 3 levels (Hardware/Real/Pseudo) is not
uncommon, there have been microprocessors with 2 build in
levels of interpretation The 'real' assm code was run by
microcode, where some microcode instructions itself did use
'nano'code to perform. Of course you may name it as some
special kind of sub function code - bust still you may use
the same abstractions on any scheme (like the Casio).

Gruss
H.

--
VCF Europa 2.0 am 28./29. April 2001 in Muenchen
http://www.vintage.org/vcfe
http://www.homecomputer.de/vcfe
Received on Tue Aug 29 2000 - 06:49:49 BST

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