Also, rename CLRLN to NEWLN and make it clear that it's only called
on entering a new line. This way, we can set Z offset in there for
the TI-84+ LCD driver.

Instead of clearing the rest of the line on a _lf, it's simpler
to just clear any new line we're entering into.

Rename ROWS to LINES (it's what VE uses). Also, don't use COLS and
LINES as immediates in the Grid subsystem: we expect those words to
be available at runtime.

The goal is to offload the SMS VDP driver a little bit.

It isn't used in there anymore. Moved it to VE, the only place
where it's used.

The '2' key on my PS/2 keyoard never worked on Collapse OS, I
wasn't sure why. I thought the keyboard was broken, but then I
tried another one, still broken. But it's only the '2'!

The KC sent is 0x1f. Is it a timing problem with the ATtiny? I
have yet to wire my prototype for logic probing. Meanwhile, let's
apply a band-aid.

Previous instructions would only work with an AT28C64. Now, it also
work with an AT28C256.

Recipes contain bits and pieces of hardware-related knowledge, but
these bits feel sparse. I've been wanting to consolidate hardware-
related documentation for a while, but always fell at odds with the
recipes organisation.

We don't have recipes anymore, just a /doc/hw section that contains
hardware-related documentation which often translate to precise
instructions to run Collapse OS on a specific machine.

With this new organisation, I hope to end up with a better, more
solid documentation.

There are many situations where it can be useful. Worth it.

This allows us to remove AMOVE* words.

This would be useful, for example, to allow the assembler to write
straight to an AT28 EEPROM without going to RAM. This would be a
life saver in machines with tight RAM such as the SMS.

I'm pretty happy about how lightweight the implementation turns
out to be.

They were only used in the ti84 recipe and were not worth their cost.

also, verify all 3 first bytes of SPI commands. I'm not sure why
I wasn't doing that, probably because I was getting a lot of AVR
err and thought that only 2 bytes of the cmd were echoed. But now,
with a reliable SPI setup, verifying 3 bytes seems to work.

After many trials and errors in reliably accessing AVR chips through
my SPI relay design, I resigned myself to accepting 125kHz communication
speed with it. I find the complexity of solutions allowing to keep 250kHz
speeds to be excessive.

Also, remove needless argtype in CALL and RET

Adding a delay such as the 20ms one we have in AVR programmer's
initialization routine is tricky without a word like TICKS.

This implementation is highly inaccurate, but more accurate and
reliable than a "ballpark" DO..LOOP...

ABORT" doesn't work in xcomp.

Also, improve xcomp docs and fix misdocumentation.

That slims down blkfs a lot.

Also, remove leftovers from previous move.

And move its doc to doc/asm.txt

Also, move doc to doc/asm.txt.

Also, fix the pcat recipe which was broken since the overlay change.
I hadn't noticed it because I didn't have to rebuild the MBR.

The idea is to consider assemblers as "runtime" apps instead of
placing them in the "bootstrap" section of the blocks. These apps
will be used for much more than bootstrapping.

Moved its documentation to doc/asm.txt and made its code blocks
more compact.

This marks the end of wordrefs in stable ABI. Nice.

The ":" now takes care of scanning for ";". Conceptually, having
";" as an immediate word is slightly simpler than the approach in
this commit, but when bootstrapping is involved, this simpler
approach gets murkier.

Moreover, it got even murkier-er when trying to de-stabilize EXIT,
so here we are.

This duplicated feature existed because of bootstrapping issues
with LIT", but again, with careful threading, we can clean things
up.

We can now have a proper "Collapse OS" prompt :)

When writing the xcomp documentation, I realized that with careful
threading and by accepting a bit of code duplication in the xcomp
toolset, I could de-stabilize a couple of words.

(n) and EXIT are a bit trickier, but I think it can be done. It
would be nice to get rid of stable wordrefs...

Working on programming AVR chips exposes a glaring omission in my
first design of the SPI Relay: not allowing multiple devices make
this task hard. I constantly have to unplug my SD card before, plug
the AVR chip holder, then play a bit, then unplug the AVR holder,
then replug the SD card...

My prototype for a SPI relay design is built, but I haven't tested
it yet. I need to adapt the code first, which is what I do here.

When the prototype is tested, I'll update the SDC recipe with a new
schema.

The batch mode thing seems to have been caused by bad timing on my
prototype. Now that I've corrected it, live interaction seems to
work fine.

Although the SPI Relay driver is RC2014-specific, the SD Card driver
is generic enough to be a subsystem. That's the second subsystem we
add and this warrants, I think, the formalization of a new concept:
protocols.

I've changed my mind about having documentation in-system. It doesn't
serve much of a purpose and make blkfs significantly heavier.

This commit is the first step in writing a documentation outside of
the blkfs.