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   UltrascreenNEC 1.4LT (C) 1987-2026 Ultrasoft / Daniel Born / Gary Weber
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60-column by 10-line display driver for the NEC PC-8201/8300 -- Lite Fast edition

Many thanks goes to Daniel Born and Richard Ecklerlin for making this a
reality!

This is the LITE FAST edition of UltrascreenNEC 1.4.  Like the plain Lite, it
renders the very same crisp 60x10 small-font display and keeps the simple,
Model-100-style line editor for BASIC in place of the full-screen editor: you
type a line, Backspace rubs out the character to the left, and ENTER submits
it.  Just as on the original Ultrascreen100, the Left-arrow key doubles as
Backspace.

What this edition adds is a much faster TEXT experience.  The small font used
to redraw a lot of pixels on every keystroke, so this build keeps a shadow
copy of the screen and only repaints the cells that actually change.  Typing
and scrolling in TEXT now keep up the way they do in the full edition.  The
cost is that one small screen buffer, so it lands at roughly 3.8K resident:
bigger than plain Lite (about 2.9K), but still noticeably lighter than the
full editor (about 4.8K).

LOADER.BA - Tokenized BASIC loader/relocator for creating USCNLX.CO from
            scratch. This will create USCNLX.CO at whatever base-address
            you wish.

LOADER.DO - Text-flavor of the Basic loader/relocator

USCNLX.CO - Machine language ready-to-load into your NEC machine, you can
            bypass the loader entirely if you just want the fixed-location
            program which loads at 58435.

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How to install
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There are two ways to install it: an automatic loader that does the work for
you, or a manual load if you'd rather place it yourself.

** The easy way: the loader

The simplest path is UltrascreenNEC Lite Fast's loader, LOADER.BA, which works
just like the original Ultrascreen100 loader on the Model 100. It carries the
whole program inside itself, so LOADER.BA is the only file you need to transfer
onto your PC-8201A or PC-8300.

Load LOADER.BA and run it. It asks:

   Install under address (ENTER=max 62336)

Press ENTER to tuck it up as high as memory allows (recommended), or type an
address if you want it somewhere specific. It relocates UltrascreenNEC Lite
Fast to fit, saves a ready-to-run USCNLX.CO built for that spot, and hands you
back to the main menu. Run that USCNLX.CO and you're straight into 60x10 -- no
CLEAR to work out and no address math to get wrong.

** The manual way

If you'd rather use the pre-built USCNLX.CO (it loads at 58435), transfer it
onto your machine, then from BASIC park high memory at the load address so the
resident code has a safe home:

   CLEAR 0,58435

Now load and run USCNLX.CO the way you'd launch any machine-language program
(for example, selecting it from the main menu).

** Either way

Once it's installed you're in 60x10, and TEXT, TELCOM, and BASIC will all be
60 columns by 10 lines. Type SCREEN 0 any time to go back to the normal 40-
column display, and SCREEN 1 to return to 60.

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Using Ultrascreen Lite Fast
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When you enter BASIC, TEXT and TELCOM, it's just active by default in 60x10
mode.

Because this is a Lite edition, BASIC line entry uses a plain single-line
editor instead of the full-screen editor: Backspace and the Left-arrow key
both rub out the character to the left, and ENTER enters the line. INPUT, LINE
INPUT and direct-mode commands all behave the same familiar, Model-100 way.

TEXT, on the other hand, is the fast one here: it feels as responsive as the
full edition, so editing documents in 60x10 is comfortable rather than sluggish.

You can temporarily disable the 60x10 display from BASIC with this command:

   SCREEN 0

That flips your computer back into 40x8 mode, which persists in all three ROM
programs. BASIC, TEXT and TELCOM will run just as they did before. However,
you will know Ultrascreen is still installed and waiting to be reactivated
anytime because you'll see "Basic  Text  Telcom" listed in mixed case in the
main menu. To reactivate your 60x10 mode, go to BASIC and type this command:

   SCREEN 1

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How to uninstall
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From BASIC:

   CLEAR 0,62336

Answer Y to the "REMOVE Ultrascreen? (Y/N)" prompt and UltrascreenNEC Lite Fast
unhooks itself, resets the screen to 40x8, and hands all of its memory back.
Answer N and it stays put. (Under the hood, any CLEAR that would reach up into
UltrascreenNEC Lite Fast's reserved memory triggers the prompt; 62336 simply
hands back the maximum.)

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Gary Weber
email: gary@web8201.com
www.web8201.com
