Sinclair ZX81 Emulator V2.1
===========================

This is  an emulator program for  the legendary Sinclair ZX81  homecomputer of
the year 1981. It  should work on all Atari computers  of the ST(E)/TT series.
The emulator needs  no hardware support, nevertheless  nearly everything works
and looks like on  the original ZX81. The ZX81 Emulator  ist Public Domain. If
you are a commercial  PD dealer, please report to the  author. Also note, that
no guarantee  is given that all  parts of the  ZX81 ROM Software and  the ZX81
programs may be copied freely. My address:

            Christoph Zwerschke
            Am Steinfeld 4, D-59379 Selm-Cappenberg, Germany

The ZX81 Emulator should come along with the following files:

            ZX81.PRG          ZX81 Emulator program
            ZX81.TXT          german documentation
            READ_ME.TXT       text you are reading now
            3D_LABYR.81       3D labyrinth game
            ASSDEMO1.81       assembler demo program 1
            ASSDEMO2.81       assembler demo program 2
            ASSEBLE.81        Z80 assembler
            DISASSEM.81       Z80 disassembler
            GALACTIC.81       "Scramble" game
            KONG.81           "Crazy Kong" game
            STUFFDEM.81       tool-kit demo
            ZX_GT.81          BASIC compiler
            ZX_STUFF.81       BASIC tool-kit

Files with the  extension ".81" are ZX81  programs. There may be  many more of
them, but you should copy at least the above specified programs.

The emulator has two "hot keys". The  first one is the "Undo" key, which opens
the emulator control box. In this  dialog box, you can change the ZX81 parame-
ters and do some  more control operations. If you like, you  can also load and
save the  parameters to existing ZX81  programs. The programs thus  are always
coupled to the suitable emulator parameters.  The ZX81 program files stay ZX81
compatible. You  can also load  and save ZX81 memory  blocks. A change  of the
ZX81 RAM extension  will become valid not  before the next ZX81  reset. If you
reset the ZX81, the parameters "ZX81.INF" and then the memory block "ZX81.MEM"
will be loaded automatically, if they exist.

The second "hot  key" is the "Help" key.  It shows you the layout  of the ZX81
keyboard. The Atari keyboard has the same layout in the ZX81 Emulator. You can
use the normal  Atari keyboard layout, if you press  "Alternate" together with
the keys.  You can  also lock  and unlock  this Atari  keyboard mode  with the
"CapsLock" key, which has  no other function in the emulator  because the ZX81
only knows capital letters.

ZX81 programs are  loaded and saved in the  usual ZX81 way with the   ZX BASIC
commands LOAD  and SAVE.  Instead of  the ZX81  cassette interface  the actual
GEMDOS file path is used. If you type in an empty program name, you can choose
a name using the file select box of the Atari GEM.

Share and enjoy!

            Christoph Zwerschke                                  June 18, 1993