Search found 50 matches

by David G
Fri Sep 05, 2014 9:00 am
Forum: Emulators
Topic: JSZeddy
Replies: 47
Views: 19605

Re: JSZeddy

I wonder if the problem with Android Browser is that the soft keyboard by design does not appear unless focus is set to an input element. In Internet Explorer 8 the error is: Message: Object doesn't support this property or method Line: 18 Char: 2 Code: 0 URI: http://rullf2.xs4all.nl/jszeddy/zeddy.js
by David G
Fri Sep 05, 2014 3:30 am
Forum: Hardware
Topic: American ZX81
Replies: 2
Views: 924

Re: American ZX81

My ZX81 purchased in kit form back in the day (1981?) was the same. Channel 2/3 switch included.
by David G
Fri Sep 05, 2014 3:26 am
Forum: Emulators
Topic: JSZeddy
Replies: 47
Views: 19605

Re: JSZeddy

Is it a ZX81 emulator that runs in JavaScript?

With Android Browser I see some register boxes flashing, and eventually a K prompt, but there does not appear any way to enter commands.
With IE 8, I see only the register boxes and a script error.
by David G
Sun Aug 31, 2014 11:40 am
Forum: Development
Topic: ZxList 6, P file to BASIC conversion app
Replies: 29
Views: 9786

Re: ZxList 6.3 UPDATE, P file to BASIC conversion app

6.3 most importantly fixes the graphics codes. Both translation and presentation. (Will use the Sinclair font if it is installed on your PC). Attached to the first post of the this topic . This runs on Windows (including Windows XP, Windows 7 and Windows 8). zxlist63.JPG Changes: * corrected graphic...
by David G
Sun Aug 31, 2014 11:13 am
Forum: Development
Topic: Machine code analyis: Froggie 1983 game
Replies: 1
Views: 1130

Re: Machine code analyis: Froggie 1983 game

The Goodbye routine uses standard graphics characters placed in REM 8.

I wonder how he originally created this text -- with a special tool, or simply by trial-and-error on a the ZX81 keyboard?
Goodbye-REM8.JPG
Goodbye-REM8.JPG (14.91 KiB) Viewed 1125 times
by David G
Sun Aug 31, 2014 11:00 am
Forum: Development
Topic: Machine code analyis: Froggie 1983 game
Replies: 1
Views: 1130

Machine code analyis: Froggie 1983 game

Froggie (1983) has some interesting code -- and is a topnotch ZX81 game too. Froggie (1983) by Richard Braunton * Transitions between screens. Simple code, but very effective. See sample code in Transition Effects Code * Press A Key prompt animation screen at USR 22477 press-a-key.JPG * Goodbye disp...
by David G
Thu Aug 28, 2014 8:50 am
Forum: Emulators
Topic: New version emulator ZEsarUX-1.2
Replies: 1
Views: 2409

Re: New version emulator ZEsarUX-1.2

Runs on UNIX-type systems including Mac and Linux. Looks like an update to the topic ZX80/81/Spectrum emulator for Unix
by David G
Thu Aug 28, 2014 8:38 am
Forum: Development
Topic: Transition effects code
Replies: 1
Views: 838

Transition effects code

While analyzing an old game, I came across two interesting screen-wipe effects. I call them TRANSITION_CLOSE and TRANSITION_OPEN. * demo program is attached (TRANSITIONS.p) * assembly language source code in ZX-IDE format is attached (TRANSITIONS.asm) The machine code was found in Froggie 1983 by Ri...
by David G
Thu Aug 28, 2014 8:30 am
Forum: Development
Topic: Waiting some time!
Replies: 21
Views: 5304

Re: Waiting some time!

Many of the old games and programs used something like this:

Code: Select all

ld      hl,5000h ;delay factor
call    DELAYHL
...

DELAYHL:
        dec     hl
        ld      a,h
        or      l
        jr      nz,DELAYHL
        ret
by David G
Thu Aug 21, 2014 7:19 am
Forum: Development
Topic: tetris file for ZX-IDE
Replies: 1
Views: 839

Re: tetris file for ZX-IDE

A simple variation that can be made to the Assembly Language is to change the Keys used by the game from From S, D, K, L to the arrow keys v, <, > Change these lines cp 030h ;left (k) ... cp 031h ;right (l) ... cp 029h ;drop (d) to cp 21h ;left (5 "<-"") ... cp 24h ;right(8 "->"") ... cp 22h ;drop (...