test please delete

[EqualOpportunities]

Good morning.

I am trying to decide whether I should go to sleep, or stay up and watch the Australia v New Zealand cricket that is going to start in about an hour and a half.

Watch the Cricket - without doubt.

[BrowneIssue]

Me, I'm full of the flu and flu remedies that aren't doing a damned thing to ease it, so I'm off to bed to wallow in my own snotty misery.

Goodnight all

There is no way that we will hit 50000 tonight if Diver is going to bed.

Nope. You're right there. Driveller-extraordinairre.

[BrowneIssue]

OK I’m back anyway what did I miss?

#46000





Well done!

[NickFitz]

It's ever so difficult to remember a world where Pong was an innovative & interesting game... followed by the tank battle game...

BattleZone

If you want to play it again, search for MAME (Multiple Arcade Machine Emulator)... then find somebody who's got the ROM images

It's the Real Thing (TM CocaCola Corp) in that it emulates the original hardware (6502 at 1MHz with custom vector graphics hardware for the display, in BattleZone's case - same as Asteroids), and runs the original ROMs... you even have to sit through the hardware self-test routines, as if you'd just powered up the machine

And you can configure the DIP switches that control the scores at which bonus tanks and suchlike are awarded - or make it 50p a game, if you want (configure CoinSlot2...)

The ROM images are copyrighted so it's illegal to distribute them and the download sites keep getting shut down - so even if you PM me I can't possibly give you a copy of my copy

Pong was mainly done in TTL rather than software

[NickFitz]

The only processor for which I made the effort to memorise the assembler codes ... initially on something from USA that came as a bag of components + circuit diagram and then again on the ZX Spectrum.

I was always 6xxx on 8-bit processors (6800, 6502, 6809), and only learnt the Z80's whimsical ways when I was working as a games programmer, initially porting 8-bit stuff to 16/32-bit platforms (8/16 bit, in the case of PClones). On the Spectrum-specific front I remember that there was a return instruction in the ROM that people used to jump (or branch, perhaps) to because, bizarrely, by branching (or possibly jumping) (under certain circumstances) to a known return instruction of this type, you saved a byte.

Then Sinclair put some bug fixes in the ROM and started shipping that version in new Spectra, unannounced. The return had moved...

OK, so I'm a coward.

I have her on my ignore list

You're missing out

and have done so since I got a tirade of abuse a few weeks back.

They're the best bits... it's her way of being friendly

I dunno. These kids and their cheerful assumptions about 8-bit words...

Well, the PDP8/e had 12-bit words and liked octal, being DEC and all that, and these principles carried on into the PDP-11 series... In the late eighties I had a PDP-11/34 in my flat, with two RK05 disc drives... it was nearly as big as the fridge. When I implemented FORTH in PDP-11 assembly language, I initially tested the bootstrap code by entering it, in octal, into memory using the buttons on the front panel...

I've just remembered a third - a C programmer who said 'informationals and warnings don't count'. This was the bod that added 'one' or 'two' or 'four' or whatever to a bit flag to turn a bit on and added it again to turn it off. I spent an afternoon trying to explain what XOR was for but he was having none of it. The bugs he caused used to drive me mental. (E.g. every 16th press of RETURN would alternately turn the cursor off or on.)

We farmed out a conversion from (IIRC) the Spectrum to the C64 to a local teenager who, in principle, was a competent programmer.

The test versions he delivered always suffered from dreadful sprite flickering (almost impossible to achieve on the C64) which he dismissed as an inevitable consequence of implementing such complex graphical operations, which had in any case been optimised for the Spectrum way of doing things.

Upon finally taking the code in-house, in the vague hope of actually turning it into a deliverable product, we discovered such delights as the way he added 100 to the score, which was to loop over the addition of one to a 16-bit value a hundred times.

To give you an idea...

.add100toscore
LDA X, #100
CLC
.start
LDA score
ADC #1
STA score
LDA score+1
ADC#0
STA score+1
DEX
BNE start
RTS

As opposed to

.add100toscore
CLC
LDA score
ADC #100
STA score
LDA score+1
ADC #0
STA score+1
RTS

[EqualOpportunities]

You on the night shift or something Chimp?

[NickFitz]

You on the night shift or something Chimp?

He had similar routines for adding 200 or 1000 or whatever to the score

The reason for the sprite flicker was that it could take up to a quarter of a frame (about 5ms in the UK) to update the score as necessary

[NickFitz]

You on the night shift or something Chimp?

Oh, Hi, BTW

[EqualOpportunities]

Oh, Hi, BTW

Hi

It's slow in here this evening.

[NickFitz]

Hi

It's slow in here this evening.

Quite restful, though.

I was in Stonehenge at midnight once, just a few candles here and there and some people gently drumming or playing bodhrans - autumn equinox eve 1987, IIRC.

There weren't many of us there, but it was conducive of a contemplative state of mind.

Sometimes slow is good