Spectrum Computing

You could maybe make use of the LOOK-VARS routine from the ROM. Something like this:- look_vars equ $28b2 ch_add equ $5c5d ld hl, (ch_add) push hl ld hl, varname ld (ch_add), hl call look_vars jr c, notfound ; do something with the variable here notfound: pop hl ld (ch_add), hl ret nc rst $08 db $01...

Is there a way to get a Maxduino/Tzxduino to output OTLA encoded content? Yes, although the TZXDuino/MaxDuino firmware can't do it... A while ago I wrote my own firmware for the TZXDuino as a proof of concept which could output TZX files created by OTLA, which comprise of a single ID15 (Direct Reco...

Assuming you mean the Magnum Light Phaser, it uses KEYPAD port (AUX on the +2A/+3).

Gilligan's Gold - It's demonstration mode always reminded me of a slapstick comedy sketch you'd expect to see on the the likes of The Goodies.

EDIT: Just took a look at it, and it does seem it's actually a handful of different scripted runs. Guess I didn't know any better when I was a kid!

Removing the author's credit is just plain cynical IMO. The only reason for doing so I can think of is in the hope people will mistakenly believe the person who modified a game was also the original author, whilst being able to fall back on the argument of "Well, I didn't but my name in it's pl...

Not so straightforward. You're paging a whole 16k in and out, not just the screen. No, the memory at $4000-$7fff is always bank 5, you're simply toggling where the ULA fetches it's data from. Obviously you need to page in bank 7 @ $c000 to write to the shadow screen, but that's no different from pa...

I didn't quite realise (either) how many enhanced 128k games there were, where they had larger or more detailed playing areas, for example. In my head they were mostly just additional 128k music or reducing the need for multi-loads. Same here. I wonder why this was even possible, at a technical lev...

The Coupe was a nice machine, but had a 6Mhz Z80 (before even taking contention into account) trying to push pixels around a 24K display file (at least it was linear, though!). It really could have done with hardware sprites/scrolling... something which the Next addresses. Nope, the Next doesn't ha...

the sam coupe could have been remade though, right? The Coupe was a nice machine, but had a 6Mhz Z80 (before even taking contention into account) trying to push pixels around a 24K display file (at least it was linear, though!). It really could have done with hardware sprites/scrolling... something...

spider wrote: ↑Fri Jun 18, 2021 1:36 pm "...nasty 3 inch drives..."

I'm not sure Sir Clive would have risked turning the conversation toward Microdrives by mentioning storage devices.

Yup, BCDs are the way to go here IMO. As such, you need 3 x 8-bit registers (5 digits required, 2 digits per register) when calling the addition routine. For example it you wanted to add 43276:- ld c, $04 ; it's important to define these values in hex ld hl, $3276 call add One possible implementatio...

Where are you going with your fetlocks blowing in the... wind?

I don't see it clarified, but does it work with all VGA monitors, or is it like the Atari STs which need specialized low Khz ones? I also have a couple of VGA monitors for my retro PCs. Yes, it can scandouble 15Khz RGB and output to VGA monitors - in which case you can simply use a standard VGA cab...

I have a couple of CRTs I use for retro hardware. Thanks for the link, I'll study it now. If you do decide to get one, one thing I'd recommend against buying is the DIN9 to SCART cable. In my experience, the image quality is far better using a MiSTer VGA to SCART cable (which also works just fine o...

I hadn't realized that they are this expensive. Might as well as stick with the RetroPie or Lakka Another option would be the SiDi . Much less expensive and comes ready built in an acrylic case. It's FPGA is less capable than the one in the MiSTer but it can handle 8-bit/16-bit computers and consol...

Juan F. Ramirez wrote: ↑Wed May 19, 2021 12:54 pm

FTFY

Are you trying to pass it back to BASIC?

If so, the return value of a machine code routine needs to be in BC, so you should replace LD A,(HL) with:-

The action replay/slow motion features in BMX Simulator.

You can also have a set of flag bits for each base word indicating valid common prefixes and suffixes e.g. -ing -ed over- under-

There are quite a few badly named mnemonics in Z80. For instance there's " ADC A,B ", " ADD A,B ", " SBC A,B ", " SUB B ". Why??? Well, as there's no " SUB HL,rr ", it's possible that saving a couple of bytes in the source code would have been a con...

PeterJ wrote: ↑Mon May 10, 2021 4:00 pm Hello,

Does this instruction work in the following manner?

Say 16384 contained AA, and 16385 contained 2A

Then LD HL,(16384) would mean HL contained 2AAA

Thanks

Yes.

PeterJ wrote: ↑Fri May 07, 2021 2:21 pm I would love to see the ATM more popular outside of Russia.

Maybe we could start a rumour that it actually does dispense bank notes.

The lack of BIT A,r has always been a bit annoying, and I now see that my self modifying code solution to build the SET, BIT or RES command to order, well it's slower than doing up to 7 RLCA followed by an AND or OR instruction , as well as being harder to follow on any Assembler / Debugger. What i...