Spectrum Computing

I noticed there's a slight graphical glitch in Galaxian arcade... don't know if it happens all the time or only some of the time. I managed to pause the youtube video on the exact frame one of the aliens started swooping and it disappeared for a frame. So it looks like there may be a 1 frame gap bet...

I can think of lots of reasons why games would have wildly different code vs. data distributions, and therefore averaging them may give a distribution with multiple peaks. https://en.wikipedia.org/wiki/Multimodal_distribution Some reasons off the top of my head: * hardly any graphics (puzzle games s...

Well collect a load of data (you probably want to normalise it to take into account different program and data sizes i.e. make it in the range 0-1 where 0 = all data no code, 1 = all code no data) and run it through something like this which will estimate the probability density function for you htt...

Ok well programmers don't like being limited in how much of the main memory they can use which is 1 thing the N64 got right I think (never programmed for that though). If you use modern CPU you will have enough memory anyway to not need to worry about it. But maybe you know better than all these pro...

I agree.

You can probably also try the retro computing museum (in Leicester I think?) or one of the retro computing Youtube peeps they would probably take it off your hands.

There'll be a "choose ROM" option in the emulator. (Some emulators ship with a replacement ROM instead of the 48K one - I think those are Linux open source ones which don't want to include the now copyright Amstrad ROMs (which they have given permission to distribute) since it is not open ...

You don't want to set a limit on code size anyway, just have all the memory available for whatever purpose you need? Anything that does set a limit (e.g. PS1 had 2MB main memory, 1K (lol) very fast cache* memory, 1MB VRAM, 512K (not enough) sound RAM IIRC) also had mass storage devices so you could ...

As long as it is called Ghosts N' Bummedinthegoblins I will be happy.



EDIT: my sizeof(ATTRIBS) post congrats me

You can also use 16 bytes for a mirror table if you want and mirror each nybble separately if you start running out of memory too. That's a bit slower but you can do it without shifting if you store the mirrored nybble data in the both the high and low nybbles so you don't need to shift, just mask. ...

Each is as long as a piece of string. Why not pick some games from this list https://skoolkit.ca/links/ and look at the disassembly e.g. here's Luny's disassembly of Marsport which has code flagged in green, data flagged in pink http://luny.co.uk/gargoyle/marsport/maps/all.html Usually you can chang...

The main thing was that my belief that ASM == BIN simply does not apply 100%. On the Z80 it is though which makes it easier to understand. Obviously macros don't count ;) Only things that can affect the timing are interrupts and contention I think? More modern CPUs got way too complicated to unders...

You can just usually add up the TStates though and work out which one is faster. Of course clever optimisations exist but those are based on mathematical identities and stuff. Register allocation is important too obvs since the Z80 is not very orthogonal in terms of instructions (e.g. you can ld (hl...

That's more to do with coprocessors and pipelining and stuff though which the Z80 does not do. Nowadays with pipelining, branch prediction, caches and coprocessors it's way too hard to translate instructions into execution time and the compiler is usually better than humans at it anyway. None of tha...

Lol watching the Knockout video that has to be the worst rendition of a well known tune (eye of the tiger) I have ever heard.

I suppose Survivor can't sue though since it was so terrible it would look bad on them

I don't think snapshot format will affect anything unless you do weird stuff like changing interrupt modes a lot or are trying to accurately simulate peripherals for say timing purposes. Don't worry about it. Probably go with what was recommended (.z80). EDIT: I do detect a slight case of the "...

Well it's either cricket >> tennis >> baseball I guess? A >> B means "A is much greater than B" of course. Could be golf though but it looks like a baseball or a tennis ball. Cricket ball would probably be filled in pixels since they didn't use white balls for 1 day cricket in the 80s?

.tzx files are great also you can record some gameplay and play it back... I often think I have spotted bugs and when looking at the playback I can check whether they were actually bugs or if I was wrong about it being a bug. And if it is a bug it's not that* hard to step into the debugger just befo...

I was reminded of this thread when I watched this which points out some pitfalls of that algorithm (which I was aware of but neglected to mention of course) for testing whether you are inside a shape for which it sounds like took a long long time to debug lol. It's more complicated since it's testin...

I'm sure it will be easy to hack though if you run it in an emulator. You either want to find out where the initial number of moves is read from and change the values or else where it checks whether the moves has exceeded the limit (every time you move I guess - so start out looking for routines rea...

Yup Moon Cresta was excellent too but I'd put it in the later releases category than the earlier decent 16K ones. Penetrator was an excellent Scramble clone too and also early. I think there was a good version of Moon Patrol (or Buggy or something) the one with the craters too. (Let's face it Lunar ...

Yup Amen to that. Do as little as possible in the emulator except test and debug (debugging is only really possible if you program in ASM or are very familiar with the tools you use to produce the program - which usually means you wrote the tool yourself in ASM). Debugging ZX BASIC using a debugger ...

It's a press 1, 2, 3 game like whackamole really based on an arcade game.

It's fun though.

Yup that's correct I was surprised when my random choice had Morkin (regular poster here) and Rorthron (not so regular poster here I think) as the authors

I thought Morkin may have given it away too easily at least he played ball though and kept mum

Either should be fine I guess? If what you are using just outputs raw binary file though (so an assembler, or a compiled language that outputs pure machine code output) I just save it as a .bin file and use the load binary file of the emulator to load it at the correct address. So I assemble my sour...

Well you know what they say about clues, some are deeply hidden and some are hidden in plain sight