Spectrum Computing

It is funny that it made you annoyed yet you had to wait until 3AM Wednesday morning to make your point though :) It's only a quiz after all. Let's get quizzical, quizzical, let's get quizzical. Olivia! I thought you were so nice and innocent (until last 5 minutes of Grease anyway), then I saw this ...

So basically you are going to have to hack the code to do the loading of the next part of the tape from BASIC via microdrive instead, skip the machine code bit that loads something and call the proper entry point (after the machine code loading has finished). If it does any checks that the memory ha...

The numbers don't look obfuscated after I tried a MERGE "" with the tap file anyway. EDIT: But it does then load more code after the PRINT USR 24576, so it calls a tape loading routine from the machine code... probably be difficult to make it not do that I think? I tested that by putting a...

Those POKES make it crash if you break into the program while it is loading. Maybe they have also obfuscated the code by poking different values into the actual numerical value shown in the listing (numbers in BASIC are stored as ASCII for printing by LIST but then the actual value is stored afterwa...

You're only outputting a .lst file? I tried that on my (speccy) code, this is the kind of thing it produces # file opened: sheet.asm 1 0000 ; sjasmplus.exe --sym=out.sym --syntax=f --raw=out.bin sheet.asm 2 0000 3 0000 DEVICE ZXSPECTRUM48 4 0000 5 0000 TIMING EQU 1 6 0000 7 0000 ORGADDR EQU #8000 8 ...

It's just a challenge. (Obviously challenges can be fun too). Obviously if you care about code size that much you need to program in assembly (or Ketmar will be along soon to mention Forth which also has a very compact code footprint), as soon as you get into higher level languages/compilation (mayb...

They are 12 apart in Y direction I might try 10 instead. That probably won't fit well with the attribs though. Main thing is getting the bottom 3 rows to be same colour I guess and the top one to be mainly yellow. I'll probably do a stripy attribs thing to see what might look best. I can't squash th...

9 looks like Level9

Ok my attempt at a sheet shoot em up is underway, day 1 progress. https://i.postimg.cc/kMt7TJkY/sheettest.png Red border is how long it takes to redraw everything. * Drawing each row at a time instead of each column. I think it will be fast enough to manage it. I'm going to need to draw 1 extra alie...

It's just a reserved data block. Might not even need to load it unless there is an existing template it just modifies (like changes PUSH and POP instructions).

I suppose once you start executing it it's technically code though.

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 "...