Spectrum Computing

R-Tape wrote: ↑Wed Jul 01, 2020 8:23 pm

ketmar wrote: ↑Wed Jul 01, 2020 8:09 pm UltraRex. yep, you prolly guessed it right.

What's UltraRex? Is it distinct from RexNext? :shock:

of course! only 3 common letters -- almost completely different thing!

i am pretty sure that we need more Rex games!

UltraRex. yep, you prolly guessed it right. i have little hope to finish even a playable demo, but hey, the topic is not asking about "projects you're going to finish", right? ;-)

p.s.: no, no fancy multicolor there. but i hope to have some other gimmicks.

oh, it's fun to code for Speccy again! while experimenting with various game engine ideas, i fixed several bugs in UrAsm assembler, added label file output from UrAsm and loading labels to ZXEmuT (yeah 8-years-back me did his coding without that), added some colors to ZXEmuT debug window, added tsta...

and i guess we'll eventually have ZXNext titles too, so adding that info to URL is prolly a good idea.

oh, please, can we get those SCUMSOFT games?! i am especially interested in Combat Skool Daze, it sounds like an instant hit!

(somebody, please! Spectrum NEEDS that game!)

i love it! now i finally can share links like this!

why?! please?! *every* 8-bit CPU out there has info about command lengthes in ticks (see p.s.), and one tick has constant time . and machine cycle is not constant time (at least on Z80). there are no fixed number of machine cycles in frame, there are no fixed timing for machine cycle. what exactly a...

Of all the PDFs I have, Z80 is literally the only one that lists T-States alongside cycles, per instruction. http://www.z80.info/z80code.txt you don't need cycles at all here, only t-states. Still, unlike 2D bitmap game with fixed count of sprites and their sizes (hence a fixed, pre-determined scen...

i still don't understand why do you need machine cycles. t-state counting is more precise, it can be easily converted to real/frame timings, any target 8-bit CPU is using t-state counting, and comparing real/frame timings gives much better idea of what the real/relative speeds will be. note that you...

if you aren't creating a precise emulator (contended memory, multicolor, etc.) -- why do you need machine cycles at all? it is as easy to count t-states, and have much more precise result. and even if you want precise emulation, counting t-states is still better.

Heimdall wrote: ↑Sun Jun 28, 2020 5:12 pm I don't know what that guy in eBook was doing with those PUSH/POP/EXX

this is often used for fast screen copying (vitrual screen -> screen$).

it might be slightly unfair for other people doing great things on Speccy, but for me Joffa will always be the most memorable person. i never talked with him, but the games he coded showed me that my little Speccy is capable of much more than flip-screen platformers or very sluggish scrollers. in ma...

(sighs) you're all talking about dealing with ideas you have. thank you, but... i have no ideas! that's the problem. take, for example, Quantum Gardening . i really like it (it is soooo meditative), but i'd never came up with its idea on my own. (whispering) i hoped you guys will tell me the drugs ...

if you're assembling it directly in Spin, you don't have to do `LOAD ""CODE`. this is to load it from tape, but you already put it into memory.

actually, no need to do anything special at all. after assembling it, just do "RANDOMIZE USR 33000", and it should run.

ah... so you want a kind of recompiler? nope, Zymosis is a pure emulator. of course, it can excecute instructions one by one, so you can simply use "step over" `zym_exec_step()`, which does exactly that -- steps over one Z80 instruction. but you have to assemble your Z80 code externally. i...

maybe you can simply take my Zymosis , for example? it is only 50 kb of self-contained source in C (should be standards-compliant), supports any number of CPUs, implements all Z80 instructions including undocumented ones, with precise-enough timings to emulate ZX Spectrum with contended memory. ah, ...

chilledgamer wrote: ↑Wed Jun 24, 2020 1:50 am I understand exactly what you mean about high/low bytes. But actually you made me realise. I don't understand what the line is even doing "ld hl, Message".

in C/C++ syntax, it is:
hl = &Message[0];

the usual "load address to 16-bit internal CPU variable".

oh, there is introductional thread here! so if you're interested, i am from xUSSR. Speccy (actually, Robik ) was my first "really personal" computer. before that, i was at regional computer "club" with MSX computers. of course, i wanted MSX, but there was no way to get it (at lea...

"RET" basically does this: LET addr = peek(SP)+256*peek(SP+1) : LET SP = SP+2 : GOTO addr i.e. it takes the two byte address at (SP), and increments SP by two bytes. so, "ld sp,19074" sets SP to 19074. and "RET" reads address from 19074, and jumps to that read address. ...

azesmbog wrote: ↑Sat Jun 20, 2020 5:09 pm

ketmar wrote: ↑Fri Jun 19, 2020 10:09 pm i'll take the obscure action platformer (DOS) game i love

Spelunky ? :))))

i see what you did here! ;-) and this was the great illustrative example for this topic. i STILL unable to add gameplay there!

Ketmar, doing a not scrolling game with 16 fps (every third) screen is very doable. yeah, but the playsim is quite complex (many monsters, and they should be active all the time, and walk around the whole map, with not-so-trivial logic). of course, i can cheat here if needed (nobody will notice if ...

kolbeck wrote: ↑Fri Jun 19, 2020 8:00 pm Do you recognize the head?

it is amazing how removing attributes turned it into amaterish nightmare drawing.

also, the hand is taken from Fist too, only rotated. it seems that i found a way to create my own loading screens...

added disassembler library to Zymosis. it is based on the same instruction decoding logic as Zymosis itself, so it is only 20 kb of source code, and quite fast. now you can skip importing heavyweight liburasm if you only need to show some disassembly in your debugger. it lives in separate source fil...

di ld hl,22528 ld de,22529 ld bc,767 ld (hl),07 ldir Not sure what the above does. Is it a simple attribute clear routine? yes, exactly. it sets all attributes to "7" (aka "white ink, black paper"). And then it continues... ld hl,40506 ld de,19000 ld bc,76 ldir jp 19028 No idea ...

thank you all once more! reading this thread gave me a nice idea. dunno if it will ever become a game, but hey, it is at least something! i'll take the obscure action platformer (DOS) game i love, and will try to recreate it on Speccy. originally it was at 18.2 FPS, so i can aim at 16 FPS, and maybe...