Spectrum Computing

I think Jetpack (and other Ultimate games) erase and draw sprite at the same time, line by line. It sounds like horrible idea but sprites usually move just a little bit so this method basically replaces flickering by possible tearing. Well, you can check how it looks on YT yourself. with Jetpack th...

by the way, my first contant with Forth was on ZX. i had… yeah, Abersoft Forth, pirated of course, without any documentation. and i had no idea what that "Forth" was. it was on a cassete with other languages (LISP, HiSoft Pascal, etc.), so it was definitely some language, but… what to type...

ParadigmShifter , the problem is that i want to make everything easy to use. the idea is that you only call "SPR-UPDATE" word with new sprite position and animation frame, and the system will magically do the rest. i don't want the user to think about interrupts, where to insert HALT, and...

also, moving the system to $8000, and removing RAM-DISC will leave about 12KB of RAM free for user code. this is quite a lot (the whole system is ~15KB now, or ~18KB with fullscreen editor). so i will prolly ditch RAM-DISC at all, and implement support for TR-DOS and +3DOS instead. i mean, 'cmon, yo...

i implemented "prepare, then redraw in interrupt handler" engine for 16x16 sprites with run-time shifting… and will throw it away now. ;-) it doesn't worth the efforts. it requires 2KB for buffers, takes a lot of time to prepare buffers, and dog slow even with 13 sprites (this is as much a...

There's always Machine Lightning, which presumably has similar capabilities. While the software is in the archives, the documentation appears to be lost at the moment :cry: thank you! but it still doesn't have a source code (or i am unable to extract it). i mostly need the source to create relocata...

you doesn't switch banks , you are changing address mapping . think of it this way: address $C000 can be mapped to one of several memory banks, and you are selecting to which one. there is no changes in bank order. i.e. $C000 is a "window" you are using to look at a huge RAM, and by OUTing...

oh, i see. Jonathan did exactly what i thought of: simultaneous erasing and drawing after vblank. only AGD doesn't have run-time sprite shifting, so no need for any temp buffers. ok, i will prolly make two versions: with shifts, and without. so 3 sprite engines now, lol: White Lightning like, XOR16 ...

creating flicker-free XOR sprites is surprisingly hard. i wonder how Jonathan Cauldwell did it in AGD. althrough AGD is not shifting sprites, i believe. i created 16x16 blitter with shifting, so i can blit at any x pixel coord, but of course it flickers hard. HALT only helps with 2 sprites or so. an...

added (optional) OR/XOR/AND blitters too. with all blitters included library size is ~1KB.

wrote simple sprite blitter. currently only in overwrite mode, at char positions. tested on White Lightning sprites, lol. the code is not superfast (althroug it is using unrolled LDI loop per sprite line). it would be easy to modify the blitter to allow arbitrary y coords (not restricted to chars), ...

i cached "NEXT" in IX. the code became slightly smaller, and slightly faster. not much, but why not? IX was used for user area pointer, but we don't have a lot of uservars anyway, so it was a waste of register. i wonder if caching TOS in DE will do any good. but this will require rewriting...

Can I try the editor somewhere and is there a documentation ? I wonder how much space a minimal fullscreen editor would take. 2.9 KB is quite a lot, considering line editor can take perhaps one third of space, I guess. latest demos in this topic are compiled with the editor. just type "LOADT 1...

by the way, contented memory sux! Erathosthenes test is ~1.7 seconds faster when the system is uncontended.

but i am not ready to waste 8KB of RAM by moving the system to $8000 yet.

Will this ever be available to use on real speccy or are you concentrating on emulator only? it should work on the real hw, why not. i don't have real machine anymore, though, so any bug reports from reals are welcome! The floating point is a nice useful feature and would say a full doubles extensi...

i really want "ex sp, sp'" instruction. having two stack pointers and 4ts (ok, even 8ts) way to switch between them is something any Forth programmer always deaming of! ;-) (unless we can use any register as stack pointer, of course.)

funny, that's exactly how they are defined:

flange , thank you for your support! yep, "advanced" comparisons are not properly tested yet, thank you. they weren't in the original, and i wrote the code in "blind mode", just to have something there. ;-) as for not popular language… i am using x86 Forth system on daily basis ...

by the way. WIP version to play with: download .TAPs . WARNING! this is NOT final! it should work, but there may (and will) be some bugs. there are 3 .TAP versions, all with demo game. WARNING! demo game works only in 32cols mode. to load demo game, use: "LOADT 1 LOAD" source code will be ...

also, there will be a target cross-compiler which creates "turnkey" apps, omiting all headers, and all unused words. but you'll need x86 GNU/Linux to use it.

nope, "main system size" is total size (bad description, i know ;-). 16 kb with all bells and whistles. can be much smaller if various optional parts are turned off. p.s.: note that even with RAM-DISC you'll have ~13 kb for your code (this is about as much as the original Aberforth had). a...

just4fun, some current system stats. build options: threaded code type: ITC header format: new branch offsets: absolute optimise by: speed print driver: 64 columns CLIT/BLIT: enabled 16-bit mul/div: slow bit shifts: disabled extra block words: disabled editor words: disabled fullscreen editor: enabl...

hm. i decompiled Forth part of White Lightning, and it looks quite interesting. the usual fig model code is intact (of course), along with several standard fig inefficiencies. but the added code looks way more interesting. for exampe: it contains two "AT" implementations, absolutely identi...

fun fact: for some reason White Lightning has around 40 hidden words. they are not linked to any vocabulary, but have valid headers and names (and they are referenced from other, visible words). it looks like that system wasn't cross-compiled from some asm source code, but created in several stages....

ported ROM floating point library from dsForth. for ~1KB of code you'll have full floating point support, backed by ROM calculator. because why not? ;-)

i know, i know, Chuck Moore said that floating point math is for wimps. but hey, i don't have to write my own FP code in asm anyway! ;-)