Search found 673 matches

by dfzx
Sun Dec 17, 2023 9:27 pm
Forum: Programming
Topic: HiSoft C programmers?
Replies: 38
Views: 947

Re: HiSoft C programmers?

_dw wrote: Sun Dec 17, 2023 8:34 pm I'm not good enough for C.
Well that's fair enough. But then it's not really fair that you criticise the language when you readily admit that the language isn't the actual problem. Unjustified and inaccurate criticism just puts potential users off.
by dfzx
Sun Dec 17, 2023 9:12 pm
Forum: Programming
Topic: HiSoft C programmers?
Replies: 38
Views: 947

Re: HiSoft C programmers?

Selling variables via the stack even if recursion is not used is simply expensive, so then I try to make various exceptions to selling via registers, but this can only work if the function no longer calls another non-recursive function. Then the variable must be cleaned up on the stack or in memory...
by dfzx
Sun Dec 17, 2023 2:50 pm
Forum: Programming
Topic: HiSoft C programmers?
Replies: 38
Views: 947

Re: HiSoft C programmers?

ketmar wrote: Sun Dec 17, 2023 2:13 pm that's why. i literally replied to OPs question in full with my very first message here.
Oh I see. Your opinion on modern Z80 C is based on your experience with HiSoft C for the ZX Spectrum from 1984. Yes, that explains quite a lot.
by dfzx
Sun Dec 17, 2023 2:02 pm
Forum: Programming
Topic: HiSoft C programmers?
Replies: 38
Views: 947

Re: HiSoft C programmers?

it is just an example of complex app. ok, let's take another one: scriptable text editor, for example. again, i can fit it into 16 kb (prolly even less), with fully-featured compiled language inside. but i know, this, again, is not the task we're doing today. actually, any more-or-less complex task...
by dfzx
Sun Dec 17, 2023 1:03 pm
Forum: Programming
Topic: HiSoft C programmers?
Replies: 38
Views: 947

Re: HiSoft C programmers?

but try to write something else and complex with Z80 C — like, for example… native C compiler — and you'll see how useless Z80 C is. ;-) No you won't. Z80 C isn't useless. Lots of good software has been written in it. Z80 C is excellent for a whole bunch of tasks. and ZX Forth compiler can be about...
by dfzx
Sun Dec 17, 2023 11:06 am
Forum: Programming
Topic: HiSoft C programmers?
Replies: 38
Views: 947

Re: HiSoft C programmers?

If anyone so much as mentions C on the Spectrum Computing forums our little band of C-haters will immediately pop up and pronounce what a terrible language it is, how badly it works on the Z80, how recursion is a problem and how anyone interested in C should definitely be learning Forth instead. Tak...
by dfzx
Fri Dec 15, 2023 10:50 am
Forum: ZX Spectrum Next
Topic: UK units dispatched!!!
Replies: 26
Views: 1417

Re: UK units dispatched!!!

I'm currently counting 21 of them for sale on ebay, all inside 24 hours. Hard to see those rather optimistic £700 - £1,000 buy-it-now price tags being met much longer. Which is good. I appreciate people ordered their machines 3 years ago and many people's circumstances have changed, but it still rat...
by dfzx
Fri Dec 08, 2023 7:10 pm
Forum: Emulators
Topic: Different ROM in old version of fuse
Replies: 5
Views: 273

Re: Different ROM in old version of fuse

Why was it used for the fuse emulator? That's the ROM bundled with the Debian FUSE package (Ubuntu is based on Debian) because Debian is rather hot on only using freely licenced code and material. The 1982 ROM isn't distributed under any free licence so Debian needed an alternative. If you don't in...
by dfzx
Thu Dec 07, 2023 8:58 am
Forum: Website
Topic: How I find [CENSORED] game
Replies: 56
Views: 2527

Re: How I find [CENSORED] game

I've added the following to the home page: Please note that you can't search for X-rated via this site. They are not omitted from ZXDB though, so we suggest you use a site like https://zxinfo.dk/ to search for such titles. Actually, what you've added to the home page says: Please note that you can'...
by dfzx
Sat Dec 02, 2023 10:20 am
Forum: Games/Software
Topic: Physics puzzles games
Replies: 23
Views: 534

Re: Physics puzzles games

What about flight simulators? We don't discuss those much on SC, and I've never come across a disassembly of one. But surely they employ the laws of physics, at least to some extent?
by dfzx
Sat Dec 02, 2023 10:16 am
Forum: Games/Software
Topic: Physics puzzles games
Replies: 23
Views: 534

Re: Physics puzzles games

Jbizzel wrote: Fri Dec 01, 2023 11:48 pm Gravity my boy.
But MM doesn't use gravity. The jump is just an up-and-down animation. The falling is just incrementing Y by a set amount. I suspect the vast majority of platformers don't use any rules of physics or any sort of gravity equation.
by dfzx
Tue Nov 28, 2023 3:40 pm
Forum: Games/Software
Topic: Physics puzzles games
Replies: 23
Views: 534

Re: Physics puzzles games

berarma wrote: Tue Nov 28, 2023 3:31 pm ...there aren't many games involving physics in a meaningful way.
I loved Sagittarian Pinball BITD. There was also a game of pool I really liked, I think it was this one, but 40 years might have blurred my memory somewhat. But you asked for puzzle games, and neither are.
by dfzx
Wed Nov 22, 2023 9:55 am
Forum: Hardware
Topic: Can a misaligned 12V kill /M1?
Replies: 2
Views: 129

Can a misaligned 12V kill /M1?

The problem with some some Spectrums' Z80's /M1 lines not working is well known, but I recently noticed this blog post from Tynemouh Software: http://blog.tynemouthsoftware.co.uk/2017/07/z80-m1-signals.html He says: "However, if you look at the ZX Spectrum edge connector, M1 is right next to th...
by dfzx
Sun Nov 12, 2023 7:04 pm
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

According to the DRAM waveform, data are supposed to be available on lowering /CAS. No, that wouldn't make any sense. /CAS goes low when the second part of the address (the column address) is on the 7-bit address bus. The memory then has a certain amount of time to fetch the data byte and put it on...
by dfzx
Sun Nov 12, 2023 12:15 pm
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

I don’t know when the ULA samples the data. But at some point it does. That, fundamentally, is the problem. We don't (and can't) know when the ULA samples the data from the bus, which means we need to ensure the data is there for enough time, and that introduces guesswork. Without the ability to te...
by dfzx
Sun Nov 12, 2023 12:01 pm
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

Can you tell if those sparkles are read or write problem? If they were read problem I'd expect sparkles move, while if they were write problem, I'd expect sparkles being fixed. There are never write related problems. The ULA doesn't write to RAM. The Z80 does all the writes, and the Z80 is much mor...
by dfzx
Sun Nov 12, 2023 9:42 am
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

So, do Retroleum and ZXzigg ram modules use four layers board? The Retroleum board is definitely 4 layer - I have one and have checked. I don't know about the ZX Zigg board, I've never seen one. Judging by that copper pour on the underside, I would guess not. No one is saying that this memory board...
by dfzx
Sat Nov 11, 2023 6:40 pm
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

Pygmalion wrote: Sat Nov 11, 2023 1:36 pm By the way, retroleum sells the DRAM replacement again (https://www.retroleum.co.uk/zx-spectrum-chips), but he uses only three chips, so I think he probably uses the same (unreliable) design.
It's not an unreliable design. It works perfectly well as a 4 layer board.
by dfzx
Sat Nov 11, 2023 1:07 pm
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

Hence it will switch its outputs off (to high resistance mode) as soon as either the /CE (/CS) or /OE pins goes to the inactive state (which is high). Yes, that's the gist of it. The SRAM's /OE is permanently on, and /CE is switched by the CAS signal, so in theory when the ULA has read the data and...
by dfzx
Sat Nov 11, 2023 11:44 am
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

I do not understand what the real advantage of the four-layer design is. Will the DRAM retain the output data longer as a result? I doubt it. My uneducated guess is that a two-layer design should be just as good as any other. The 4 layer design provides a ground plane and a power plane positioned i...
by dfzx
Fri Nov 10, 2023 5:28 pm
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

i have been trying to understand the actual original timing from the original DRAM a bit better complicated by the page mode for ULA reads. i have been reading again "the ULA" book by chris smith.... The problem as I understand it isn't the ULA as such, it's the SRAM. The RAS/CAS/latching...
by dfzx
Fri Nov 10, 2023 11:01 am
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

In terms of going from a four layer board to a two layer board, the things that may make a significant difference are the width and routing of the 0V/GND and +5V/VCC tracks. The inner layers on my original 4 layer board carried a ground plane and a 5V plane. Mark's (the other Mark's) re-layout has ...
by dfzx
Fri Nov 10, 2023 8:46 am
Forum: Hardware
Topic: New open lower RAM module design (photoessay)
Replies: 98
Views: 2734

Re: New open lower RAM module design (photoessay)

I also have all the necessary chips, but now I have to wait until mark8bit's design is tested. Ordering the PCB just costs too much (board $2, shipping $7) so it's just too expensive for me to just test it. What price point are you aiming for? You can't optimise away the $7 shipping, so the $2 fabr...
by dfzx
Thu Nov 09, 2023 12:09 pm
Forum: Hardware
Topic: Speccy 48k issue 3b: Red and black screen
Replies: 97
Views: 1955

Re: Speccy 48k issue 3b: Red and black screen

Thank you once more @1024MAK for another wonderfully informative post. :)
by dfzx
Thu Nov 09, 2023 9:43 am
Forum: Hardware
Topic: Speccy 48k issue 3b: Red and black screen
Replies: 97
Views: 1955

Re: Speccy 48k issue 3b: Red and black screen

A couple of left over questions, in the spirit of completing the record: Out of curiosity, I wonder, how can you tell from the readings that the ULA and IC3 are faulty? Clearly Mark was right, but how did he know? The socket on the board is also a stamped pin type, but it’s no good for the type of p...