Search found 124 matches
- Tue Apr 30, 2024 3:26 pm
- Forum: Programming
- Topic: problems with sjasm
- Replies: 4
- Views: 293
Re: problems with sjasm
I think it's because those files are just the functions to draw vectors and output to the screen. Currently, because you have the output.txt first that gets compiled to the first address you org'd at and that clears the screen to black and then returns. You need some code to call those functions in ...
- Tue Apr 30, 2024 1:34 pm
- Forum: Programming
- Topic: bug in z80 library routines website code?
- Replies: 2
- Views: 125
Re: bug in z80 library routines website code?
It's a macro, from this file https://github.com/breakintoprogram/lib ... macros.z80
- Mon Apr 08, 2024 1:49 pm
- Forum: Games/Software
- Topic: First tape/games you got with your ZX Spectrum
- Replies: 37
- Views: 875
Re: First tape/games you got with your ZX Spectrum
I had two games with my speccy. Mikrogen Space Zombies and I forget the other. Space Zombies didn't even work correctly, the ship would move left by itself randomly.
- Sat Apr 06, 2024 8:56 am
- Forum: Programming
- Topic: Game of Life sizecoding contest
- Replies: 36
- Views: 2471
Re: Game of Life sizecoding contest
Congratulations Tom.
I'm looking forward to seeing how you and dr beep got your code size so low.
I'm looking forward to seeing how you and dr beep got your code size so low.
- Fri Apr 05, 2024 8:14 am
- Forum: Programming
- Topic: Euclidean dist/Sqrt/Multiplication routines 16bit
- Replies: 38
- Views: 1045
Re: Euclidean dist/Sqrt/Multiplication routines 16bit
That may be some kind of Newton Raphson approximation I guess? I've not seen that before and some info about it would be good, to see where the worst case approximations occur. EDIT: Probably a Taylor Series approx instead? Probably needs an else though maybe largest + (smallest>>1) - (smallest>>3)...
- Wed Apr 03, 2024 10:40 pm
- Forum: Programming
- Topic: Euclidean dist/Sqrt/Multiplication routines 16bit
- Replies: 38
- Views: 1045
Re: Euclidean dist/Sqrt/Multiplication routines 16bit
A hacky way of getting this distance between two 2d points is this determine largest and smallest values from x,y length = largest + (smallest>>1) gives a worst case 12% error if smallest >= (largest>>3) then length = largest + (smallest>>1) - (largest>>3) gives worst case ~6% error but mostly <2%
- Wed Apr 03, 2024 5:43 pm
- Forum: Programming
- Topic: Game of Life sizecoding contest
- Replies: 36
- Views: 2471
Re: Game of Life sizecoding contest
Thanks Dr Beep, I'll send it through tonight.
- Wed Apr 03, 2024 5:42 pm
- Forum: Programming
- Topic: Hull-Dobell theorem for procedural generation/screen fades etc.
- Replies: 21
- Views: 779
Re: Hull-Dobell theorem for procedural generation/screen fades etc.
Yeah, should be element = (element >> 1) ^ mask; I guess their typewriters didn't have the xor symbol
I've also realised there's more than the three pages I originally photocopied in the full article.
I've also realised there's more than the three pages I originally photocopied in the full article.
- Sat Mar 30, 2024 11:52 am
- Forum: Programming
- Topic: Hull-Dobell theorem for procedural generation/screen fades etc.
- Replies: 21
- Views: 779
Re: Hull-Dobell theorem for procedural generation/screen fades etc.
I love the ones that look like liquid falling down the screen.ParadigmShifter wrote: ↑Sat Mar 30, 2024 9:05 am Yeah. Spin always hangs after recording a GIF so consider yourself lucky
I only remembered to whack up the emulator speed to 500% after a bit... BASIC sucks etc.
- Sat Mar 30, 2024 10:14 am
- Forum: Programming
- Topic: Hull-Dobell theorem for procedural generation/screen fades etc.
- Replies: 21
- Views: 779
Re: Hull-Dobell theorem for procedural generation/screen fades etc.
I've had this tatty old photocopy of an old Dr Dobbs article for decades which had a really nice way of doing digital dissolves. I found an online copy of it here https://archive.org/details/1986-11-dr-dobbs-journal/page/48/mode/2up It's the Galois LFSR which is on the wikipedia page in the WOS thre...
- Mon Mar 25, 2024 9:53 pm
- Forum: Hardware
- Topic: Harlequin - different versions?
- Replies: 5
- Views: 982
Re: Harlequin - different versions?
I'm no expert, but just looking at the pictures of the board on Bytedelight and the Github page above, it looks like the Byte delight has composite out and a video out while the github one has just video out and a kempston joystick port (from reading the features) I'm going to build a 128K from Byte...
- Mon Mar 18, 2024 9:09 am
- Forum: Programming
- Topic: what would this be equivilent to in assembler?
- Replies: 33
- Views: 1062
Re: what would this be equivilent to in assembler?
As ParadigmShifter said, you're jumping too far ahead if the first key isn't pressed. I think you would find it easier if you moved the three parts of your code into seperate functions. Like below. Then when you add IncreaseY and DecreaseY it will be simple to understand the flow of your code. ; ; R...
- Fri Mar 15, 2024 6:32 pm
- Forum: Programming
- Topic: With Machine Code how much memory to leave basic
- Replies: 7
- Views: 610
Re: With Machine Code how much memory to leave basic
I tend to use 24576/$6000. If you aren't using rom routines or anything that needs the sysvars I guess you could use that memory for buffers once the game has loaded.
- Thu Mar 14, 2024 8:23 am
- Forum: Sinclair Miscellaneous
- Topic: That thing with the blue and magenta ladders (OUT)
- Replies: 39
- Views: 1454
Re: That thing with the blue and magenta ladders (OUT)
It looks like a stack crash, some code got caught in an infinite loop and is PUSHing the same six bytes onto the stack over and over.
- Thu Feb 22, 2024 1:26 pm
- Forum: Games/Software
- Topic: What on earth is Ball Driver?!?
- Replies: 13
- Views: 454
Re: What on earth is Ball Driver?!?
It's here on ebay, If it's not in the database might be worth buying. https://www.ebay.co.uk/itm/175767531437?itmmeta=01HQ8FVF6AM35HGTRJZ5MTS7Y5&hash=item28ec8fafad:g:GnAAAOSwHNpkDOrc&itmprp=enc%3AAQAIAAAA4PuO1E95ylXW9mUtzE2QsCkiq4JZHIcXzAjDUcT9lFf7l4%2FlsfXDMVGKQaACfa0kjSLxaxiYIBoOLoWOu0D%2...
- Thu Feb 22, 2024 1:17 pm
- Forum: Games/Software
- Topic: What on earth is Ball Driver?!?
- Replies: 13
- Views: 454
- Tue Feb 20, 2024 11:18 am
- Forum: Hardware
- Topic: Incorrect voltages on Spectrum 3b
- Replies: 35
- Views: 1218
Re: Incorrect voltages on Spectrum 3b
ULA A14-15 are the same as the Z80, ~0v
ULA A0-A6 are ~3.6v
ULA A0-A6 are ~3.6v
- Tue Feb 20, 2024 10:19 am
- Forum: Hardware
- Topic: Incorrect voltages on Spectrum 3b
- Replies: 35
- Views: 1218
Re: Incorrect voltages on Spectrum 3b
Thanks for the checklist. Checked all those voltages and currents and they match. 0v was about 0.2v but that's probably fine. Without the Z80 and ULA, I measured the V on the A0-A15 and D0-D7. A lines were all 0v on the Z80 and ~3.6v on the ULA. All the D lines were 4.9v. The KB lines on the ULA wer...
- Mon Feb 19, 2024 9:25 pm
- Forum: Hardware
- Topic: Incorrect voltages on Spectrum 3b
- Replies: 35
- Views: 1218
Re: Incorrect voltages on Spectrum 3b
If none of this finds the problem, with ULA, Z80 and TR3 still removed, power up the board and measure the voltages at all three of the transistors terminals, ULA pin 32 and Z80 pin 6, Then, switch to the 200mA current range on your multimeter. Connect it between the Z80 pin 6 and the transistor em...
- Fri Feb 16, 2024 5:35 pm
- Forum: Other Retro Stuff
- Topic: Did actual game code get bigger as game machines evolved? (Excluding graphics and audio)
- Replies: 19
- Views: 1182
Re: Did actual game code get bigger as game machines evolved? (Excluding graphics and audio)
16bit code uses two bytes per instruction (minimum) compared to one byte in 8bit, so code size would increase just for that reason. Additionally 16bit games have more complicated gameplay logic and resource & memory management compared to simpler 8bit games and all that takes more code.
- Mon Feb 12, 2024 6:57 pm
- Forum: Programming
- Topic: Poke to hide "Program:, Bytes:" tape loading prompts
- Replies: 38
- Views: 1031
Re: Poke to hide "Program:, Bytes:" tape loading prompts
I wonder if you could poke the two bytes to jump off to a function that ignores the print but repairs the sysvars for when the program runs. Probably overkill
- Mon Feb 12, 2024 6:48 pm
- Forum: Programming
- Topic: Poke to hide "Program:, Bytes:" tape loading prompts
- Replies: 38
- Views: 1031
Re: Poke to hide "Program:, Bytes:" tape loading prompts
Just looking at the Rom disassembly, it's doing just that. Points to a Ret rather than the PRINT_OUT function.ParadigmShifter wrote: ↑Mon Feb 12, 2024 6:40 pm
Hmm its replacing the low byte of a function pointer with 111... maybe that just points to a RET instruction in the ROM afterwards or something
- Mon Feb 12, 2024 6:25 pm
- Forum: Programming
- Topic: Poke to hide "Program:, Bytes:" tape loading prompts
- Replies: 38
- Views: 1031
Re: Poke to hide "Program:, Bytes:" tape loading prompts
10 CLEAR 24575: LOAD ""SCREEN$: POKE 23739,111: LOAD ""CODE: RANDOMIZE USR 24576
I searched for this recently and it took ages to find. I haven't tried it though, just pasted the code at the bottom of my source for when I need it.
I searched for this recently and it took ages to find. I haven't tried it though, just pasted the code at the bottom of my source for when I need it.
- Mon Feb 12, 2024 2:19 pm
- Forum: Programming
- Topic: Game of Life sizecoding contest
- Replies: 36
- Views: 2471
Re: Game of Life sizecoding contest
Is the competition still open? I forgot to send in my entry.
- Tue Jan 30, 2024 4:55 pm
- Forum: Programming
- Topic: Z80 assembly development environment recommendations
- Replies: 31
- Views: 1324
Re: Z80 assembly development environment recommendations
I'm using VSCode+Dezog too. The tutorials on the Dezog github page got me started.