 Previous Messages |
Posted By
BSZ
on 2024-09-14
14:49:10
|  Re: 3d shooter for the +4
Watching the video I can see some pitfalls with the possible plus/4 port, but I'd be curious to see the end result! 
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Posted By
Csabo
on 2024-09-14
14:32:49
| Re: 3d shooter for the +4
The topic is a little misleading though When I first saw it, I was like "Really?! Let me see!" - then I realized you mean someone could potentially convert this. You could say I was baited to click the topic 
IMHO I could convert this game during a week if I had a proper motivation.
Whoa, that would be awesome! Come on guys, who has got some extra motivation laying around? 
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Posted By
Litwr
on 2024-09-14
08:51:03
| Re: 3d shooter for the +4
This machine assembler is theoretically very good: 7 GPR, 16 bit ops, orthogonality, good instructions. But practically all PDP-11 CPUs are very inefficient. The best of them like the J11 use 8 ticks for one memory access! The BK shares RAM for the CPU and video so its CPU needs 12 ticks to a RAM access. The 6502 needs only 1 ticks for this. The Z80 needs 3 ticks. For 16-bit ops we get 6 ticks per byte on the BK, but if you work with single bytes you need all the 12 ticks for every byte! The BK CPU works at 3 MHz.
I agree that the BK has generally better code density but the +4 has much more RAM than the BK. The BK has only 32 KB of RAM and 16 KB of RAM are used for the video.
It is quiet easy to convert the PDP-11 instructions into the 6502 equivalent code. IMHO I could convert this game during a week if I had a proper motivation. It is easier for the PAL variant of the +4, we can use 256x256 4 color screen in this case.
You can find more details in Wikipedia.
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Posted By
gerliczer
on 2024-09-14
04:21:42
| Re: 3d shooter for the +4
What kind of computer is that ВК0010? What I could glean from Wikipedia suggest a 16-bit CISC machine. Those usually have relatively high code density, therefore the code being only 8 kB probably translates not quite favourably to 6502 based machines.
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Posted By
Litwr
on 2024-09-13
16:19:57
| 3d shooter for the +4
A new superfast 3D shooter has just been released for the BK0010 platform - youtube - this computer is not faster than our +4 and it has only 16 KB RAM and has to handle 256x256 4 color graphics. The code size is 8 KB, the sources are available.
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