Sikor Posted February 20, 2007 Share Posted February 20, 2007 (edited) In Poland two person make two different emulators of ZX Spectrum for Atari XL/XE. For me it is great news - maybe it will be very slowly thing, but - for example - in text-adventure games is no problem. You can search this topic http://atariarea.krap.pl/forum/viewtopic.php?id=4772 at atariarea.krap.pl (polish only - sorry, guys ). What is made now: Draco030 make USE - Unusable Spectrum Emulator - a fully emulator of ZX Spectrum. Now it is have ZX-Basic implements and working about 5-6% of speed on original computer. XXL make other thing: pseudo-emulator, which is not fully emulate ZX, but interpretate and running Spectrum programs. Some of this working now with speed from 5 up to 10% of originally ZX. What do you think about this two projects...? Unbelivable for me Edited February 20, 2007 by Sikor Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 20, 2007 Share Posted February 20, 2007 Draco030 make USE - Unusable Spectrum Emulator - a fully emulator of ZX Spectrum. Now it is have ZX-Basic implements and working about 5-6% of speed on original computer. Nope, my emulator is not called "USE", this is the name invented by dely and adopted by XXL for his program. The speed figures are a bit outdated too (it was so about a week ago). Quote Link to comment Share on other sites More sharing options...
+Larry Posted February 20, 2007 Share Posted February 20, 2007 Draco030 make USE - Unusable Spectrum Emulator - a fully emulator of ZX Spectrum. Now it is have ZX-Basic implements and working about 5-6% of speed on original computer. Nope, my emulator is not called "USE", this is the name invented by dely and adopted by XXL for his program. The speed figures are a bit outdated too (it was so about a week ago). So perhaps with a few improvements and a 65816 accelerator... -Larry Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 20, 2007 Share Posted February 20, 2007 So perhaps with a few improvements and a 65816 accelerator... Improvements are being made all the time (this outdates Sikor's figres ) - and well, with the accelerator the program will certainly be faster. However, a version written specially for 65C816 will be yet faster, on standard 6502 and 130XE there's some overhead one can avoid on the better machine. Quote Link to comment Share on other sites More sharing options...
www.atarimania.com Posted February 20, 2007 Share Posted February 20, 2007 That's fascinating! Will it support both 16K and 48K versions of the Spectrum? -- Atari Frog http://www.atarimania.com Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 20, 2007 Share Posted February 20, 2007 (edited) So far the emulated machine is ZX Spectrum 48k (this is why it requires 130XE: it needs 48k for ZX RAM and 16k for ZX ROM). Is there any need to limit the RAM to 16k? I can add such an option, of course... Edited February 20, 2007 by drac030 Quote Link to comment Share on other sites More sharing options...
www.atarimania.com Posted February 20, 2007 Share Posted February 20, 2007 So far the emulated machine is ZX Spectrum 48k (this is why it requires 130XE: it needs 48k for ZX RAM and 16k for ZX ROM). Is there any need to limit the RAM to 16k? I can add such an option, of course... It's even more amazing that you can emulate the 48K version so I thought I'd ask Not sure if all 16K programs run on 48K systems... Do you think 16K emulation would work on a stock 800XL? Even ZX-81 emulation would be great fun! -- Atari Frog http://www.atarimania.com Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 20, 2007 Share Posted February 20, 2007 Do you think 16K emulation would work on a stock 800XL? I think it would... if the entire emulator code fits in about 22-25k, it is possible. Even ZX-81 emulation would be great fun! I may be wrong, but I think that ZX-81 is more difficult to emulate on Atari, than the ZX Spectrum Quote Link to comment Share on other sites More sharing options...
www.atarimania.com Posted February 20, 2007 Share Posted February 20, 2007 I think it would... if the entire emulator code fits in about 22-25k, it is possible. Does the 48K version of the Spectrum just have more memory and better sound or are there other differences? How fast do you think the emulator will be in the end? I may be wrong, but I think that ZX-81 is more difficult to emulate on Atari, than the ZX Spectrum Really? Why? -- Atari Frog http://www.atarimania.com Quote Link to comment Share on other sites More sharing options...
Gury Posted February 20, 2007 Share Posted February 20, 2007 ZX Spectrum (16K and 48K) had the same sound beeper with 1 voice and 10 octaves, ZX SPECTRUM 128 and it's successors made by Amstrad used Yamaha AY-3-8912 (3 channels with 7 octaves). Quote Link to comment Share on other sites More sharing options...
Ross PK Posted February 20, 2007 Share Posted February 20, 2007 I wouldn't have thought this possible, it's kinda like a Gamecube emulating a Dreamcast. Quote Link to comment Share on other sites More sharing options...
Pengwin Posted February 20, 2007 Share Posted February 20, 2007 Not sure if all 16K programs run on 48K systems... Do you think 16K emulation would work on a stock 800XL? Even ZX-81 emulation would be great fun! To my knowledge, all 16K spectrum programs will work on the 48K machines. I would love to see a 16K emulator on a stock 800XL Quote Link to comment Share on other sites More sharing options...
Pengwin Posted February 20, 2007 Share Posted February 20, 2007 Does the 48K version of the Spectrum just have more memory and better sound or are there other differences? How fast do you think the emulator will be in the end? I think the only difference between the two was the memory, although to be 100% sure, I'd have to check. Quote Link to comment Share on other sites More sharing options...
deathtrappomegranate Posted February 20, 2007 Share Posted February 20, 2007 The 16K and 48K "rubber-key" Spectrums differed only in the amount of RAM. Later Speccy models had a new sound chip, though, as well as ROM revisions, better keyboards and built-in storage. Quote Link to comment Share on other sites More sharing options...
Pengwin Posted February 20, 2007 Share Posted February 20, 2007 I've just had this confirmed, the 16K model was exactly the same as the 48K, but with empty sockets, where the 48K had the extra RAM. Quote Link to comment Share on other sites More sharing options...
pps Posted February 20, 2007 Share Posted February 20, 2007 Great work!!! Nice idea to put some other computers into our beloved machine Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted February 20, 2007 Share Posted February 20, 2007 your polish coders are really maniacs.... Quote Link to comment Share on other sites More sharing options...
Allas Posted February 20, 2007 Share Posted February 20, 2007 I think the most difficult technical topic is the multicolored text mode in 8 color that Spectrum computers have. Most of the game works in this mode. But its cool to see a Spectrum emulator in Atari 8-bit. ZX81 its possible to emulate at 100%, because it more slow that Spectrum and only works with 2 colors, not sound. Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 20, 2007 Share Posted February 20, 2007 I may be wrong, but I think that ZX-81 is more difficult to emulate on Atari, than the ZX Spectrum Really? Why? Coz in ZX-81 the Z80 creates the display. ZX81 its possible to emulate at 100%, because it more slow that Spectrum and only works with 2 colors, not sound. Well... go ahead. Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 21, 2007 Share Posted February 21, 2007 How fast do you think the emulator will be in the end? I overlooked that question. Well, it is difficult to say. On standard Atari, the 48k Spectrum emulation certainly is not a speed daemon. I expect however, that a version written specially for the 65C816 accelerator may be actually usable as a true emulator. This would obviously depend on the accelerator clock speed, and again, it is rather difficult to estimate the final result, but from the experience I got writing the 6502 version of the emulator, and from some draft 65C816 code I did, I now tend to think that at 14 MHz the emulator may be nearly as fast as the ZX Spectrum itself. Quote Link to comment Share on other sites More sharing options...
Tezz Posted February 21, 2007 Share Posted February 21, 2007 (edited) That's very impressive! ... Interested to see where this goes ... Btw. the 65C816 is the 16-bit 6502 version.. does the 65C816 support the full 6502 instruction set? I mean is it backwards compatible if installed? If so, it would be worth upgrading my 130xe from the stock 6502 I would think? Yes or No Tezz EDIT: I've been reading drac030's website http://drac030.krap.pl/en-specyfikacja.php Edited February 21, 2007 by Tezz Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 21, 2007 Share Posted February 21, 2007 Btw. the 65C816 is the 16-bit 6502 version.. does the 65C816 support the full 6502 instruction set? I mean is it backwards compatible if installed? If so, it would be worth upgrading my 130xe from the stock 6502 I would think? Depends, what do you mean for "full 6502 instruction set". The 65C816 certainly has all official 6502 instructions. The only problem may be, if a program uses illegal 6502 instructions - it won't work on 65C816 machine then, because opcodes illegal in stock 6502 are assigned to new instructions in 65C816. From experience, I can say that very few programs actually use illegal 6502 instructions and thus refuse to run on the new processor. This is like 10 games out of 130 I tested, maybe 2 (rather old) demos out of 40 I tested, I don't recall any utility program which would have problems, but I think one or two can be found, probably. Quote Link to comment Share on other sites More sharing options...
JamesD Posted February 21, 2007 Share Posted February 21, 2007 One of the advantages of the 65816 is that you could use the DP register to place page 0 type functions elsewhere. That would let you open up the lower memory map for the speccy so you don't have to translate all the memory addresses. For ROM you mostly need common entry points like their open ROM project has. Quote Link to comment Share on other sites More sharing options...
analmux Posted February 21, 2007 Share Posted February 21, 2007 (edited) From experience, I can say that very few programs actually use illegal 6502 instructions and thus refuse to run on the new processor. This is like 10 games out of 130 I tested, maybe 2 (rather old) demos out of 40 I tested, I don't recall any utility program which would have problems, but I think one or two can be found, probably. (beware: OFFTOPIC) Is there a good reason to use illegal opcodes? Is it possible to make faster code (in some situations) by using them? Edited February 21, 2007 by BRK Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 21, 2007 Share Posted February 21, 2007 Is there a good reason to use illegal opcodes? Is it possible to make faster code (in some situations) by using them? Few can be of some use, yes. But it is not deadly advantageous, as you can see from the percentage of programs actually using them. Moreover, a part is used apparently not to make code faster or shorter, but to make disassembly more difficult. Quote Link to comment Share on other sites More sharing options...
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