Acorn Emulation Latest

Details of all previous updates, can be downloaded in a ZIP file - recommended reading.

Thursday 9/4/98

Having just finished a mammoth geography project in less than 2 weeks, yes folks, that's no sleep before 2am for 2 weeks!! it's time to do another update. I'm busy with Computing A level coursework now, until the end of next week, so don't expect any major updates between now and then I'm afraid.

I've managed to borrow a RISC PC 600 temporarily, and have now been able to try out a few more emulators that wouldn't work on my A5000.

• xNES - this runs too slowly on the ARM610 to be playable, but is highly unoptimised at present, and has a few bugs left in it as well. I tried out Strider and Super Mario Bros, and they seemed to work ok with perfectly correct palettes.
• PCengine - the new 100% ARM code implementation is very fast, and it shows. I found I was able to play Bomberman 94 & Parodius, albeit quite slowly but fast enough for me to enjoy a good 1/4 hours game play on each (in emulated time, probably only about 3 mins). With frame skip (which I didn't have in this version) it should run just under full speed on an ARM 610, and pretty well fine on an ARM 710. As far as I could see, there were no graphical glitches, and the palette was perfect, this emulator is looking very promising indeed!
• v2600 - erm yeah, it's an emulator, but as far as I can tell (on an ARM610) it just displays game title screens, it's that slow!

I came across Mike Borcherd's (co-author of Z80em and 6502em) web page, with online manuals for both the spectrum and the BBC emulators. This has quite a lot of in depth knowledge about the two commercial offerings, and if you're thinking of getting either, well worth a look.
http://www.borcherds.demon.co.uk/z80em/
http://www.borcherds.demon.co.uk/6502em/

Some bad news this update is that a group acting on behalf of sega, have ordered the Dump (one of the webs largest Megadrive ROM archives) to remove all Megadrive ROMs :o(

There is a link added to a new BBC documentation project page set up to try and revive all the old documentation, both technical, and user orientated, which would be handy to anyone looking at writing a BBC emulator. Link added to GameBuilders, an attempt being made to write a new homebrew ROM for the NES, looks very promising.

Lazarus the massive amiga software archive for emulators everywhere, is now back online after several months down.
http://www.aqcom.com/lazarus/

Latest news about the megadrive emulator!!!! Those of you on the Acorn Emulation mailing list got a preview of this since I had a small cock up.

Whilst trawling the web, I came across a simulator of the TRS80 BASIC interpreter written in Java. It should work ok with the Java VM on Acorns, though I am not certain of this, please send reports.

The April 1998 edition of Acorn User is now out, with a few emulation mentions. David McEwen's port of fMSX gets a small writeup on page 82 in the 'Game Show' with a mention of how well it plays Donkey Kong. The Acorn Emulation Message Board gets a little plug in the 'YoUR List of sites for ApURL' as part of the comms section on page 15.

Version 0.03 and then 0.04 of my Babe emulator of the Manchester Mark 1 prototype (the world's first stored program computer) have been released with some pretty significant bug fixes, thanks to James Miller. The numeric equivalents of results from the STO instruction are now displayed correctly, no trailing digits are left all over the screen, and the program returns to the desktop neatly rather than making a hell of a mess.

My 6502 core is coming along nicely now, and although delayed a fair bit because of coursework is nearly complete. All instructions are implemented, and all addressing modes for those instructions, all that remains is to implement the BCD versions of a few instructions, and then spend a few hours testing it, before I look at releasing it. David McEwen is looking to use it in the forthcoming version of xNES, and there is interest from a Psion 5 programmer who is looking at writing an Apple][e emulator.

As a sideline, I'm trying to put together a document about how to write an emulator. This is really just a follow up to Marat Fayzullin's general document on the subject, but instead directed at the Acorn platform, and concerned mainly with writing emulators in ARM code, with hints and tips on how to do code certain aspects of the emulator. At the moment it is purely concerned with CPU cores, but I will hopefully add information about other aspects later. I would really appreciate any hints or tips that emulator authors could submit for inclusion, as it is sure to help prospective emulator authors.

The EMU news page recently announced that SNES9x ports to many different platforms, including RISC OS, are being attempted. I mentioned last update that Gareth Long was coding the port, and with this massive support for SNES9x ports on so many platforms a SNES emulator on the Acorn gets more likely by the day.

The next version of Miracle, the Sega Master System emulator, (still in development) features a Z80 bug fix allowing Marble Madness to work properly, and compatibility for VGA monitors.

Ian Molton's Acorn v2600 homepage, for his port of the Atari 2600 emulator is now up at http://www.users.zetnet.co.uk/hawk/v2600/. There is also a new version, featuring a multi-tasking mode. There should be a newer version of the port out fairly soon, with improvements to prevent ROM images needing the /BIN DOS extension, and various other bits and pieces. Unfortunately a speed improvement is not on the cards.

There is a new location for PC card compatibility page, joining me at the cybervillage :o)
http://www.cybervillage.co.uk/acorn/pccard/

Oh, and while you've been reading the news, your net connection's been downloading the definitive proof, that I, David Sharp, am in fact Sonic the Hedgehog ;o)

Ok, so I'm a little late for April Fool's day, but I was bored, and it was more fun than working out how to use URL launching protocols.

Previous update: Tuesday 24/3/98 (ZIP file)