markgbeckett.bsky.social
I am an academic, computational scientist, and research-programme manager, working in high-performance computing, though often found tinkering with 1980s 8-bit micros.
60 posts
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26 following
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And if you'd like to experience what it was like to use and program the MPF-1, you can run the MPF-1 ROM on the @tynemouthsw.bsky.social #Minstrel4th using this revised ROM that I have created, including the printer and EPROM programmer add-ons - github.com/markgbeckett...
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Great game. More of a simulator than a racing game. I spent ages trying to get a fastest lap on Paul Ricard circuit.
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Good progress made on finalising computing needed on our quest to #CaptureTheCosmos. @vrubinobs.bsky.social @lsstuk.bsky.social
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Maybe if you wanted to add two floating point BCD numbers. You'd probably want to align the mantissas.
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Yes, I think it's a quick way to do that for a game. Zilog manual includes an example of multiplying a BCD integer by 10 - www.zilog.com/docs/z80/um0... (p. 27). Retro-overflow suggests it is also useful for floating point BCD arithmetic, dealing with the mantissa; I'd need to think about that.
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Then you could tell us all about uses of the #Z80 RLD command. 😁
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I went slightly out of my way to find an excuse to use BCD in an implementation of Hampson's Plane for #ZX80. I had to keep the timing of each game loop constant so that screen didn't flicker and BCD helped with that. github.com/markgbeckett...
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Ultimate #ZX81 model?
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Sorry to hear that. Hope things work out okay.
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Better QA on original ROM, which was pretty buggy and cheaper Microdrive cartridges would have helped a lot. I hear people were put off by lack of on/off switch, which made people worry about quality. Sad it didn't do better. I really like QL and it's BASIC was excellent.
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Teletext-compatible?
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Next you will want one of these - z80kits.com/shop/ym2149-..., which allows you to enjoy the Boldfield Soundbox on your #Minstrel4th/ #Minstrel4D. Some notes on how to do this and software at github.com/markgbeckett..., plus I've patched #JupiterAce games Valkyr and Centipede. #retrogaming
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Hopefully Colin Dooley will be happy for me to try to complete his excellent port of #Centipede to #JupiterAce, by adding in the spider feature and Boldfield joystick support. Should then run well on @tynemouthsw.bsky.social #Minstrel4D.
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In eight bits, that's zero 😮
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Very interesting article #retrogaming
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One particularly intriguing finding is this graphic, which is never used. Looks as if Colin at least contemplated implementing the spider from the original Atari game! #retrogaming
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Hangs head in shame and walks away ...
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I'm assuming it's not an MSX?
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I had forgotten about the colour clash when loading the Psion screen over the top of the Horizon logo!
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A bit late to the party, but still visible. #venus
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I should have gone with Logo, maybe.
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103 bytes! Impressive
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Also, if you run on a @tynemouthsw.bsky.social #Minstrel4th/ #Minstrel4D and have an #RC2014 Digital I/O card, you get an Alien-style proximity sensor!
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You should also try the #JupiterAce version. I worked a lot on getting the timing right: I think it is about 90% there and that it holds up well against the #ZX81 original - github.com/markgbeckett.... It's also mostly written in #Forth, so easier to into source code (possibly).
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Only if I live at Edinburgh Castle!
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You could check out the sunrise and sunset times whenever you like! github.com/markgbeckett...
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I've made a first attempt #vccc2024
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Are there enough row in top half of your present?
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🤔
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That's my Sunday sorted !
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Read all about it at blog.tynemouthsoftware.co.uk/2022/03/not-...
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This is the state I acquired it in, by the way. After much discussion involving @tynemouthsw.bsky.social, the orignal owner, and me, we decided not to try to restore it but leave it as is, as a testiment to the bedroom coders and electronics hackers of the day. #retrocomputing
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The finest example of a computer I would have loathed in 1982 but is now my favourite retro-computer by far, and the reason I re-learned #forth after 40+ years. Sadly my own Jupter Ace (donated by a former Jupiter Cantab employee) is in a very sorry state.