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Geoff Wearmouth

@warmtoffee.bsky.social

Press plastic for a living but love the touch of rubber. Assembler of Gosh Wonderful and Looking Glass ZX Spectrum ROMs and my Binary Logic ZX81 ROM bl81.rom

157 Posts88 Follower30 Folgt
Nomen Luni@nomenluni.ie · last mo.

Controversial opinion. I think World of Spectrum should be allowed to die. Yes, it was a wonderful site years ago, and I made many friends there on the forums, but it's been shit ever since Martijn stopped maintaining it, and Spectrum Computing is a more than adequate replacement these days.

Ken Shirriff@righto.com · 2mo ago

Intel introduced the 8087 floating-point chip in 1980 to make math faster. The chip does tangents, square roots, and so forth, but fundamentally everything is computed through additions and subtractions, performed by an adder at the heart of the chip. Let's look at the adder's circuitry... 1/N

A die photo of the 8087 chip, with functional blocks labeled. The die has complex patterns with roughly rectangular shapes. Around the edges, thin bond wires connect the die to the chip's 40 external pins. In the bottom center, the adder is highlighted. It is a tall, thin rectangle in the middle of the "fraction datapath". Above it is the exponent datapath.
ZXVintage@zxvintage.bsky.social · 2mo ago

Sinclair User Jul 1982: ZX81 and Spectrum hardware comparison. Amateur radio feature. ZX81 assembler round-up. Rainbow Computing interview, featuring two people who developed the Spectrum. Game reviews column has disappeared and slightly (1/2)

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Geoff Wearmouth@warmtoffee.bsky.social · 2mo ago

“So if you have bought several ZX Microdrives, you can FORMAT your spare demonstration cartridges and use them as blank cartridges.” - but i had the 1983 and the 1984 demo cartridges and lost the more capable 1984 cartridge by heeding this device.

The 1983 Microdrive Demo cartridges and use by Sinclair Research Limited. Written by Andrew Pennell. The 1983 ZX Spectrum Demo Cartridge menu with seven options only. The 1984 ZX Spectrum Microdrive Demo screen by Andrew Pennell. Only the date is different. The 1984 menu has 10 options instead of seven. Andrew Pennell’s COPIER PROGRAM is in particular useful. Copy any software cartridge to a blank cartridge.
Geoff Wearmouth@warmtoffee.bsky.social · 3mo ago

On Page 30 my 255 byte UDG Editor which squeezed into the ever present printer buffer. Submitted to the magazine in June 1985 long before the news of the 128K ZX Spectrum hit the streets. The printer buffer was used for extra system variable purposes and using the buffer was henceforth verboten.

This was once online. I may type it in for you. The code moved to Utility1 - a screen resident UDG and font editor which is downloadable and 128K compatible.