retrocomputing

Bilingual

Autoregressive Language Model on the 6502 Processor
a day ago
- The project runs a language model on a BBC Micro (6502 CPU) with only 25KB of user memory (9KB code, 13KB weights).
- The model uses BitNet ternary quantization (-1,0,1) packing 4 parameters per byte, storing 52k parameters in 13KB.
- A Mamba (SSM) architecture is chosen over attention or GRU because it requires fixed-size state and avoids instability issues on the 6502.
- Inference is coded in C (CC65) and transferred to the BBC Micro via a custom audio cable and PlayUEF.
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The MOnSter 6502 (2016)
8 days ago
- The MOnSter 6502 is a giant transistor-scale replica of the MOS 6502 microprocessor, measuring 12x15 inches with over 4000 surface mount components and 167 indicator LEDs.
- The project is still underway and the first prototype will be shown at the Bay Area Maker Faire, though it may not be fully functional yet.
- The MOnSter 6502 is not currently sold as a kit or product, but there is a mailing list for updates.
- Reader comments express strong interest in purchasing the replica as a kit or bare board, with some suggesting its potential as a teaching tool and display piece.
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Using Claude to re-create extinct software – Matlab from the 1980's
10 days ago
- The author searched for over 22 years for a 1980s MATLAB version (around 3.x) to run on a MicroVAX II, but only found the 1982 FORTRAN release.
- Later versions with user functions, script files, and a signal processing toolbox were elusive; Cleve Moler was contacted but passed away.
- Using Claude AI, the author performed a clean-room re-implementation of MATLAB to the 3.x spec, adding m-file execution for extensibility.
- The project, named VAXLAB, was developed on a real MicroVAX II with Compaq C compiler, including REGIS/SIXEL graphics and a full test suite.
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Building GCC 1.27
10 days ago
- GCC 1.27, released in 1988, was the first version to support the x86 CPU, and the author built it on a modern 64-bit Ubuntu system.
- The build process was based on Mikhail Maltsev's work but required updates for 64-bit OS, system headers, and enabling the DBX debug format.
- Modern assembler, linker, and debugger handle GCC 1.27's output without issues, and many modern command options like -O, -g, -W work as expected.
- Build steps include installing gcc-multilib, downloading the source and patch, configuring via symlinks, and performing a three-stage bootstrap (make, stage1, stage2) followed by installation.
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Bringing Swift to the Apple ][
a month ago
- SwiftII is a Swift-like mini development environment for the Apple II, inspired by Apple Pascal's bytecode approach.
- The project targets original Apple II hardware with constraints like 40,704 bytes of main RAM and uses a bytecode VM instead of native 6502 code.
- It features a REPL, file browser, text editor, and compiler, with support for digraph input on pre-IIe keyboards due to character limitations.
- Memory banking (e.g., Saturn 128K or IIe aux RAM) allows expanded features and larger programs, but requires separate disk images for different hardware.
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retrocomputing

Autoregressive Language Model on the 6502 Processor

The MOnSter 6502 (2016)

Using Claude to re-create extinct software – Matlab from the 1980's

Building GCC 1.27

Bringing Swift to the Apple ][