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On Sun, 18 Dec 2022, Tom via list wrote:
Bit obscure here but toying with making an 8 bit machine (z80/6502/68008) machine to play with fuzix and vaguely remembered being shown by someone 40 years ago how to bootstrap a machine from scratch - basically typing in some code into memory and then using that to build up a simple set of functions (editor/asm/linker) that could then be recursively improved and wondering if anyone out there has any clue if it exists on the webs?
Your best bet, if you want Fuzix is to search for it and find/build compatible hardware - then boot it from (ee)PROM.
Bootstrapping 8-bit micros is not always easy - but the 8080/z80 systems lend themselves to keting in data with toggle switches (think Altair/Imsai systems). 6502 is harder, but look for the Cactus 6502 system if you want to go down that route.
Most people will program an EEPROM these days, or so something weird like havge a separate CPU control the RAM, poke/dma code into it then let the underlying 8-bit cpu run. This is what I do in my Ruby 6502 and 65816 systems - they run romless but the bootstrap loader is poked into about 200 bytes by the host ATmega MCU.
Going up the the 68K and it's almost always EEPROM.If you want a 6502 or 65816 system that runs BBC Basic or a 32-bit OS written in BCPL then.. https://projects.drogon.net/ruby/
Cheers, Gordon -- The Mailing List for the Devon & Cornwall LUG FAQ: https://www.dcglug.org.uk/faq/