Re[2]: [fasm-help] BIOS initial jmp
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From: Anthony <an...@do...> - 2002-11-15 11:29:00
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Hi Fabio, Thursday, November 14, 2002, 9:29:13 PM, you wrote: FB> Sorry, can't help you with this question (others, or Tomasz himself, will FB> surely do it soon).. but I'd want to ask you something: FB> When you develop your BIOS, you'll want to test it from time to time: do FB> you flash it every time, or you know any way to write to the shadow ram? FB> Any other detail you may want to share? I'm interested into writing my FB> own BIOS too. I'm writing a fully 32-bit BIOS with built-in BASIC-like language, it should boot within about 3 seconds (max)... My system will have SCART RGB out via the VGA connector - to be linked direct to a TV, not a VGA monitor! I'm basing it on the PLE133 chipset as this is used in EPIA motherboards, i'm using the C3 processor as this is a cool running 800Mhz processor (fan not required!)... Its all also pretty cheap & easy to get! The PLE chipset has sound/graphics etc all "built-in" so I don't need to talk to "other" video chipsets, I can optimise the system for the video chipset onboard. The C3 is x86 compatible and has a good future as this and the next versions of the processor have some nice "secret" features... :) Currently i'm doing it all the VERY hard way, i'm reflashing every test run... Soon I will have an old style monitor or debugger running, so I will then be able to upload updates... I have made a "sub-site" on my website for the project at www.doubledutchdesigns.com - it's currently called retro machine (or something similar) as I don't yet have a proper name for it! The hard bit was getting anything to work at all... Don't forget that until you get things working a little bit, you have hardly any access to hardware... A great help was a port $80 (0x80) debug card, i found a cheap source at "Los Altos" http://www.losaltos.co.uk/ - it was £15 +vat +p&p = just over £20... (30 euros?)... If your not in the UK, then do a search for EP-P80P made by EPoX Computer Company - they are about the same price worldwide... With the card you can (from reset!!!) output to the port a number (A POST CODE), this can be anything you want - At each routine output a different number, if the display "freezes", then you know that the pc has locked up at a particular routine. When trying to track down one particular bug that locked the machine I had a different number per line of the routine!!! -Anthony |