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26053ROM Bootloader Issues

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  • Kyle Owen
    Jun 2, 2012
      Hi guys,

      So I recently copied 8k BASIC to (4) 2kB EEPROMs in hopes that I could make a bootloader to copy the contents into RAM, eliminating the 5 minutes or so that it would otherwise take to load BASIC via RS-232. 

      Anyways, I'm completely stumped as to why my very simple bootloader isn't working correctly. The code can be found here: http://pastebin.com/jbrTHdnX

      It actually does copy the contents correctly, but fails to exit to the monitor on time. The DEX instruction can only update the zero flag, so I am fairly limited on branches. It should exit the loop as soon as the index register is zero, but instead, it exits well after the index register underflows. 

      Any help would be much appreciated, as always. Thanks!

      Kyle
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