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Thread: Fun with CC40s

  1. #1

    Default Fun with CC40s

    I've been poking around in ROM, trying to learn a bit more about

    Hook tables in System RAM. A few years ago Acadiel asked me to

    write a pgm to dump the CC40 system ROMs - I'd thought the 4-8K

    ROM pages @>D000-E000 were accessible in DEBUG with the "R"

    command, but this turns out to be only partially true; you can only

    see Page 3 in DEBUG with the "D" or "M" commands - So I wrote a

    short asm routine that uses the ROM paging bits @ P25.0 & P25.1 to

    read the 4 ROM pages consecutively into cartridge RAM, where they

    are directly accessible from BASIC. This turns out to be useful for

    disassembling ROM with DEBUG, so I thought I'd post the routine I'm

    using now - It moves the page you're interested in from >D000-E000

    to >5000-6FFF in cartridge RAM; you can put it anywhere you want,

    but 4K boundaries are convenient, as >D000 = >5000, & so on... And

    sInce the code's in RAM you can set breakpoints & run it, after adjusting

    hard-coded addresses...

    Not a world-beater, but very short (39 bytes) which means you can enter

    the code by hand, through DEBUG - No PCIF necessary.

    Jack

  2. #2

    Default

    Bugfix - Change >201A in attachment from >7F to >FF.

    Attachment has also been corrected - I hope...
    Attached Files Attached Files

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