Infocom Z-code interpreters

Technical Development Interpreters
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22

CBM as first chars in a binary file rings very familiar to me, I looked at basic/xzip hexdump, but things becoming strange:

CBM80 was the “magic signature” identifying an autostart cartridge, but the actual signature was:

XXYYCBM80

where XX is the cold start vector of the cart, and YY is the warm start vector. Not our case, but the next two bytes are intriguing: 00 0C. that is, C000 in the little-endian world of 6502/6510… and C000-CFFF are the 4k of C64 RAM sandwithced between the basic and I/O…

but the file is 12827 bytes long, and from C000, ends at F21B, overwriting the I/O aerea (= major mess on a C64) prior of writing partially in the RAM under the kernel ROM, a thing whose don’t make sense… (continuing the research)

Thanks for another hacking night outside IF coding :wink: :smiley:

Best regards from Italy,
dott. Piergiorgio

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23

Started looking at the c64 code, as that was the machine that I spent most of my infocom-hours on. Enjoying some of the code comments.

    STA FRELO3      ; SET VOICE #3 TO
    STA FREHI3      ; AN AMUSING FREQUENCY
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