Commstar 1.40 disassembly

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Commstar 1.40 disassembly

Post by johnkenyon » Fri Jul 13, 2018 4:51 pm

Here's my annotated disassembly of Commstar 1.40

Note that it's written to be assembled using the xa 6502/RC65C02/68516 cross-assembler.
For the uninitiated, this means:
1) $FF not &FF for hex
2) % indicates binary (used once)
3) ROR replaces ROR A, ROL replaces ROL A, and ASL replaces ASL A

To assemble:
xa whatever.asm -o whatever.hex

Hacker Short cuts:
"I want to hack the defaults"
TERMDEF - Terminal mode defaults
PRESDEF - Prestel mode defaults

"I want to implement a function assigned to a Fn key in chat mode"
$92F5 Terminal mode function key lookup table (F9, COPY does nothing)
$94BE Prestel mode function key lookup table (F4 and F6 keys do nothing...)
So to create a new function key, assemble custom code at $A000 onwards and then insert the address into the table.
(Make sure you pad out the image to 16k)

Hope this is useful

Commstar disassembly (text with CRLF line terminators)
(94.59 KiB) Downloaded 7 times

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