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Patching 68K Software – SimpleText

105 points by mmoogle

by mjg59

4 subcomments

This is beautiful, but the real takeaway should be that even proprietary software you only have binaries for is still mutable. The computer runs the code you want it to run. We always need to maintain that and prevent scenarios where general purpose computers stop being the default.

by unwind

2 subcomments

For people not used to reading MC8k assembly [1], it's helpful to point out the basic fact that the syntax is in general
```
    opcode  source, destination
```
which is the other way around from most contemporary ISA:s. So a line like
```
    move.l d0, -(a7)
```
will first decrement the value of register a7, then write the contents of register d0 to the resulting address (it's a "push" for a downwards-growing stack).
Edit: added Wiki-linkage.
[1]: https://en.wikipedia.org/wiki/Motorola_68000#Instruction_set...

by musicale

1 subcomments

I thought option-resize was supposed to resize the default (new document) window?
My recent pet peeve is that macOS doesn't seem to remember window sizes and locations properly. Things are certainly complicated by multi-monitor setups, but it seems like some sensible default behavior could be implemented.
I don't dislike the column browser, but I wish macOS would preserve/revive its spatial UI in both the Finder and document window positions.

by TomMasz

1 subcomments

I fondly remember patching 68K code in memory on an industrial control system my company was developing. I was able to decode the instructions just by looking at the hex display. Daresay, I could not do that with any modern system.

by robinhouston

0 subcomment

I used to love doing this sort of thing back in the early '90s. What a nostalgic read! Funny that there are still people doing it today.

by girl2

0 subcomment

I had to do this at work once