[TUHS] v6 debugging

Will Senn will.senn at gmail.com
Sun Jan 24 02:58:31 AEST 2016


I'm finally returning to my study of v6 after digging a bit further into 
assembly language and "other" pdp-11 operating systems. I even managed 
to get hello, world working in assembly in v6 and interestingly enough, 
I actually see how it works... for the most part :). Mini-note here:


My question for y'all today is as follows (asked previously with a much 
larger gap in understanding):

How did folks debug assembly routines in Unix v6, back in the day?

I realize that most folks didn't do assembly, but some did and I'm 
curious what their approach might have been.

After having worked with RT-11 for a bit, I can see how I might develop 
using RT-11 and then "port" a program across, but that seems less than 
ideal. Here is my short list of missing features as I see them:

1. No listing file/cross reference list created by as.
2. No map file created by ld.
3. No debugger that I can find.
4. This is not a missing feature, but it deserves inclusion in the list, 
the command as has possibly the most terse error messages I have ever 
seen - B 12? Really? Thankfully, the awesome man command comes to the 
rescue with the list of error codes.

My workarounds include using OD to view the generated machine code and 
adding mesg calls.



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