New subject: Using printf from Assembly Language in V6, and db.

29 Jun 2021

...
  From: Paul Riley &lt;paul(a)rileyriot.com&gt; 
...
 > (I wrote a note, BITD, explaining how all this
worked; I'll upload it
> to the CHWiki when I get a chance.) 
Now here:

  https://gunkies.org/wiki/PDP-11_C_stack_operation

along with simple examples of args and auto variables, which are both
referenced via the FP.

...
  As a non-C consumer of printf, should I point R5 at
some space for a
 stack and call printf in the same manner as the C example I cited? 
Not necessary to do anything with R5 (you can leave it blank); the only things
a PDP-11 C routine needs are:

- a good stack
- the arguments, and return point, on the top of the stack

csv will set up the frame pointer, making no assumptions about the old
contents of R5 - see the source:

  http://ana-3.lcs.mit.edu/~jnc/tech/unix/lib/csv.s

although it does save the old R5 contents, and restore them on exit.

	 Noel

Re: [TUHS] Using printf from Assembly Language in V6, and db.