From: Paul Riley <paul@rileyriot.com>
To: Noel Chiappa <jnc@mercury.lcs.mit.edu>, Clem Cole <clemc@ccc.com>
Cc: tuhs <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] Using printf from Assembly Language in V6, and db.
Date: Tue, 29 Jun 2021 22:18:26 +1000 [thread overview]
Message-ID: <CAD05_j0=QWQi+qDpkgmz3oqXK7qKifzouwxSd0=1nne=XW-qMA@mail.gmail.com> (raw)
In-Reply-To: <20210628203728.8305818C090@mercury.lcs.mit.edu>
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Thanks Noel, Clem for your always generous and highly informative answers.
I'll digest that and enjoy using C routines in my assembly programs!
Paul
*Paul Riley*
Email: paul@rileyriot.com
On Tue, 29 Jun 2021 at 06:37, Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:
> > From: Paul Riley <paul@rileyriot.com>
>
> >> (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
>
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next prev parent reply other threads:[~2021-06-29 12:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 20:37 Noel Chiappa
2021-06-29 12:18 ` Paul Riley [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-06-28 4:48 Noel Chiappa
2021-06-28 11:27 ` Paul Riley
2021-06-28 13:48 ` Clem Cole
2021-06-28 2:34 Paul Riley
2021-06-28 3:27 ` Paul Riley
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