21 Sep
2015
21 Sep
'15
7:16 p.m.
On 2015-09-22 02:09, Jerome H. Fine wrote:
Is there any documentation as to the actual details?
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/rsx11/RSX11Mplus_V4.x/4b/A…
Chapter 3 and 4 give the basics. Chapter 5 through 9 give details in
relations to what the respective chapter is about. Figures on pages 3-5
and 3-6 might give you a goo starting idea of what you can do.
Paul Koning
wrote:
On Sep
21, 2015, at 5:16 PM, Jerome H. Fine <jhfinedp3k at compsys.to>
wrote:
...
Another important aspect is that RT-11 has a few extra instructions
in the overlay handler which determines if the overlay is already in
memory. ...
My question is if TKB overlays also have these extra instructions?
Yes, it also tracks if something is already resident. I haven't
looked into the details. (The only overlay machinery I studied to any
significant extent is the RT-11 one.)
As I mentioned, For the RT-11 overlay handler
integrated with
the LINK program (both are essential), when those aspects
are combined with overlay regions defined by the maximum
size of the overlay in a given region, the first word of every
region is devoted to the overlay (*6) number. Since that
location is not available to the overlay and is unique to the
overlay, the overlay handler can check to determine which
overlay is resident in the region.
With overlay trees in TKB, that method can't be used unless
the line up the tree is intact. I am attempting to visualize the
code which could determine if that is true, but at the moment
it escapes me. Can anyone provide any details?
Otherwise, I can see where the first overlay in any tree can
be determined, but unless a given tree is enforced, there does
not seem to be any way to check if overlays further up the tree
are also resident?
There are no checks that the tree is intact at runtime. This is checked
during the task build. You cannot refer to symbols that are outside you
call tree if you look upwards.
Is there a manual available on overlays using TKB that
is
on the internet?
Gave it above.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol