[Simh] Porting simh for IBM VM/CMS

[Dave G4UGM]

>Dave, 

 

>You need not be amazed; your idea is sound and as you mentioned, getting the brackets

>right was the worst of it.  Congrats on the code transformation from simply "nasty" to

>"really horrid" and finally "truely noxious".  I'll insert some line breaks and comments to

>make it potentially readable.  (Here I thought APL was the only write-only language.)

 

>Perhaps this original code struck you as nasty because it is really a hidden OS dependency,

>is it not?  Or are character set arrangements not included in that realm?

 

Well it’s a character set dependency and a really neat piece of optimization. However its hiding something in a bit field, a trick which in High Level languages has always caused me problems in the past.

I think it would be more portable to have the Alphabet as a string “ABCDEFGHIJKLMNOPQRSTUVWXYZ” and then search through it for the wanted character, but of course much slower…

 

As Michael Jackson once said :-

 

"Beer may cause you to digress--and lead a happier life"

 

(that was another late and much lamented Michael Jackson aka “the beer hunter” - https://en.wikipedia.org/wiki/Michael_Jackson_(writer)”

 

Michael Jackson author of – Principles of Program Design - https://en.wikipedia.org/wiki/Michael_A._Jackson

 

Had a more apposite saying, that is  “we will look at optimaztion – but later on” , perhaps its not time…

 

>Thinking about related matters, do I need to be concerned that the IBM systems are

>big endian?  It appears that simh takes this into account with the sim_finit routine in sim_fio.c,

>but there could be other places with data coding assumptions not fitting the /370 architecture.

 

It possible, but its probably easier to try and test, rather than to find.

 

>For the moment, I hacked the "attach" <dev>" code to avoid a rb+ file open attempt since

>the CMS implementation of the stdio package does not support simultaneous r/w file access.

>This will surely prove to be another big problem, but for now the attach is successful for an

>existing file.

 

You didn’t say which IBM platform you were running this on, and which “C” compiler….

 

Fritz

 

Dave

 

From: rubhone at aol.com [mailto:rubhone at aol.com] 
Sent: 01 August 2015 18:32
To: dave.g4ugm at gmail.com
Cc: simh at trailing-edge.com
Subject: Re: [Simh] Porting simh for IBM VM/CMS

 

-----Original Message-----
From: Dave G4UGM <dave.g4ugm at gmail.com <mailto:dave.g4ugm at gmail.com> >
To: rubhone <rubhone at aol.com <mailto:rubhone at aol.com> >
Cc: 'simh' <simh at trailing-edge.com <mailto:simh at trailing-edge.com> >
Sent: Fri, Jul 31, 2015 7:09 am
Subject: RE: [Simh] Porting simh for IBM VM/CMS

I am amazed, and very glad, it works, been ages since I wrote any “C” ….

.. and as for threads, well they are hidden in the headers, and should just pick up again. 

 

Dave Wade

G4UGM

 

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