[Simh] PDP7/DECsys bug

[Daniel Baum]

> Does anything work? For example, does integer format output appear to
> be correct?  Other kinds of format specifiers, like H?

Hi Bob,

Everything else appears to work as normal, except the floating point values.

I'd also like to draw your attention to a problem with TOPS-10 Cobol.

Under Cobol-74, a simple numerical variable, declared with "PIC 99", will 
print out as "0J" if its value is 1, "0K" if its value is 2, and "0L" if its 
value is 3.

The same program will produce "1", "2" and "3" with Cobol 68. This is also 
wrong, I think, as they are supposed to produce "01", "02" and "03". Both 
programs seem to have problems with the minus sign too, but I haven't worked 
out exactly what it is doing wrong under various circumstances.

This is with simh 3.71 under Windows XP.

Thanks,

Daniel

>
> The problem could be in the simulator, or in the transcribed copy of
> the compiler or run-time library (the DECtape was nearly 40 years
> old).  There might be a clue based on what works and what doesn't.  If 
> not...
>
> The PDP-7 simulator has a history function that can record the most
> recent 65K instructions (and with a source change, even more than
> that).  You can use this to trace the doings of the simulator during
> the Fortran print statement.  Without source for the Fortran library,
> it will be difficult to understand what's going on, though.
>
> /Bob Supnik
>
>
>
>>----------------------------------------------------------------------
>>
>>Message: 1
>>Date: Sun, 3 Jun 2007 08:44:25 +0300
>>From: "Daniel Baum" <daniel at type34.info>
>>Subject: Re: [Simh] pdp7/decsys bug?
>>To: "SIMH List" <simh at trailing-edge.com>
>>Message-ID: <006901c7a5a2$3ecf3380$0501c80a at IBM39EA7112605>
>>Content-Type: text/plain; format=flowed; charset="ISO-8859-1";
>>         reply-type=original
>>
>>
>>Hi all,
>>
>>This is both an answer to the previous posts on this thread, and a report 
>>of
>>some more progress in getting things to work on simh.
>>
>>I tried what Dave suggested. Decsys does not appear to be trying to use an
>>unimplemented instruction. Therefore I still have not managed to solve the
>>Decsys Fortran problem.
>>
>>To remind everyone what I'm talking about: Decsys Fortran does not seem to
>>work properly with floating point values. It was suggested that it might 
>>be
>>trying to call a floating point processor, but this does not seem to be 
>>the
>>case.
>
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