[COFF] machine code translation,as mental architecture models

[Dave Horsfall]

On Sat, 12 Jul 2024, John Levine wrote:

> The details are a litle dim after 45 years, but there was a MOVTUC 
> instruction in the inner loop of printf that scanned for the null at the 
> end of the string.  The /750 had a microcode bug that didn't matter for 
> the way DEC's software used it but broke the libc and I think also the 
> kernel version.  MOVTUC sets six registers and we probably used one they 
> didn't.

I am reminded of the time when overlapped seeks on the RK-11 were 
implemented in Unix, per the Peripherals Handbook.

They didn't work.

DEC responded with "Well, you were running Unix!"...

We then ran "DECEX" (their own diagnostic tool), which indeed failed
on overlapped seekson the RK-11.

It turned out that DEC never used overlapped seeks in their own stuff...

-- Dave