[Info-vax] Y3K for PDP-11 Operating Systems

[glen herrmannsfeldt]

In vmsnet.pdp-11 vandys at vsta.org wrote:
> In alt.sys.pdp11 Johnny Billquist <bqt at softjar.se> wrote:
>> I know that for some things, actually coding using more primitive 
>> instructions on the (older) VAXen turned out to be faster than to use 
>> the fancy instructions, but I would not have thought that was true for 
>> things like MOVC or LOCC, but I might very well be wrong.
 
> I'm pretty sure we ended up with a hand coded bcopy() back in the day.
> It might've been that we could do optional initial odd, and then move
> as words.  I think I heard that later Vaxen microcode would do that too.

I remember stories from near the beginning of the 11/780 about
the polynomial expansion and bounds check instructions being
slower than doing either without those instructions.

I wouldn't be surprised if the string instructions were slower,
but I don't remember any stories about them.

-- glen