[pups] What is a 21-21858 chip?

Johnny Billquist bqt at update.uu.se
Sun Feb 18 19:19:45 AEST 2001

On Sat, 17 Feb 2001, Bill Gunshannon wrote:

> Maybe I'm just misunderstanding what is being discussed here, but
> I think the difference is that without the FP11 all you have are
> 4 simple Floating Point Instructions.  FADD, FSUB, FMUL and FDIV.

No, that's the FIS instructions. They are only available on the 11/35,
11/40, LSI-11 and perhaps some other model that I don't remember.

The J11 has the F11 in microcode. The FP11 for the J11 is an accelerator.

> The FP11 adds a number of additional Instructions.  I have never
> had a machine with the FP11 (Hmmmm, wonder if my new 11/93 has it?)
> so I don't know them off the top of my head, but my Macro-11 book
> is near at hand if anybody wants me to look it up.

If someone wants the full F11 instruction set, I think it's available on
the net. Anyhow, yes, your 11/93 have the F11 instruction set. I also
think that the 11/93 cpu always have the accelerator option.
(Hmmm, I'd like to get my hands on an 11/93 CPU, anyone have an extra? :-)


Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt at update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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