Noooooo!!!!

That was what I was trying to say: you can no longer say "instruction X takes n 
cycles." You just cannot. That is why IBM no longer publishes such a thing. At 
best case an LR or an L take "no time at all" -- read what I wrote earlier. 
Worst case an LR takes a little while and an L takes a really long time. (How's 
that for technical precision?)

Charles


-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf 
Of Brian Chapman
Sent: Tuesday, August 13, 2019 7:52 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Instruction speeds

Thanks Giliad. This is what I was searching for. I understand that the
timings in this document are very old and probably wildly inaccurate for
today's Z systems, but would it be on a relative scale? Would a LR be twice
the speed of a L?



Thank you,

Brian Chapman


On Tue, Aug 13, 2019 at 10:28 AM Giliad Wilf <
000000d50942efa9-dmarc-requ...@listserv.ua.edu> wrote:

> On Mon, 12 Aug 2019 20:48:18 -0400, Brian Chapman <bchapma...@gmail.com>
> wrote:
>
> >Hi everyone,
> >
> >I did some searching, but I didn't find anything that really discussed
> this
> >on the topic that I'm interested. Is there anything published that
> compares
> >the cycle times of the most used instructions?
> >
> >For example; moving an address between areas of storage. I would assume
> >that executing a LOAD and STORE would be much quicker than executing a
> MVC.
> >
> >Or executing a LOAD ADDRESS to increment a register instead of ADD HALF
> >WORD.
> >
> >Or does this really matter as much as ordering the instructions so they
> are
> >optimized for the pipeline?
> >
>
> There used to be, with every new IBM System/360 machine, a "Functional
> Characteristics" publication stating "Instruction Times" in microseconds.
> Here is one for the IBM System/360 Model 85:
>
>
> http://www.bitsavers.org/pdf/ibm/360/funcChar/A22-6916-1_360-85_funcChar_Jun68.pdf
>
> See page 27.
>
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