When Dan Greiner used to present new hardware instructions at SHARE, he
used to mention some had uses in micro/millicode. He talked about
instructions he had personally pushed for because he could see
performance benefits by using them in millicode. Those of us attending
couldn't think of any practical uses.
From my understanding of a COBOL compiler presentation at SHARE, they
cited performance benefits by using the new SIMD instructions to replace
search instructions (SRST?), because the SIMD instructions were what the
millicode used to implement the instruction.
Gary Weinhold
Data Kinetics, Ltd.
On 2015-03-11 10:58, Mike Shaw wrote:
β
On Wed, Mar 11, 2015 at 10:49 AM, John McKown <[email protected]>
wrote:
Given some of the new instructions, such as LGZR, I wish IBM would
publish a manual with a title like: "What were the architects thinking
of? Explanation of the reasons behind the instructions in the z
architecture".
β...
"βTo make the code compiled by the C/C++ compiler and/or WebSphere / Java
code run faster" is the answer to ANY "Why?" question about new
instructions, IMHO...
β
Mike Shaw
MVS/QuickRef Support Group
Chicago-Soft, Ltd.
