On Tue, Feb 16, 2010 at 7:48 PM, McKown, John <john.mck...@healthmarkets.com > wrote:
> > -----Original Message----- > > From: IBM Mainframe Discussion List > > [mailto:ibm-m...@bama.ua.edu] On Behalf Of Sam Siegel > > Sent: Tuesday, February 16, 2010 1:44 PM > > To: IBM-MAIN@bama.ua.edu > > Subject: Re: Fastest branch instruction > > > <snip> > > > > You may want to look at some of the new compare instructions > > such as compare > > logical immediate and branch relative. The branch is > > generated inside the > > instructions when the comparison fails. > > Those a z10 only. We are stuck for who knows how long on a __purchased__ > z9BC. > > > > > You may also want to try an experiment with compare halfword > > immediate. (I > > know it is a signed compare but since your are testing for > > equal/not equal > > you should be ok.) You can compare two bytes at a time. > > Along those lines, > > depending on occurrences and lengths of blank character runs > > you may want to > > pre-load a 32 or 64 bit register w/spaces and then fetch 4 or > > 8 bytes at a > > time and do a compare logical register. Be sure to only > > start fetching once > > the source is on a word or double word boundary ... otherwise > > register load > > performance will suffer. Basically you will need to use a > > CLI loop until > > you get to the correct boundary. > > Hum, an interesting thought, for sure! > > > > > Compile a C or Metal-C program with memcmp under high > > optimization and the > > correct arch level. Take a close look at the generated code. > > Try it with a > > fixed length target (char a[ 10 ]) and a variable length > > object (char *a). > > The code is very interesting. > > No C compiler here. No money, either. > I thought C was moved into the base. Darn it! :-) > > > > > Cheers > > Sam > > > -- > John McKown > Systems Engineer IV > IT > > Administrative Services Group > > HealthMarkets(r) > > 9151 Boulevard 26 * N. Richland Hills * TX 76010 > (817) 255-3225 phone * (817)-961-6183 cell > john.mck...@healthmarkets.com * www.HealthMarkets.com > > Confidentiality Notice: This e-mail message may contain confidential or > proprietary information. If you are not the intended recipient, please > contact the sender by reply e-mail and destroy all copies of the original > message. HealthMarkets(r) is the brand name for products underwritten and > issued by the insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake > Life Insurance Company(r), Mid-West National Life Insurance Company of > TennesseeSM and The MEGA Life and Health Insurance Company.SM > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
