Very nice! I'll just eliminate the LTR as other posts have shown and use the AR R15,0 / BR R14 that Mr. Ehrman showed as well. I first came up with my "solution" when I was a wee, young sysprog and have never bothered to change. "If it ain't broke, don't fix it."
CALL ... LTR R15,R15 JM BAD_RC CHI R15,MAXJUMPS LA R0,3 NR R0,R15 JNZ BAD_RC LARL R0,JUMPS AR R15,R0 BR R15 JUMPS J RC0 J RC4 J RC8 MAXJUMPS EQU (*-JUMPS)/4 I did the LTR / JM to include checking a negative RC, instead of the CL Tony used, because I wanted to avoid needing a base register. Yes, I know I need one for the literal pool if I have any literals. I try to avoid literals as much as possible by using immediate instructions where the value is defined in an EQU. -- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets(r) 9151 Boulevard 26 * N. Richland Hills * TX 76010 (817) 255-3225 phone * 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 > -----Original Message----- > From: IBM Mainframe Assembler List [mailto:ASSEMBLER- > l...@listserv.uga.edu] On Behalf Of Tony Thigpen > Sent: Monday, August 27, 2012 12:19 PM > To: ASSEMBLER-LIST@LISTSERV.UGA.EDU > Subject: Re: which instructions should I use? > > Your code requires 2 scratch registers. The following uses just 1 > scratch register and does not require literal storage: > > LA R0,3 > NR R0,R15 > LTR R0,R0 > BNZ BAD_RC > > (I still have to use code that works on boxes without the jump > instructions.) > > Tony Thigpen > > > -----Original Message ----- > From: McKown, John > Sent: 08/27/2012 11:34 AM > > Destroys the contents of R15, so I guess I would load R15 into, say, > R0 and do the OR operation on R0. However, I'm on a z9 and will likely > never be on anything more advanced. So I'll need to load the mask into > another register, say R1. That would either require an L R1,variable or > literal (=X'FFFFFFFC'), or do an: AHI R1,X'04' followed by an LCR > R1,R1. I don't know which of those is "better". I guess the Load would > be more easily understood by even a novice. > > > > LR R0,R15 > > L R1,=A(-4) > > OR R0,R1 > > CR R0,R1 > > JNE BAD_RC > > > > -- > > John McKown > > Systems Engineer IV > > IT > > > > Administrative Services Group > > > > HealthMarkets(r) > > > > 9151 Boulevard 26 * N. Richland Hills * TX 76010 > > (817) 255-3225 phone * > > 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 > > > > > >> -----Original Message----- > >> From: IBM Mainframe Assembler List [mailto:ASSEMBLER- > >> l...@listserv.uga.edu] On Behalf Of John Gilmore > >> Sent: Monday, August 27, 2012 10:20 AM > >> To: ASSEMBLER-LIST@LISTSERV.UGA.EDU > >> Subject: Re: which instructions should I use? > >> > >> Register contents that are a multiple of 4 are all of the form > >> > >> xxxxx...xx00 > >> > >> Inclusive ORing such a value with the mask > >> > >> 11111...1100 > >> > >> and testing the result for equality with this same mask then yields > a > >> simple, low-overhead test for a multiple-of-four value. > >> > >> --jg > >> > >> On 8/27/12, McKown, John <john.mck...@healthmarkets.com> wrote: > >>> Thanks for the technique. I'm not sure that I like the NILL > >> instruction at > >>> this point. It could change an "invalid" (as in "not planned for") > RC > >> into a > >>> "valid" RC. Looks like maybe I could use TMLL to just test. (TMLL > >>> R15,X'000C') > >>> > >>> -- > >>> John McKown > >>> Systems Engineer IV > >>> IT > >>> > >>> Administrative Services Group > >>> > >>> HealthMarkets(r) > >>> > >>> 9151 Boulevard 26 * N. Richland Hills * TX 76010 > >>> (817) 255-3225 phone * > >>> 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 > >>> > >>> > >>>> -----Original Message----- > >>>> From: IBM Mainframe Assembler List [mailto:ASSEMBLER- > >>>> l...@listserv.uga.edu] On Behalf Of Martin Truebner > >>>> Sent: Monday, August 27, 2012 8:15 AM > >>>> To: ASSEMBLER-LIST@LISTSERV.UGA.EDU > >>>> Subject: Re: which instructions should I use? > >>>> > >>>> John, > >>>> > >>>>>> you still need base+displacement .... desire for an index > >> register; > >>>> > >>>> They come in most cases when there is space in the nibbles for it. > >> But > >>>> for the case you cited there is no need to cover code in > >>>> "procedure division" with a base. (Dynamic storage and literalpool > >>>> do have a base!) -Here is how: > >>>> > >>>> CALL PROGRAM,(PARM1,PARM2),VL > >>>> CHI R15,=Y(MAXENTRIES) > >>>> JH INVALID_RC > >>>> L R15,=A(RC0,RC4,RC8,RCC)(R15) > >>>> BR R15 > >>>> > >>>> Your addon (check for a valid rc) could also be done with this > >>>> > >>>> NILL R15,X'000C' > >>>> > >>>> as a result you only have valid combinations left over (Yes I > >> cheated > >>>> and added an entry for C). > >>>> > >>>> -- > >>>> Martin > >>>> > >>>> Pi_cap_CPU - all you ever need around MWLC/SCRT/CMT in z/VSE > >>>> more at http://www.picapcpu.de > >>> > > > >
