Re: SV: Rexx bug?
From REXX/VM Reference - Quote Certain character strings are numbers even though they do not appear to be numeric to the user. Specifically, because of the format of numbers in exponential notation, strings, such as 0E123 (0 raised to the 123 power) and 1E342 (1 raised to the 342 power), are numeric. In addition, a comparison such as 0E123=0E567 gives a true result of 1 (0 is equal to 0). To prevent problems when comparing nonnumeric strings, use the strict comparison operators. /Quote Thomas Berg wrote: -Ursprungligt meddelande- Från: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] För Patrick O'Keefe Skickat: den 10 mars 2008 20:50 Till: IBM-MAIN@BAMA.UA.EDU Ämne: Re: Rexx bug? On Mon, 10 Mar 2008 19:16:26 +, Ted MacNEIL [EMAIL PROTECTED] wrote: The simple answer is that the designed the interpreter that way. Whenever possible numeric strings are interpreted as numbers first, unless you perform unnatural acts of coding, regardless of whether you quote it or not. While I've known this for years, I've never given it much thought. I've been coding REXX since around 1988 but never (knowingly) ran into this ... probably because I've never needed to use scientific notiation in REXX and never even knew it was supported. I now wonder how many comparisons are waiting to fail on me. I can just picture very different and unexpected results from the two invocations x= SOMEEXEC(00E0 00E8) y= SOMEEXEC(00F0 00F8) where REXX sees 2 equal numbers in the first case and 2 different strings in the second case. No. REXX sees 1 string in each case (00E0 00E8 and 00F0 00F8). Try x = 00E0 + 00E8 and y = 00F0 + 00F8 You will get an error in the latter case. Regards, Thomas Berg _ Thomas Berg Specialist IT Utveckling Swedbank AB (Publ) -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html .. For: [EMAIL PROTECTED] -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: CMS PEEK command - how to delete all SHADOW lines
[EMAIL PROTECTED] wrote: In article [EMAIL PROTECTED] you write: [...] What I meant is that XEDIT has no sequence as simple as: EXCLUDE ALL FIND wombat ALL Not correct. All does just that. ALL /wombat/ ... looking at the display, I decide I want to see additional lines, so I: FIND xyzzy ALL ... now I see the lines containing wombat and/or xyzzy for a single additional command with a single target. I once wrote an XEDIT macro to do this, but I believe the supplied ALL XEDIT doesn't do anything close. You are correct in that the IBM supplied Xedit + IBM supplied macros (one of which is ALL) do not do this. However macros such as INCLUDE and EXCLUDE and/or various other names have been floating around the user community since ALL became available. Some of them may even be yours. The syntax is different from ISPF because ISPF != Xedit. Results are same or similar. Use all/wombat/|/xyzzy/ to display lines with wombat and/or xyzzy then shad off to hide the x line(s) not displayed lines -- Chris Langford, Cestrian Software: -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Poster of computer hardware events?
Chase, John wrote: Hmmm. A nanosecond is one billionth of a second, so the long rope would have to be a billion times longer that the short one. Grace Hopper gave out nanoseconds in the form of a piece of wire (about 11.75 inches long). This represented the actual distance light travels in 1 nanosecond. Comparison was made to 1000 foot rolls (a microsecond). -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Code after RUNNING status? - reformatted -
Whoops. EXEC was pasted with lots of blanks For Vista I rewrote Tom's 'VSTEXEC' TSO command for VM. It is available athttp://www.tombrennansoftware.com/other.html as VMVISTA VMARC This allows changing the Window Title (and other options) of the current session from CMS only if the emulator is VISTA Then EXEC I use is -- -Start EXEC -- /* Set Title Bar on Vista Screen */ parse arg title if title='' then do identify (lifo if rc0 then exit rc pull us at sysid . title='VM 'left(userid(),8)' at 'sysid end 'VMVISTA SetOption(General,WindowTitle,'title')' -End EXEC --- By changing the Title sessions are named even when the session is minimized. Chris Rob van der Heij wrote: My approach to start the termulator sessions in the same order and have the most popular sessions always in the same session (and use Alt-1, Alt-2 to go to the right system). I am using Tom Brennan's Vista tn3270 which lets me also color the frame and border of the session. It shows the IP hostname in frame of the window too. And I use the ID command a lot when jumping through a dozen sessions. In the past I have also worked with different colors for some of the output via the CP SCREEN command (like red CP output on the production systems - as if that were enough to prevent that accidental shutdown). Rob .. For: [EMAIL PROTECTED] -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Rotational Positional Sensing (RPS)
Using a sector number of x'00' effectively disabled RPS on devices that did care. Edward Jaffe wrote: Richards.Bob wrote: Do you know of any DASD subsystem that does not publish RPM information? I thought not. They still care. grin But kidding aside, I would suspect the last time it really mattered it would be a real 3990-3390 SLED. Am I missing something in your question here? I assume RPS sector numbers are *ignored* for ESS and newer devices. But, the IBM documentation does not confirm my assumption. Rather, they still fully document the RPS factors that are returned, how to calculate the sector value, etc. I noticed the tuning Redbook said that RPS delays cannot occur on ESS. But, says nothing about what, if anything, the sector number you (are expected to?) provide might be used for. Setting the sector number to x'FF' in the ECKD locate record parameter list disables the use of RPS. I'd like to see us do that for all modern DASD devices. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Rotational Positional Sensing (RPS)
Actually x'00' disconnects until position is just before index point so the following search Id starts with index point count at 1, maximum scan for the Id will be one revolution till next time index point is detected. Using x'FF' will not disconnect and search id starts at current position which could be just after index point so maximum rotation could be almost two revolutions till index point is detected twice. (IBM Mainframe Discussion List) wrote: In a message dated 7/24/2007 1:12:43 P.M. Central Daylight Time, [EMAIL PROTECTED] writes: Using a sector number of x'00' effectively disabled RPS on devices that did care. Not true. It forces the controller to position the track at index point, the very beginning of the track. A sector value of X'FF' is the only value that causes the controller to bypass setting an angular position. Of course, this could also be bypassed by not having a set sector command or a locate record command with a sector value of X'FF', but then you defeat the original intended purpose of RPS. Bill Fairchild Plainfield, IL ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html .. For: [EMAIL PROTECTED] -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Track size and maximum single volume data set size
3375 was CKD Tom Marchant wrote: On Fri, 13 Jul 2007 08:13:42 -0500, Staller, Allan wrote: Not true. 3370 and 3375 were supported (for a while). Never caught on in the MVS Markeplace and were dropped Didn't MVS require CKD emulation to use them? -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: ISPF list data set attributes?
Shmuel Metz (Seymour J.) wrote: In [EMAIL PROTECTED], on 06/01/2007 at 12:15 PM, Rick Fochtman [EMAIL PROTECTED] said: IIRC, the actual count of print hammers on the 1403-N1 was 132. Perhaps I was thinking of the 1443. One of them definitely supported 144 columns. I'm not aware of any IBM printer for which the limit was 150. 144 columns was an option on the 1443. 3211 had a limit of 150. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: ISAM and/or self-modifying channel programs
Wouldn't a regular IPL sequence qualify as a self-modifying channel program? Typically: Read more CCWs from the IPL device then TIC to those CCWs (IBM Mainframe Discussion List) wrote: In a message dated 3/8/2007 9:42:12 P.M. Central Standard Time, [EMAIL PROTECTED] writes: In my book, that's not *really* a self-modifying channel program. (It's just using the same data area in more than one CCW. I know of at least one ISV product in use today that writes from a buffer and later in that same channel program, uses the same buffer for input.) I agree. To me, a self-modifying channel program is one that alters any part of any of its CCWs, any control fields that they references (e.g., locate record's 16 parameter bytes), or any indirect address list used by any of its CCWs. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: IBM S/360 series operating systems history
VM has always shipped with '3CARD LOADER S2' With the advent of XA the number of cards increased to 5. (IBM Mainframe Discussion List) wrote: In a message dated 3/8/2007 2:05:22 P.M. Central Standard Time, _patrick.okeefe @ WAMU.NET_ (mailto:[EMAIL PROTECTED]) writes: I remember 3 different BPSloaders - 3-card, 7-card, and 12-card versions. There very well could have been a 6-card loader, too. I may have had a brain check. I thought it was 6, but it must have been 7. 3 seems like too few. And it was all too many decades ago. Bill Fairchild Plainfield, IL Criticism and dissent are the indispensable antidote to major delusions. [Alan Barth, 1951; The Loyalty of Free Men] BRBRBR**BR AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html .. For: [EMAIL PROTECTED] -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: S0C1 with ILC 6
McKown, John wrote: Then what happens if the instruction starts at address x'00010FE' and address x'0002000' is either (1) fetch protected in a different key than the PSW key (assuming PSW key != 0) or (2) it has never been getmained and so is not a valid virtual address? That would have to be an S0C4 on instruction fetch. But wouldn't that have an ILC of 0? ILC is 4 - the 41xx at 10FE is not part of the failing fetch. ILC must be known to cause the S0C4 Old prog psw is 2002 -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Suppressing PER messages
Is there a way to suppress the message 'Command Complete' issued by a PER CMD? Example Issue 'PER DIAG 58 PRINTER CMD DUMP 0.20;BASE3' sends 'Command Complete' to the console for each DIAG 58 requiring a clear key between each full screen display. This message in not affected by SET EMSG or SET IMSG Is there any way to suppress the message ? If not why not? -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Suppressing PER messages
NOTERM applies only to the output of the PER and is implied by PRINTER The message in question is from the subsequent CMD when the PER occurs Binyamin Dissen wrote: On Wed, 1 Nov 2006 12:34:50 -0600 Chris Langford [EMAIL PROTECTED] wrote: :Is there a way to suppress the message 'Command Complete' issued by a :PER CMD? :Example : Issue 'PER DIAG 58 PRINTER CMD DUMP 0.20;BASE3' : sends 'Command Complete' to the console for each DIAG 58 requiring a :clear key : between each full screen display. : This message in not affected by SET EMSG or SET IMSG :Is there any way to suppress the message ? If not why not? What about TRACE with NOTERM? -- Binyamin Dissen [EMAIL PROTECTED] http://www.dissensoftware.com Director, Dissen Software, Bar Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html .. For: [EMAIL PROTECTED] -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Suppressing PER messages
Bingo but not as suggested MODIFY COMMAND PER ... gives HCPZPM770E MODIFY is not valid for command PER But MODIFY COMMAND DUMP SILENTLY then PER DIAG 58 PRINTER CMD SILENTLY DUMP 0.20;BASE3 Gives desired results Thank You Tom Schmidt wrote: Have you explored the MODIFY COMMAND x SILENTLY command yet? You have to modify the command (via the MODIFY COMMAND command) and then issue your 'PER DIAG 58 PRINTER CMD DUMP 0.20;BASE3' command as: 'SILENTLY PER DIAG 58 PRINTER CMD DUMP 0.20;BASE3' instead. It is in the z/VM 5.1 CP Commands and Utilities documentation. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: WHY IS JCL ALLERGIC TO LOWER CASE?
Gerhard Postpischil wrote: Chris Langford wrote: 1403 printers had chains, 3211 had trains. Both had a FOLD option to upper case on the fly. If you care to look at the IBM archive at http://www-03.ibm.com/ibm/history/exhibits/attic3/attic3_024.html you will find a chain under the heading IBM 1403 Printer Train. At my installations we used the terms interchangeably (note that the slugs in the cartridge may be considered as cars running on a track, following the index slug, resembling a train?) See: http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP1401.html For a description of the 1403 chain On the 3211 the slugs were not connected thus the 'train' I don't remember the FOLD option being a printer feature; it was implemented via a CCW, and could have been performed in the control unit. I never had access to a 3203 or 3211; Load UCS and fold (CCW Opcode x'F3') - Load UCS no fold (CCW Opcode x'FB') when the monthly maintenance on our 1403 got to $700, we upgraded to Documation printers that uses bands. Gerhard Postpischil Bradford, VT -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Chains/Trains was Re: WHY IS JCL ALLERGIC TO LOWER CASE?
Correction According to http://www.research.ibm.com/journal/rd/255/ibmrd2505ZJ.pdf While early 1403 models had 'chains', 1403 Models 3 and N1 has 'trains' -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: WHY IS JCL ALLERGIC TO LOWER CASE?
Gerhard Postpischil wrote: Tom Marchant wrote: It wasn't so much the cost of the print trains, but the lower case only ones were faster. ITYM upper case only. The AN and HN trains had four repetitions of the (upper case) alphabet, whereas the PN train had three, and the TN train had two. I never used AN or SN, and don't really remember what they had. We also had a custom train made according to American Library Association specifications, that had even more special characters, and was really slow (I added it as a UN train g.). Gerhard Postpischil Bradford, VT 1403 printers had chains, 3211 had trains. Both had a FOLD option to upper case on the fly. I don't think I had lower case fingers till the 3270s came out. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Binder REP Cards (Was: What's the linkage editor really wants?)
However CMS LOAD rejects a SYM card as invalid. Assembler generates it, LOAD hiccups. Chris Mason wrote: Shmuel, Check this out. It appears to be CMS HELP for the LOAD command. It includes a description of the REP card but also a VER card. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: capacity of largest drive
But, all disk CCws also have a module number in the seek address that is now unused. Only device I know of that used it was the 'Noodle Snatcher' 2321? which was supported by MVT. So isn't it just a matter of reinserting code to increment the module number ?? :))) Chris Bruce Black wrote: The DCE (UCB DASD Class Extension) has two different halfword fields indicating capacity. It would appear that the next model larger in capacity than the model 54 with 65520 cylinders will push the envelope off its edge. The problem is not the DCE, it is the CCWs. In all disk CCWs, the cylinder number is a half-word, 2 bytes, which has a maximum value of 65535 as an unsigned value (X''). This is why the large disk support was in two phases. There were many places in IBM and other code which did signed arithmetic on the cylinder number. The largest positive signed half-word value is 32767 (X'7FFF') and IBM chose to support 32760 as the largest cylinder number in the first phase. Both IBM and ISVs had to make some changes to be sure they could handle values that large, but at least the arithmetic did not have to change. The second phase, up to 65520 cylinders, required IBM and others to review every place that cylinder numbers were manipulated and insure that unsigned arithmetic was used. This was undoubtedly a more extensive change. Disk hardware has always treated the cylinder number as unsigned, so no CCW processing changes were needed there. but IBM can't increase the size again without changing CCW protocols to specify larger cylinder numbers. A number of schemes have been tossed around, but all would require every piece of IBM and ISV code which builds or scans disk CCWs to be modified. I haven't heard any recent talk about doing so, so perhaps it is a dead idea. The changes on the z990 to support multiple channel subsystems is beginning to address the maximum number of disk device limitations, so perhaps this is IBM's solution to the problem. -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Highly used programs: any better replacements out there? IDCAMS, IEFBR14
Bill Fairchild wrote: In a message dated 7/13/2005 8:35:47 P.M. Central Daylight Time, [EMAIL PROTECTED] writes: Wouldn't XR R15,R15 have been more efficient? No. Yes. On what processor? Even in the S/360 days the answer would depend on the box. Likewise SR versus SLR vs LA. Right on, Shmuel. I learned Assembler's op codes on a S/360 model 30. I still prefer to do a SLR to clear a register over SR and XR because SLR was the fastest way on the model 30. But on today's big-end processors, the time to execute any one given instruction depends on 853 variables, give or take πr². But the real bottom line is that the difference in how long it takes any of the different possible ways is vanishingly minute, and only of practical value if that instruction must be executed thousands of times per second. The amount of time it takes a programmer to think about which of three different instructions to use costs millions of times more than the cost recovered by executing the optimal instruction. However, even though it is not of much value, it is certainly of interest. If you really want to know how to speed instructions up, you must be prepared to read lots of highly arcane technical papers on instruction processing units, pipelines, instruction caches, translation lookaside buffers, data caches, bus width, look-ahead instruction preprocessing, multiple processor serialization effects, instruction predecessor relationships, et alia. That's where the 853 variables comes from. The model 30 had a simple set of numbers with no variables. Load Address was something like 19 microseconds no matter what. Not quite, IIRC if the index register is not zero then add a few microseconds for any instruction with index reg. Bill Fairchild -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html .. For: [EMAIL PROTECTED] -- Chris Langford, Cestrian Software: Consulting services for: VM, VSE, MVS, z/VM, z/OS, OS/2, P/3x0 etc. z/FM - A toolbox for VM MVS at http://zfm.cestrian.com Deva Woodcrafting: Furniture creation, House remodeling, Wagon restoration etc. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
