> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Greg Price > Sent: Wednesday, June 18, 2008 9:03 AM > To: IBM-MAIN@BAMA.UA.EDU > Subject: LRVH instruction - misnamed or BAD? > > LRVH - Load Reversed (Halfword) > > So it should load a reversed halfward, right? > > Well, sure, it swaps the byte order (compared to their order > in storage) > and puts them in register bits 48->63, **BUT** it leaves bits 0->47 > UNCHANGED. > > Now, that last part is not what LH does, is it? > > In my book, that's an INSERT, not a LOAD. I think it should have > zeroed bits just like LH does. I think the LOAD (as I envisage it) > function is more useful than the INSERT function (as it is > implemented). > > Am I right or am I right? (They are the only possibilities, > aren't they?) > > Cheers, > Greg
I agree. I guess to really make this do what I would generally want, I'd need to do something like: LRVH R0,INTEL_HALFWORD SLL R0,16 SRA R0,16 That would propagate the sign bit correctly. That's for only using the 32 bit register. For using 64 bit, I'd replace the 16 with 48. -- John McKown Senior Systems Programmer HealthMarkets Keeping the Promise of Affordable Coverage Administrative Services Group Information Technology The information contained in this e-mail message may be privileged and/or confidential. It is for intended addressee(s) only. If you are not the intended recipient, you are hereby notified that any disclosure, reproduction, distribution or other use of this communication is strictly prohibited and could, in certain circumstances, be a criminal offense. If you have received this e-mail in error, please notify the sender by reply and delete this message without copying or disclosing it. ---------------------------------------------------------------------- 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