SHARE starts next week. If those on the list that attend SHARE, they could consider asking for this to be made a SHARE requirement. Otherwise, consider a HLASM RFE. In both cases, you can put forward your companies business justification for such changes. Sharuff
IBM Mainframe Assembler List <[email protected]> wrote on 28/02/2017 21:02:09: > From: Melvyn Maltz <[email protected]> > To: [email protected] > Date: 28/02/2017 21:02 > Subject: HLASM anomaly > Sent by: IBM Mainframe Assembler List <[email protected]> > > To restate what I'm asking for... > Now that we have 2 and 4-byte immediate values it would make sense > to allow both duplication factor and explicit length for these > Currently the instructions below would fail > AHI 1,2X'FF' > CFI 1,XL4'FF' > > Rather more contentious, I agree, is to imply an explicit length > of 1, 2, or 4 bytes to any immediate if there were no dup/explicit > already present > > So, CFI 1,C'9' generates X'000000F9' (yuk) > But if it were forced to have an explicit length it would be > interpreted as CL4'9'=X'F9404040' which is what you might expect ??? > Ok, I'll be shot down on that one, but I'll still submit it > > Steve Thomas---What does "immediate" mean to you ? > It means a DC-type constant of any form that is only constrained by > the length of the immediate according to the instruction > > Paul Gilmartin---How do you feel about AHI 1,X'00FFFF' > It exceeds the 2 byte limit and therefore invalid > If the explicit length were to be implemented, then it would > operate as XL2'00FFFF'=X'FFFF' > Yes, AHI 1,65535 is valid > In z390, AHI 1,X'00FFFF' is valid > In DeZhi, it generates but gives a warning > > Yes, it's an HLASM problem, some immediates are logical, some are > algebraic, it doesn't really matter how the immediate is generated > provided you get the result you intended > > John Ehrman---Immediates are not absolute > Sorry to disagree, 2X'FF' is just as absolute as X'FFFF' > I've always considered the result as definitive, not how we got there > > >>>consider AHI 0,(N)X'F' > By that stage in the Assembly, it would be known (I hope) that > AHI takes a 2-byte immediate, if the parsing of the DC-type > immediate exceeded that, it's an error...no acrobatics needed > > Chris Smith---Limits ot 16-bit signed...why examples of unsigned > Immediates can be logical or algebraic, compare CFI with CLFI > CLFI 1,-1 is a contradiction, but works ! > > John Dravnieks--- > Read above stuff, AHI 1,X'FFFF' does assemble with a warning > > Charles Mills--- > Sorry, but an immediate operand is a unit of storage, the fact that > it's embedded into an instruction is irrelevant > > I'm sure they'll be more flak flying, but I'll wait a few days for > the smoke to clear before I annoy Sharuff :-) > > Mel. > > Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
