On Fri, 8 Nov 2019 14:15:11 -0700, Bob Raicer wrote: >Well, the statement from Peter Relson (and others) which is >essentially: >---------- >LA R1,1 is exactly equivalent to LA R1,1(0). Just look at the >generated object code. >---------- >is not totally true. It all depends upon which USINGs are in effect. > >Take a peek at the following example (admittedly a bit unusual, but >perfectly legitimate). > > Loc Object Code Addr1 Addr2 Stmt Source Statement >00000000 00000000 00000008 1 EXAMPLE CSECT , > R:9 00000000 2 USING 0,9 >00000000 4120 9100 00000100 3 LA 2,256 >00000004 4120 0100 00000100 4 LA 2,256(,0) > 5 END ,
Yes, your example shows that the two forms can be different, but, 1. I can't think of a reason to ever code USING 0,r. Registers are a scarce resource. 2. The code snippet is missing an instruction to clear register 9. -- Tom Marchant
