The D value is the offset of the literal from the relevant USING. the R values is the register from the USING and the X value is zero. This is very basic stuff.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Joe Monk <[email protected]> Sent: Saturday, October 23, 2021 8:18 PM To: [email protected] Subject: Re: Question about negative indexes OK then explain this: LH is an RX format instruction. What are the D, X and B values if the second operand is simply =H'-5'? Joe On Sat, Oct 23, 2021 at 6:49 PM Paul Gilmartin < [email protected]> wrote: > On Sat, 23 Oct 2021 18:36:54 -0500, Joe Monk wrote: > > >LH is an RX instruction. > > > >So, LH 3,=H'-5' would give an addressing exception, no? Because the second > >operand is treated as coming from storage? So that would be a negative > >address? > > > No. > > >If you said LH 3,0(=H'-5',2), that would give you ITEM+5? > > > You have a bad use-versus-mention conflation. The value of an > object is not the address of that object. > <https://secure-web.cisco.com/1Cc9X8nq783UC9J1JPtocjSP8oRNQtIjc0McoHQ7Dtf7hx47AuzGkTpG-MLS99sZ2RSeM7alOdb0fbxcnvPz9zzu5iw78nnOQugSG7Tm2wQoCt-9eq5LOH7gGHvFOMpqRiViExjFhgouWtXfbCXTA4gu3IkungoCFH75HGqCCjnec1oxWUWhGKkF2mDRQg_Mms53pAP_MxCJQjMoaawvOnxiz7qylbKGzn6PIcwHGVLERZt_z-3Q0NiRU--NkN-xN8WVn_PcJHhTiOkpWb3-jM9a-5JIY6Gr3TYiitQoi0gkKgYHDMSQlhbEmkvHC1CJiIu9ZarjELQqRPXuNMnnD6zUOtjEILP1vZMMzsZtjiKmONurOOAZbk5ds0kBocuSiUnVfRbrRqny4U3OSwLU6ud4BNlijUY0_j-XIdiqqZsqCUDUKwYGmV5zLFby1SY0E/https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FUse%25E2%2580%2593mention_distinction> > > > >On Sat, Oct 23, 2021 at 6:01 PM Bernd Oppolzer wrote: > >> > >> LA 2,ITEM+10 > >> LH 3,=H'-5' > >> LA 2,0(2,3) > >> > >> will put the address ITEM+5 in register 2, at least in AMODE 24/31? > >> > I agree. > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
