Tom, I beg to disagree with you. Here is a plain-text paste of the section of the latest PoOPs describing the LOAD instruction (page 7-213, 585 of 1496 in the PDF of the document):
Register-and-storage formats: L R1,D2(X2,B2) [RX-a] '58' R1 X2 B2 D2 0 8 12 16 20 31 LY R1,D2(X2,B2) [RXY-a] 'E3' R1 X2 B2 DL2 DH2 '58' 0 8 12 16 20 32 40 47 LG R1,D2(X2,B2) [RXY-a] 'E3' R1 X2 B2 DL2 DH2 '04' 0 8 12 16 20 32 40 47 LGF R1,D2(X2,B2) [RXY-a] 'E3' R1 X2 B2 DL2 DH2 '14' 0 8 12 16 20 32 40 47 Note that LY is E358 and LG is E304. And for confirmation, from Appendix B, figure B-1, page B-11 (aligning spaces added, so I hope the alignment survives the email transmission): LOAD (32) L RX-a A B2 58 7-213 LOAD (32) LR RR 18 7-213 LOAD (32) LY RXY-a LD A B2 E358 7-213 LOAD (64) LG RXY-a N A B2 E304 7-213 LOAD (64) LGR RRE N B904 7-213 LOAD (64 <- 32) LGF RXY-a N A B2 E314 7-213 LOAD (64 <- 32) LGFR RRE N B914 7-213 The last column is the page number, and the next-to-last column is the operation code. HTH Peter -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Tom Marchant Sent: Friday, August 05, 2011 11:10 PM To: [email protected] Subject: Re: Suffix of 64 bit instructions On Fri, 5 Aug 2011 18:52:41 -0400, Farley, Peter wrote: >LY instruction format from the Principles of Operations looks like: > >'E3' R1 X2 B2 DL2 DH2 '58' You misread the chart. the above is LG, not LY >STY instruction format from the Principles of Operations looks like: > >'E3' R1 X2 B2 DL2 DH2 '50' Again, the above is STG, not STY >Those are not 64-bit instructions, but "long displacement" instructions that >have a 20-bit displacement rather then the 12-bits of the regular old L and ST >instructions of the 360 era. These instructions are 6 bytes long (48 bits). > >The x'58' at the end of the LY instruction is the second byte of the operation >code (IOW, 16-bit opcode in first and last bytes, opcode value 'E358'). Ditto >for the STY instruction (opcode value 'E350'). STG, not STY; LG, not LY >Take a look at the various instruction formats listed in the >PoOPs manual in chapter 5, section title "Instruction Formats". >Some opcodes are one-byte long, some are two bytes one after >the other, some are two separate bytes, some are a byte and a >nibble (a half-byte). To the OP: Peter's response is basically correct. You should indeed read the POO. The chapter that he cited is a good one to study. -- Tom Marchant >> -----Original Message----- >> From: IBM Mainframe Discussion List [mailto:[email protected]] On >> Behalf Of Micheal Butz >> Sent: Friday, August 05, 2011 6:23 PM >> To: [email protected] >> Subject: Suffix of 64 bit instructions >> >> Hi >> A number of the 64 bit instruction >> Seem to have a constant in the last >> Byte e.g. LG. 58 >> STG 50 would anyone know the siginifcance of this -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- 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
