Wouldn't RISBGZ R0,R1,62,63,2 be clearer than XR and SLDL? BTW, how do the timings compare on a z15?
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List [ASSEMBLER-LIST@LISTSERV.UGA.EDU] on behalf of Dave Clark [dlcl...@winsupplyinc.com] Sent: Friday, February 4, 2022 10:51 AM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU Subject: Re: Making Encoded Bits Human Readable David L Clark/it/crp/WinWholesale wrote on 02/04/2022 10:05:30 AM: > OK, let's examine this. I follow what lines 1 to 3 will do. But > it doesn't seem that line 4 will do what I need. The reason I am > confused is because the PoPs manual says that line 3, in this case, > will not change the content of R0, thus bits 28-31 are the same as > they were after line 2. In that case, how does line 4 get R0 bits > 28-29 into bit positions 30-31 where they need to be for line 5 to > work correctly? > > 1. LLGC R0,BYTE GET ENCODED BYTE (NEED BITS 24-27) > 2. SRL R0,4(0) SHIFT OUT RIGHTMOST 4 BITS > 3. SRLG R1,R0,2(0) SHIFT NEXT 2 BITS INTO R1 (R0 UNCHANGED) > 4. NILL R0,B'11' (CONFUSED, WHAT DOES THIS ACTUALLY DO?) > 5. AHI R0,C'1' ORIG. BITS 24-25 TO ZONED DECIMAL > 6. AHI R1,C'1' ORIG. BITS 26-27 TO ZONED DECIMAL And, yes, sorry, I treated all registers as 32-bit registers. Please adjust my comments accordingly. Thanks. Otherwise, I am currently using the following. LLC R0,RECBUF+108 NEED ONLY x'....XX..' PART SRDL R0,2+4 SHIFT OUT 6 BITS INTO R1 AHI R0,C'1' YIELD '1' TO '4' VALUE STC R0,CWORK FOR INTRASYSTEM SHROPT XR R0,R0 CLEAR REG FOR NEXT 2 BITS SLDL R0,2 SHIFT IN 2 BITS FROM R1 AHI R0,C'1' YIELD '1' TO '4' VALUE STC R0,CWORK+2 FOR INTERSYSTEM SHROPT Sincerely, Dave Clark -- Winsupply Group Services 3110 Kettering Boulevard Dayton, Ohio 45439 USA (937) 294-5331 ********************************************************************************************* This email message and any attachments is for use only by the named addressee(s) and may contain confidential, privileged and/or proprietary information. If you have received this message in error, please immediately notify the sender and delete and destroy the message and all copies. All unauthorized direct or indirect use or disclosure of this message is strictly prohibited. No right to confidentiality or privilege is waived or lost by any error in transmission. *********************************************************************************************
