From: "Paul Gilmartin" <paulgboul...@aim.com> Sent: Tuesday, 17 January 2012 7:33 AM
CDC 3600/3800 had a "Modify following instruction" instruction
The S/360 and subsequent machines have one like that also. In the case of MVC/CLC instructions :- stc 1,*+5 mvc a(0),b can be useful. EX does more than just "insert length" into SS instructions. The ability to OR in bits from the second byte of the subject instruction along with the content of the nominated register is probably rarely used in the case of SS instructions, but can be used to effect with RX instructions, where you might want to retain, say, the existing index field in the subject instruction, yet supply bits for the Register field of the subject instruction. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
