"A PC can execute what might have taken many instructions before" is true in the same sense that it is true for BAL: one instruction that you code goes off and does a bunch of stuff elsewhere, saving you having to code all those instructions.
It is also true in the sense that a PC can do in one instruction what would have taken a whole series of instructions before: switching AMODE, switching problem state, and branching. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Peter Relson Sent: Friday, August 30, 2019 5:25 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Assembler :- PC Instruction <snip> >From what I understood of the PC instruction: with 1 instruction you can now execute a 'function' that might have taken pages of assembler instructions before. </snip> I'm not sure where this thought comes from. The PC instruction is not magic. It does not execute a "function" beyond the function of the instruction itself. It passes control somewhere, may change state, may create an entry on the linkage stack. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
