On Thu, 29 Aug 2019 04:22:02 +0000, Jon Perryman wrote: >The PC instruction is a replacement for SVC. Both instructions exist >solely to run authorized programs in other address spaces.
No. The SVC instruction, as implemented by OS/360 and its descendants, exists to provide a service that requires execution in Supervisor state. The concepts of address spaces and authorized programs didn't exist until years later. While a common use case for PC routines is to execute code in another address space, that is not its only use case. Also, PC routines can be defined which receive control in problem state. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
