On Wed, 24 Feb 2016 16:46:59 +0530, baby eklavya wrote: >Is there a different place where this concept is documented with more >details ? ..
Prefixing is documented in the Principles of Operation. Every processor has its own first page (actually two pages now). The reason is that there are several storage locations that the processor requires. For example, when an interrupt occurs, the PSW is saved in the OLD PSW location for that kind of interrupt. Then the PSW is loaded form the NEW PSW location for that kind of interrupt. There are six kinds of interrupt. Eventually, the Old PSW will be used to dispatch the program that was interrupted. >This feature is unique to the PSA area, and is accomplished >through a unique DAT manipulation technique called prefixing. I don't think of this as a "DAT manipulation technique". I think of DAT as the mechanism that converts a virtual address to a real address. Prefixing converts a real address to an absolute address. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
