>Most SVC's document which registers contain data to be used by the SVC >routine. Why would reissuing GETMAIN require the original callers R6? Only >R15-R1 are part of the API.
Most does not equal all. And none document internal-only interfaces. And what if new function is compatibly added (for example, when a bit in an existing interface register is "1" then it means that additional data is present, and to be used, in a new register)? It's very unlikely your exit would be able to "keep up" unless it made no assumptions at all about what status it must preserve. It might work "now" but later cause havoc to a customer's sytem. I know that I wouldn't want someone doing that to my system. >Of course, if one reissues the SVC (and it CAN be done), one must be sure to >issue it in the same state and key. Clearly you could do so if you disable SVC Screening itself. But in order to turn it back on you'd perhaps need to get control on the SVC return. That too seems to require doing unsupported things. And there are cases where the SVC issuer's address is important. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
