At 21:13 +0100 on 12/21/2006, Lindy Mayfield wrote about Question
about SVC 109:
Can someone please tell me if I have gotten this right? (:
SVC's are numbered from 0 to 255.
From 0 to 199 are reserved for IBM use.
SVC 109 is basically an SVC that can call an SVC from 0 to 255, and
again IBM has reserved 0 - 199 for their own use. This in essence
extends the range of SVC's from 256 to 256*2.
SVC's called by SVS 109 can only be type-4 SVC's.
Why not type-3? Nowdays, I cannot see any differences between
type-3 and type-4. Am I missing something?
A Type3-SVC has a Module name of IGC00xxx (for SVC XXX with the 3rd X
being signed [ie: A-I or X'C0']). A Type4-SVC has the Module Name of
IGCyyxxx (XXX is the SVC Number and signed as above while the YY is
the module number - 00 is the base module called via "SVC XXX" while
any YY not equal to 00 is called by another IGCyyxxx Module). Most
NEW SVCs are single Module and thus in theory Type3 but most old SVCs
(Such as OPEN, CLOSE, and others), are still multi-Module and thus
Type4.
SVC 109 SVCs are all Type4 (even if only one module) but are named
IGXyyxxx. You call "SVC 109" with yyxxx in R15. Thus if I load
F'15245' into R15 and issue a SVC 109 it will link to IGX15245. Note
that there are two other SVCs that do the same thing for Type1 and
Type2 Extended SVCs.
thanks so much.
Lindy
----------------------------------------------------------------------
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
