> -----Original Message-----
> From: IBM Mainframe Assembler List
> [mailto:ASSEMBLER-LIST@LISTSERV.UGA.EDU] On Behalf Of Robert
> A. Rosenberg
> Sent: Monday, June 04, 2012 11:33 PM
> To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
> Subject: Re: Base registers
>
<snip>
>
> By replacing the MYCSECT references with BYID+4 you can pick up some
> extra free addressability (at the expense of having the offsets
> non-zero based).
>
Back long ago, before I started writing "pure" or "reentrant" code, I would
always start my routines:
MYCSECT CSECT
USING *,R15
SAVE (14,12),,*
BAL R1,AROUND
SAVEAREA DC 18A(0)
ST R13,4(,R1)
ST R1,8(,R13)
LR R13,R1
DROP R15
USING SAVEAREA,R13
L R1,4(,R13)
L R1,20(,R1) RESTORE ORIGINAL R1
...
I don't do this any more, in most cases. Just to horrify some of you, I now
generally code HLASM enabled code, using all the CEExxx macros.
===
A reason that my manager did not like the above was that if the base register
points to the beginning of the CSECT, and you use the SAVE macro properly, you
can look at the storage pointed to by the base register to see the "eyecatcher"
of the program which abended. The SAVE would usually look something like:
SAVE (14,12),,'&SYSECT &SYSCLOCK'
And he always used base registers in reverse order: R12, R11, R10, and so on.
--
John McKown
Systems Engineer IV
IT
Administrative Services Group
HealthMarkets(r)
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(817) 255-3225 phone *
john.mck...@healthmarkets.com * www.HealthMarkets.com
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