CICS and Assembler

[billl....@gmail.com]

The example program found at ===> http://www.mainframes360.com/2010/11/learning-assembler-language.html, was written for Batch and is non-reentrant. Of course, the DCB must be removed to execute in CICS as a "CALLED" sub-program. The easiest method to run in CICS is to pass reentrant storage (this is a necessity in a Threadsafe/OpenAPI environment) from the caller as a parameter. If this were running in Batch, using the CICS DFHAFCD Macro (expands into 3 "load" instructions) can tell you (see below) whether the run-environment is CICS or Batch. With that, if Batch, then the storage allocated can be non-reentrant and defined to the program itself (known as program-storage) or always pass the reentrant storage as a parameter from the Caller and then it doesn't matter.

 

         DFHAFCD TYPE=LOCATE    R15 is the default

         LTR   15,15                             Valid address?

         BZ      BATCH                         No,  Batch environment

         CLC   =CL3'AFC',0(15)           Target literal found?

         BNE   BATCH                          No,  Batch environment

 

HTH....

 

Regards,

 

Bill (Grumpy Old Dinosaur)

[Quasar Chunawala]

Hi Bill,

Nice insight about DFHAFCD. I realize, that if the caller always passes re-entrant storage, then it really doesn't matter.

Apart from a programming course on MVS Assembler, I haven't done any Assembler. So, let me ask this - 

One - Can re-entrant storage be equated to LINKAGE in COBOL?

Two - I have a copy of Hank Murphy's book on Assembler. What are the other good books on the subject?

Thanks in advance,

Quasar

http://in.linkedin.com/pub/quasar-chunawala/20/164/133/

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[Quasar Chunawala]

Bill - Here's the cover of the book, "Assembler for COBOL programmers". I think, this should evoke some good memories!

Quasar

http://in.linkedin.com/pub/quasar-chunawala/20/164/133/