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The selection of a particular option of MVS may require redesigning the
application programs. In addition, a program logic change may also be forced by
attempting to simulate a VSE function under MVS. Examples of these possibilities
include multitasking, interrupt handling, and communication region accessing.
The input and output components of the linkage editors, the job control
language, and linkage edit control statements necessary to build program
structures are discussed in the publication
DFSMS/MVS Program Management
,
SC26-4916.
VSE assembler language programs that are changed to MVS must add an
initialization routine to meet MVS requirements. You should establish a standard
for the entire installation that can be simply inserted into the assembler
language source member before it is recompiled under MVS. For additional
information on the MVS services and macro coding details, refer to the following
publication:
•
OS/390 MVS Programming: Assembler Services Reference
, GC28-1910.
For Data Management programming macro information, refer to:
•
DFSMS/MVS Using Data Sets
, SC26-4922.
•
DFSMS/MVS Macro Instructions For Data Sets
, SC26-4913.
Important
The macro functions and parameters described in this text may not be totally
up-to-date. Macro facilities change over time. New macros and macro
parameters become available with new releases of products. Therefore, you
should always reference the appropriate macro manuals (listed above) for
exact macro functions and applicable parameters. (Even though some
macros may not be up-to-date, the techniques illustrated here should still be
applicable.)
The next section highlights the services provided by the MVS supervisor and
relates them to comparable ones provided by VSE. Information on VSAM
macros is found in the section 13.2.5, “VSAM Macros” on page 290. Data
Management macro comparisons are addressed in the section 13.2.6, “Data
Management Macros” on page 292.
13.2.1 System Interface and Macros
The functions of the VSE system interfaces and macros and their MVS
equivalents are discussed in the following text.
MVS Register Conventions
Application program use of general purpose registers in MVS is restricted to
registers 2 through 12. (Registers 0, 1, 13, 14 and 15 are used for special
purposes by MVS - see next sections.) If VSE programs use other than
registers 2-12 for application purposes, program register assignments may
have to be changed.
268 VSE to OS/390 Migration Workbook