IBM OS/390 User Manual

Table 41 (Page 2 of 2). ILC Migration Considerations

A phase containing one or more VS
COBOL II programs, with calls to or from
C/370

 1. Upgrade the C/370 source code, and

c o m p i l e   w i t h   O S / 3 9 0   C / C + + .

 2. Transfer the VS COBOL II object

code to OS/390.

 3. Link-edit the load module with

OS/390 Language Environment.

The Assembler distributed with OS/390 is the High Level Assembler for MVS &
VM & VSE (HLASM). Therefore, this is the same product as the high level
Assembler distributed with VSE/ESA. If you are using the old VSE Assembler,
you will first have to convert your assembler programs to HLASM. You can use
HLASM on VSE/ESA version 1 release 2 or later.

To use HLASM with LE/VSE or OS/390 Language Environment, you need to code
the applications with the assembler macros provided with LE/VSE or OS/390
Language Environment. You must also ensure that the assembler programs
adhere to certain conventions for register and storage usage, for condition
handling and accessing input parameters. For example, you should avoid using
register 12 because Language Environment uses that register when establishing
the execution environment for the application.

For more information see the chapter on assembler considerations and
Language Environment macros in the 

OS/390 Language Environment

Programming Guide. You should also read Chapter 13, “Assembler” on
page 267.

This section discusses some issues you should consider when migrating from
LE/VSE-conforming languages and LE/VSE.

The items discussed here are only some of those you should consider; they are
items for which the behavior in OS/390 Language Environment is different from
their behavior in LE/VSE. You should also read the migration guides for OS/390
Language Environment, and for your release of LE/VSE.

In general the run-time options with OS/390 Language Environment have the
same usage and the same default values as the corresponding options in
LE/VSE.

However, there are some considerations of which you should be aware when
planning your migration.

The following options have different behavior in OS/390 Language Environment
to their behavior in LE/VSE.

Chapter 17. Language Environment (LE)