Technical data

RLO, CC 0/CC 1 In connection with some of the special functions, errors specific to the
special function affect the condition codes CC 0/CC 1.
If an error occurs during the processing of these special functions, the
RLO is normally set (RLO = 1). When using these special functions,
you can use a JC operation (conditional jump) in your STEP 5
program to evaluate the RLO and to react to an error.
The processing of some special functions also affects the condition
codes CC 0 and CC 1. In your STEP 5 program, you can scan these
condition codes with comparison operations and once again react to
an error.
The following descriptions of the individual special function OBs
indicate which of these reactions apply to the particular special
function OB.
Note
Calling a special function OB with the operation JC OB > 39 or
JU OB > 39 is not a "genuine" block change, but is handled like a
STEP 5 operation without a block operand.
No interrupts are
inserted (when "interrupts at block boundaries" is set).
Special functions with
pseudo operation
boundaries
Some of the special functions are carried out in several steps and
contain what are known as pseudo operation boundaries.
This means that the special function is executed in several steps. If an
error (e.g. ZYK) or an interrupt (e.g. time or process interrupt at
operation boundaries) occurs during the execution of a step, the
appropriate organization block is inserted at the end of this step at the
pseudo operation boundary.
The special functions containing pseudo operation boundaries are
marked in the overview of the integrated special functions.
Introduction
CPU 928B Programming Guide
6 - 10 C79000-B8576-C898-01