pTAL Conversion Guide

Equivalenced Variables
pTAL Conversion Guide—527302-002
12-4
Declaring Equivalenced Nonstructures
Declaring Equivalenced Nonstructures
pTAL equivalenced declarations for nonstructure variables include two features that
are not supported by TAL:
•
Equivalenced arrays
•
An optional REFALIGNED clause on an equivalenced pointer
VOLATILE
specifies that the value of this variable must be maintained in memory, not in a
register. Each reference to a VOLATILE data item causes the data item to be read
or written to memory even when code is optimized. Based on the order of reads
and writes in the source code, VOLATILE also causes that precise order of
memory references to be preserved, again, when code is optimized.
type
If referral is present, must be STRING or INT; otherwise, type is any data
type except UNSIGNED.
identifier
is the identifier of the equivalenced variable to be made equivalent to previous-
identifier.
VOLATILE
identifier
,
[
=
type
previous-identifier
+
-
offset
index
]
;
( referral )
VST629.vsd