pTAL Reference Manual (G06.24+, H06.09+, J06.03+)

type

is any data type except UNSIGNED. The data type determines how much data the simple

pointer can access at a time—a byte, word, doubleword, or quadrupleword.

Indirection

., .EXT, .EXT32, .EXT64, .SG, and .SGX are indirection symbols (see Table 14 (page 41)).

identifier

is the identifier of the new simple pointer.

REFALIGNED

specifies the base alignment of the structures that the structure pointer will reference.

references a structure that might not be well-aligned.

indicates that the base of the structure and the fields in the structure are well aligned in memory

previous-identifier

is the identifier of a simple variable, array, substructure, or pointer previously declared in the

same structure. No index is allowed with this identifier.

Example 99 Simple Pointer Redefinition

STRUCT my_struct;

BEGIN

STRING var[0:5]; ! Simple variable

STRING .EXT ext_pointer = var; ! Redefine var as simple

! pointer, ext_pointer

END;

Structure Pointer

A structure pointer redefinition associates a new structure pointer with a previous item at the same

BEGIN-END level of a structure.

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

Declaring Redefinitions 159