pTAL Reference Manual (H06.03+)

Equivalenced Variables
HP pTAL Reference Manual—523746-005
11-29
Equivalenced Structure Pointer
.
.EXT
.SG
.SGX
are indirection symbols (see Table 2-7 on page 2-7).
identifier
is the identifier of a structure pointer to be made equivalent to 'SG'.
referral
is the identifier of a previously declared structure or structure pointer that is to
provide the layout for identifier.
'SG'
denotes a 16-bit system global address.
index
is an INT constant that specifies the offset of the element in previous-ident to
which the equivalenced pointer or variable refers. Specify index only with direct
variables. index must end on a word (16-bit) boundary.
+
-
is the word or byte offset, relative to the base of previous-ident, where the
equivalenced variable is placed. For example, if a and b are declared:
INT a[0:9];
INT b = a+5
then b is placed at a[5].
offset
an equivalent INT values in the range 0 through 63.
Table 10-1 on page 10-6 describes the kind of addresses a structure pointer can
contain depending on the STRING or INT attribute and addressing symbol.
Example 11-18. Equivalenced Structure Pointer Declaration
STRUCT .some_struct;
BEGIN
INT a;
INT b[0:5];
END;
INT .struct_ptr (some_struct) = 'SG' + 30;