pTAL Reference Manual (H06.03+)

Built-In Routines
HP pTAL Reference Manual—523746-005
15-3
Expressions as Parameters
Expressions as Parameters
Many built-in routines accept expressions as parameters (see their individual syntax
descriptions). If a parameter of a built-in routine is an expression:
•
The value of the expression can be any data type except STRING or UNSIGNED.
•
Except in INT and INT(32) expressions, all operands must be of the same data
type.
•
An INT expression can include STRING, INT, and UNSIGNED(1-16) operands.
The system treats STRING and UNSIGNED(1-16) operands as if they were 16-bit
values; that is, the system:
°
Places a STRING operand in the right byte of a word and sets the left byte to
0.
°
Places an UNSIGNED(1-16) operand in the right bits of a word and sets the
unused left bits to 0.
•
An INT(32) expression can include INT(32) and UNSIGNED(17-31) operands.
The system treats UNSIGNED(17-31) operands as if they were 32-bit values.
Before evaluating the expression, the system places an UNSIGNED(17-31)
operand in the right bits of a doubleword and sets the unused left bits to 0.
•
The built-in routine, not the expression or its data type, determines whether the
value of the parameter is signed or unsigned:
°
Built-in routines that expect signed arguments treat unsigned expressions as if
they were signed.
°
Built-in routines that expect unsigned arguments treat signed expressions as if
they were unsigned.
Example 15-2. Built-In Routine With Address Output Parameter
STRING .s[0:99];
$BUILT_IN_2(@s); ! ERROR: s has no address container
! in which to store a new address