pTAL Conversion Guide

Statements

pTAL Conversion Guide—527302-002

15-7

Changing Implicit Pointers

TAL

You can change the implicit pointer of an indirect array or indirect structure.

pTAL

You cannot assign a value to the implicit pointer of an indirect array or indirect

structure. Because all native memory is addressable as a single continuous address

space, the native compiler does not necessarily allocate an implicit pointer for indirect

arrays and indirect structures.

CALL Statement

The CALL statement in pTAL is fully compatible with the CALL statement in TAL;

however, pTAL and TAL requirements for procedure declaration and passing

parameters are different.

TAL

A procedure’s formal and corresponding actual parameters match if each contains the

same number of bits.

Example 15-6. Implicit Pointer Change (TAL)

INT .a[0:99];

INT .b[0:99];

@a := @b; ! Change a to reference b's data

Example 15-7. Implicit Pointer Change (pTAL)

Invalid:

INT .a[0:9]; ! Indirect array

STRUCT .EXT s(s_tpl); ! Extended structure

@a := 0; ! ERROR: Attempt to store into implicit pointer

@s := 0; ! ERROR: Attempt to store into implicit pointer

Valid:

INT .a[0:9]; ! Indirect array

STRUCT .s(s_tpl); ! Indirect structure

INT .p; ! Pointer

@p := @a; ! p now points to data in a

@p := @s; ! p now points to data in s

@p := 0; ! Address in p is zero