TAL Programmer's Guide

Accessing the User Code Segment

Managing Addressing

096254 Tandem Computers Incorporated B–9

Accessing the User

Code Segment

You can access the user code segment by storing a 32-bit byte address in an extended

pointer. To build the address, use:

The $DBLL standard function, which returns an INT(32) value from two INT

values. The first INT value becomes the upper half of the INT(32) value, and the

second value becomes the lower half.

An unsigned bit-shift operation ('<<' 1), which converts a word address to a byte

address.

Initializing Simple Pointers You can initialize an extended simple pointer with a 32-bit byte address for read-only

access. The address can point to the seventh word or fourteenth byte of the current

user code segment:

INT .EXT ext_ptr := ($DBLL (3, 7)) '<<' 1; !Declare and

! initialize extended simple

! pointer with 32-bit byte

! address in user code segment

Assigning Addresses to

Simple Pointers

You can assign an address for read-only access in the current user code segment as

follows:

INT .EXT ext_ptr; !Declare extended simple

! pointer

@ext_ptr := ($DBLL (3, 7)) '<<' 1;

!Assign current code

! segment address