pTAL Conversion Guide

Expressions

pTAL Conversion Guide—527302-002

13-12

Changing the Location of the Data

Figure 13-1 on page 13-11 and Figure 13-2 on page 13-12 show that changing the

data type of a variable from INT to STRING can affect whether the address stored in

the result pointer, p, is an even-byte or odd-byte address and, therefore, how such a

change could cause your program to generate different results for TNS and native

processes.

Changing the Location of the Data

Figure 13-3 on page 13-13 is the same as Figure 13-1 on page 13-11 except that y

specifies .EXT. The IF statement, therefore, compares x to y on a byte-by-byte basis.

Because the first (upper) bytes of x and y are equal, the comparison continues to the

second byte of each variable. Because the second byte of x is “B”, but the second byte

of y is “C”, the conditional expression is false. In Figure 13-3, therefore, the IF

statement stores in p the address of the second (lower) byte of x.

Figure 13-2. Ending Address After Comparing Strings of Data Type STRING and

INT

PROC p;

BEGIN

INT x[0:1] := ["AB","CD"];

STRING y[0:1] := ["A", "C"];

STRING .p;

INT q;

IF x = y FOR 1 WORDS -> @p THEN ... ;

q := p; ! q is assigned "AB" on a TNS processor

! q is assigned "BC" on a TNS/R processor

END;

ABCD AC

User Data Segment

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