pTAL Reference Manual (H06.08+)

Built-In Routines

HP pTAL Reference Manual—523746-006

15-30

$CARRY

$CARRY returns a value that indicates whether an arithmetic carry occurred during

certain arithmetic operations or during execution of a SCAN or RSCAN statement.

The value returned by $CARRY is based on instructions emitted by the compiler that

determine whether a carry occurred. $CARRY returns -1 if a carry occurred, 0

otherwise.

Procedures cannot return $CARRY.

You can test $CARRY only after one of the following statements:

•

An assignment statement in which the final operator executed in the expression on

the right side of the assignment is one of the following:

Signed integer add, subtract, or negate

Unsigned integer add, subtract, or negate

•

A SCAN or RSCAN statement.

$CARRY cannot be an actual parameter. If it is important to pass the value of $CARRY

to a procedure, use code similar to that in Example 15-17 on page 15-30.

pTAL privileged procedure No

Can be executed only by privileged procedures No

Sets condition code No

Sets $CARRY No

Sets $OVERFLOW No

Example 15-17. $CARRY Routine

INT a, carry_flag;

carry_flag := 0;

a := a + 1;

IF $CARRY THEN carry_flag := 1;

CALL p1(carry_flag, .... );

VST076.vsd

$CARRY