pTAL Reference Manual (H06.08+)

Built-In Routines

HP pTAL Reference Manual—523746-006

15-31

$CHECKSUM

$CHECKSUM returns the checksum of data.

checksum input,output

uINT:variable

the initial value (“seed” value) of the checksum. When $CHECKSUM

completes, checksum holds the final checksum. checksum must be an INT

variable. It cannot be a STRING, UNSIGNED, or USE variable or a bit field.

bufferaddr input

EXTADDR:value

the address of the first 16-bit word to include in the checksum.

wordcount input

uINT:value

the number of 16-bit words to include in the checksum.

$CHECKSUM accumulates the checksum by performing an exclusive-or operation on

the accumulated checksum and wordcount successive 16-bit words, starting at

bufferaddr. When $CHECKSUM completes, checksum holds the accumulated

checksum and bufferaddr is unchanged.

pTAL privileged procedure No

Can be executed only by privileged procedures No

Sets condition code No

Sets $CARRY No

Sets $OVERFLOW No

(

checksum

bufferaddr

) ;

VST613.vsd

wordcount

$CHECKSUM