I can build the function to check if the bit is turned on then if it is subtract the value. But in Perl I can negate a value and hoped that KiXtart supported that as well.
Work around:
;if $SPval & 128
; $SPval = $SPval - 128
;endif
In Perl I can:
$SPval = $SPval & ~128
where "~" is a bitwise negation operator. Off to the "Suggestions" forum. 
