limiting to "no less than" zero

[Heckler]

Here is my test code and the debug results below...

 DEFINE DEBUG_REGG PORTA        'set debug port to porta
 DEFINE DEBUG_BIT 0             'use pin a0 of porta for debug
 DEFINE DEBUG_BAUD 2400         'set baud rate to 2400
 DEFINE DEBUG_MODE 0            'communicate in true mode
valA var byte
valB var byte
resultA var byte
resultB var byte
resultC var byte
resultD var byte
   Carry var bit
   vala=51
   valb=50

resulta=vala-valb
Carry = STATUS.0
debug "resultA : 51-50=",dec resulta," Carry=",dec carry,13,10

resultb=valb-vala
Carry = STATUS.0
debug "resultB : 50-51=",dec resultb," Carry=",dec carry,13,10

resultC=vala+valb
Carry = STATUS.0
debug "resultC : 51+50=",dec resultc," Carry=",dec carry,13,10

vala=55
valb=201

resultD=vala+valb
Carry = STATUS.0
debug "resultD : 55+201=",dec resultd," Carry=",dec carry,13,10
end

and the Debug results...


resultA : 51-50=1 Carry=1
resultB : 50-51=255 Carry=0
resultC : 51+50=101 Carry=0
resultD : 55+201=0 Carry=1