$WW,1$$FG,2$Bt$FG$:	Bit Test
$FG,2$Bts$FG$:	Bit Test and Set to one
$FG,2$Btr$FG$:	Bit Test and Reset to zero
$FG,2$Btc$FG$:	Bit Test and Compliment (toggle)

$FG$These bit test operations are "atomic" meaning they won't be interrupted between the testing of the bit and the alteration.  This is important when multitasking.  With multiprocessing, you should "Lock" these operations.