Hi,
With M2 chips, only registers b0 to b3 are directly bit-addressable. Personally, in my programs I nearly always reserve b0 for "Global Flags" (8 off = bit0 to bit7), b1 as a "Temporary/Local Byte" and b2 - b3 (w1) as a "Temporary/Local Word", for when bit-addressing is required or to pass...