These take a pointer to a bit field.
Bt:     Bit Test
Bts:    Bit Test and Set to one
Btr:    Bit Test and Rst to zero
Btc:    Bit Test and Compliment (toggle)
BEqu:   Set bit to value.

Bit operations are "atomic", no interrupt between the reading and writing the 
bit, important when multitasking.  For multicore use "locked" forms.

These don't take a pointer, but the actual field.
Bsf:    Bit Scan Fwd (Pos of first low one bit or -1)
Bsr:    Bit Scan Rev (Pos of first high one bit or -1)
BCnt:   Bit Cnt (Cnt of set bits)