These take a pointer to a bit field.
Bt:     Bit Test
Bts:    Bit Test and Set to one
Btr:    Bit Test and Reset to zero
Btc:    Bit Test and Compliment (toggle)
BEqual: 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 Forward (Pos of first low one bit or -1)
Bsr:        Bit Scan Reverse (Pos of first high one bit or -1)
PopCount:   Population Count (Count of set bits)