Function:

Clears the specified bit in the register/memory operand. The bit number (CL
or immediate) is ANDed with 07 (for 8-bit operands) or 0F (for 16-bit
operands) to get a valid bit number. No flags are affected by this
operation, except by CLEAR1 CY and CLEAR1 DIR.

The first (smaller) clock count of each pair is for register operands.
Note that 0F is treated as <POP CS> on the 88/86 and prefixes newer
instructions on 286+ CPUs.

(Supplied by Anthony Naggs)