Operation: Source (Unpacked BCD) + adjustment -->;
Destination (Packed BCD)

Assembler Syntax:
PACK -(Ax), -(Ay), #<adjustment>
PACK Dx, Dy, #<adjustment>

Attributes: Unsized

Description: Adjusts and packs the low four bits of each of
two bytes into a single byte.

When both operands are data registers, the adjustment
is added to the value contained in the source register.
Bits [11:8] and [3:0] of the intermediate result are
concatenated and placed in bits [7:0] of the destination
register. The remainder of the destination register is

Condition Codes:
Not affected.