130. Unpack binary coded decimal

130.1. Name

UNPK -- Unpack      binary coded decimal (68020+)

130.2. Synopsis

        UNPK        -(Ax),-(Ay),#<adjustment>
        UNPK        Dx,Dy,#<adjustment>

        No size specs

130.3. Function

Convert packed two-digit-per-byte BCD to byte-per-digit unpacked BCD.

130.4. Format

        -----------------------------------------------------------------
        |15 |14 |13 |12 |11 |10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
        |---|---|---|---|-----------|---|---|---|---|---|---|-----------|
        | 1 | 0 | 0 | 0 |   Dy/Ay   | 1 | 1 | 0 | 0 | 0 |R/M|   Dx/Ax   |
        |---------------------------------------------------------------|
        |                    16 BITS ADJUSTMENT                         |
        -----------------------------------------------------------------

        R/M = 0 -> data register.
        R/M = 1 -> Memory by pre-decrementing.
        Register Dy/Ay specifies destination register.
        Register Dx/Ax specifies source register.
        "16 BITS ADJUSTMENT" is an immediate value added to source operand.

130.5. Result

        None.

130.6. See also

PACK