|Function:||Move Data To/From External Memory (XRAM)|
Description: MOVX moves a byte to or from External Memory into or from the Accumulator.
If operand1 is @DPTR, the Accumulator is moved to the 16-bit External Memory address indicated
by DPTR. This instruction uses both P0 (port 0) and P2 (port 2) to output the 16-bit address and
data. If operand2 is DPTR then the byte is moved from External Memory into the Accumulator.
If operand1 is @R0 or @R1, the Accumulator is moved to the 8-bit External Memory address indicated
by the specified Register. This instruction uses only P0 (port 0) to output the 8-bit address and data.
P2 (port 2) is not affected. If operand2 is @R0 or @R1 then the byte is moved from External
Memory into the Accumulator.