Q.Briefly explain Data transfer instruction.

Data transfer instructions copy data from one place (register, memory or an SFR) to another inside the 8051 without changing the source. …

[!TLDR]

Data transfer instructions (MOV, MOVX, MOVC, PUSH, POP, XCH) move or copy data within the 8051 without affecting the source or, generally, the flags.

Data transfer instructions are used to move data from a source location to a destination location inside the 8051. The instruction format is a mnemonic followed by the destination and source operands. A key feature is that a data MOV copies the data to the destination but does not alter the contents at the source, and in general these instructions have no effect on the PSW flags (the exception being a MOV or POP directly to the PSW).

The main data transfer instructions are:

• MOV — moves/copies a byte within the internal 8051 memory (register, direct RAM, SFR).
• MOVX — moves a byte to/from external RAM.
• MOVC — moves a code byte (from program memory / look-up table) into the accumulator.
• PUSH / POP — copy a direct byte onto or off the stack; PUSH increments the stack pointer (SP) then stores, POP reads then decrements SP. …