Q.Write ALP to load 15H into R2.

Loading a constant into a register uses immediate addressing, where the data is part of the instruction and is preceded by the hash (#) sign. …

[!TLDR]

Use the immediate MOV instruction MOV R2, #15H, framed by the ORG and END directives, to load 15H into register R2.

To place a fixed number directly into a register, the 8051 uses the immediate addressing mode. In this mode the source of the data is made part of the opcode, so the value is immediately available in the instruction itself. The mnemonic for immediate data is the pound/hash sign (#), so the immediate value must be preceded by #. Writing #15H tells the assembler that 15H (hexadecimal, equal to 21 in decimal) is a constant, not an address.

A complete assembly language program also needs directives for the assembler: ORG tells the assembler where to place the code in memory (here location 0), and END marks the end of the source code.