Explain the different addressing modes in 8051.

8051 addressing modes: Immediate (operand in instruction, MOV A, #55H), Register (operand in register, MOV A, R0), Direct (operand address in instruction, MOV A, 30H), Register indirect (address in register, MOV A, @R0), and Indexed (base + offset for lookup tables, MOVC A, @A+DPTR). Each mode offers trade-offs in instruction size, execution speed, and flexibility. Immediate for constants, register for fast operations, direct for SFRs and RAM, indirect for arrays, and indexed for tables. Understanding addressing modes is essential for assembly programming and optimization.