Q.What is the function of Register R?

The R registers (R0-R7) are general-purpose working registers of the 8051 used to store data and intermediate results temporarily during a program. Four banks of these registers are available. …

[!TLDR]

Registers R0-R7 are general-purpose working registers that temporarily store data during program execution.

The 8051 provides eight general-purpose registers named R0 to R7. They are used to hold operands, counters, addresses (R0/R1 serve as pointers in register-indirect addressing) and intermediate results while a program runs, reducing the number of slower memory accesses. These eight registers exist in four banks (Bank 0 to Bank 3) in the lower RAM; the active bank is selected by bits in the PSW, allowing fas …