Q.Briefly explain Arithmetic instruction.

Arithmetic instructions perform numeric operations — addition, subtraction, multiplication, division and increment/decrement — on 8-bit numbers in the 8051. …

[!TLDR]

Arithmetic instructions (ADD, ADDC, SUBB, INC, DEC, MUL AB, DIV AB, DA A) carry out numeric operations on 8-bit data; unsigned arithmetic is direct and signed arithmetic uses the OV flag.

The 8051 is an 8-bit machine (the MCS-51 family), and its arithmetic instructions perform the basic numeric operations. Unsigned arithmetic is supported directly by the instructions, while both signed and unsigned addition and subtraction can be carried out by using the OV (overflow) flag; BCD arithmetic is also possible on packed BCD data.

The main arithmetic instructions are:

• ADD / ADDC — add a register, direct byte, indirect RAM or immediate data to the accumulator (ADDC also adds the carry).
• SUBB — subtract from the accumulator with borrow; clearing CY first turns it into a plain subtraction.
• INC / DEC — increment or decrement the accumulator, a register, a direct byte or indirect RAM by one; INC DPTR increments the 16-bit data pointer.
• MUL AB — multiply the unsigned contents of A and B, giving a 16-bit product (low byte in A, high byte in B). …