In this program, we are going to write an assembly language program to subtract two 8-bit numbers in the 8085 microprocessor with a program flow chart and explanation of the program.
Subtract two 8-bit numbers in 8085
Program Statement
Subtract the content of memory location D001H from memory location D000H and place the result in memory location D002H.
Explanation of Program
- We have two numbers at memory locations D000H and D001H. Let these numbers be 50H and 20H. We have to subtract these numbers.
- using the SUB instruction, we will subtract the two numbers.
- Store the result at the memory location D002H.
- E.g. : D000H = 50 H and D001H = 20 H
- Result: D002H = 50H – 20H = 30H
Assembly Language Program
| Instruction | Comment | Operation |
|---|---|---|
| LXI H, D000H | set HL as memory pointer at memory location D000H | H=D0H, L=00H |
| MOV A, M | Load the first operand in the accumulator | A=50H |
| INX H | Increment HL to point to the next memory location i.e. D001H | H=D0H, L=01H D001H : 20H |
| SUB M | Increment HL to point to the next memory location i.e. D002H | A= A-M A=50-20=30H |
| INX H | Increment HL to point to next memory location i.e. D002H | H=D0H, L=02H |
| MOV M, A | Store the result | D002H= 30H result |
| HLT | terminate program execution | Stop |
Flow Chart of Program
