Q. Write an 8085 program and draw a flowchart to Subtract two 8-bit numbers without considering the borrow.(8085 Microprocessor Program)
Flowchart/Algorithm
Program
| Address | Mnemonics | Operand | Opcode | Comments |
| 2000 | LXI | H, 3000H | 21 | Load H-L pair with address 3000H. |
| 2001 | 00 | |||
| 2002 | 30 | |||
| 2003 | MOV | A, M | 7E | Move the 1st operand from memory to reg. A. |
| 2004 | INX | H | 23 | Increment H-L pair. |
| 2005 | MOV | B, M | 46 | Move the 2nd operand from memory to reg. B. |
| 2006 | SUB | B | 90 | Subtract B from A. |
| 2007 | INX | H | 23 | Increment H-L pair. |
| 2008 | MOV | M, A | 77 | Move the result from reg. A to memory. |
| 2009 | HLT | 76 | Halt |
Output
Before Execution:
3000H: 05H
3001H: 02H
After Execution:
3002H: 03H
Program Explanation
- This program subtracts two operands stored in memory location 3000H and 3001H, without considering the borrow taken (if any).
- Let us assume that the operands stored at memory location 3000H is 05H and 3001H is 02H.
- Initially, H-L pair is loaded with the address of first memory location.
- The first operand is moved to accumulator from memory location 3000H and H-L pair is incremented to point to next memory location.
- The second operand is moved to register B from memory location 3001H.
- The two operands are subtracted and the result is stored in the accumulator.
- H-L pair is again incremented and the result is moved from the accumulator to memory location 3002H.
