Q. Write an 8085 program and draw a flowchart to add two 16-bit numbers without considering the carry.(8085 Microprocessor Program)
Flowchart/Algorithm
Program
| Address | Mnemonics | Operand | Opcode | Comments |
| 2000 | LHLD | 3000H | 2A | Load H-L pair with 1st operand from 3000H. |
| 2001 | 00 | Lower-order of 3000H. | ||
| 2002 | 30 | Higher-order of 3000H. | ||
| 2003 | XCHG | EB | Exchange H-L pair with D-E pair. | |
| 2004 | LHLD | 3002H | 2A | Load H-L pair with 2nd operand from 3002H. |
| 2005 | 02 | Lower-order of 3002H. | ||
| 2006 | 30 | Higher-order of 3002H. | ||
| 2007 | DAD | D | 19 | Add D-E pair with H-L pair. |
| 2008 | SHLD | 3004H | 22 | Store the result at address 3004H. |
| 2009 | 04 | Lower-order of 3004H. | ||
| 200A | 30 | Higher-order of 3004H. | ||
| 200B | HLT | 76 | Halt. |
Output
Before Execution:
3000H: 02H
3001H: 04H
3002H: 04H
3003H: 03H
After Execution:
3004H: 06H
3005H: 07H
Program Explanation
- This program adds two 16-bit operands stored in memory locations 3000H-3001H and 3002H-3003H, without considering the carry produced (if any).
- Let us assume that the operands stored at memory locations 3000H-3001H is 02H-04H and 3002H-3003H is 04H-03H.
- The H-L pair is loaded with the first 16-bit operand 0204H from memory locations 3000H- 3001H.
- Then, the first 16-bit operand is moved to D-E pair.
- The second 16-bit operand 0403H is loaded to H-L pair from memory locations 3002H- 3003H.
- The two operands are added and the result is stored in H-L pair.
- The result is stored from H-L pair to memory locations 3004H-3005H.
