Add instruction-part1
0 likes249 views
The document provides instructions on the 'add' operation in assembly language within the University of Duhok's Computer Science Department. It explains the format for the 'add' instruction, notes the operand types, and gives examples for adding hexadecimal values using registers. It emphasizes that two memory operands cannot be included in one instruction and describes how immediate values are sign-extended.
![• Two memory operands cannot be used in one instruction.
• When an immediate value is used as an operand, it is sign-
extended to the length of the destination operand format.
ADD AL,1355H
ADD instruction
ADD [500],[502]
By: Jawaher A. Fadhil Computer Science Dept.](https://image.slidesharecdn.com/add-instruction-part1-200521190504/85/Add-instruction-part1-3-320.jpg)
Add instruction-part1
- 1. ADD instructions Part #1 University of Duhok, Computer Science Dept.
- 2. ADD instruction The ADD instruction has the following format: ADD destination,source The ADD instruction tells the CPU to add the source and the destination operands and put the result in the destination. Destination = Destination + Source • The destination operand can be a register or a memory location. • The source operand can be an immediate, a register, or a memory location. By: Jawaher A. Fadhil Computer Science Dept.
- 3. • Two memory operands cannot be used in one instruction. • When an immediate value is used as an operand, it is sign- extended to the length of the destination operand format. ADD AL,1355H ADD instruction ADD [500],[502] By: Jawaher A. Fadhil Computer Science Dept.
- 4. Example#1 To add two numbers such as 25H and 34H, each can be moved to a register and then added together: MOV AL,25h MOV BL,34h ADD AL,BL AL= 25H +34H AL=59H BL=34H By: Jawaher A. Fadhil Computer Science Dept.
- 5. Example#2 Write the Assembly language instructions to add the values 6BH and A8H. Place the result in register AX? MOV AX,0000 MOV AL,6BH ADD AL,A8 By: Jawaher A. Fadhil Computer Science Dept. AL=AL+A8 6 B + A 8 HEX 0 1 2 . . 9 A B C D E F 10 11 12 13 14 15 16 3 1 1 1 AX= 00 13CF= 1
- 7. Example#2 Write the Assembly language instructions to add the values 6BH and A8H. Place the result in register AX? MOV AX,0000 MOV AL,6BH ADD AX,A8 By: Jawaher A. Fadhil Computer Science Dept. AX=AL+A8 6 B + A 8 3 1 1 1 AX= 01 13 CF= 0
- 8. By: Jawaher A. Fadhil Computer Science Dept.