ASSIGNMENTS on INTRODUCTION TO Z80 INSTRUCTIONS AND PROGRAMMING TECHNIQUES( part 1)

ASSIGNMENTS on INTRODUCTION TO Z80 INSTRUCTIONS AND PROGRAMMING TECHNIQUES

Note: In the following assignments, substitute high-order memory address XX with the high-order address and PORT with the output port address of your single-board microcomputer system, Use your own data if data are not given, and specify memory addresses for labels such as INBUF and OUTBUF.

Section

l. Write mnemonics to load 39_H into register B and 92_H into register D. Save the contents of B in register L, and display the contents of D at PORT 1.

2. Write instructions to load 47_H into register Band F2_H into register C using one instruction. Store the contents of C in memory location XX80_H and dis­play the contents of B at PORTl. Assemble the Hex code and store the code in memory.

3. Write instructions to load A2_H into register D and XX80_H into register HL.Copy the contents of D into memory location XX80_H.

4. Write instructions to load A7_H into register D and XX55_H into register BC.Copy the contents of D using BC as a memory pointer.

5. Write instructions to load 98_H in memory location XX40_H and F9H in loca­tion XX70_H. Exchange the contents of these memory locations. Assemble and execute the code.

6. Specify the register contents and the flag statuses after execution of the fol­lowing instructions. Show only the changes in register contents, and when flags are not affected, write NA.

7. Write instructions to read the input port 80_H and output the reading to the port 05_H (see Figure 8.11). What appliances will be turned on with this output?

8. Write comments to explain the functions of the following instructions:

LD HL, 2065H

LD (HL), 00H

HALT

9. What are the contents of the accumulator after the execution of the instruc­tion SUB A? Specify the status of the Z and CY flags.

10. Write the instructions to load FF_H into the accumulator and increment A.

Specify the status of the S, Z, and CY flags after the execution of the incre­ment instruction.

11. In the previous assignment (#10), replace the increment instruction with the instruction ADD A, 01H and explain how the flags S, Z, and CY are af­fected after the addition.

12. Specify the register contents and the flag status after the execution: of the following instructions. What is being displayed at OUTPRT?

13. Write instructions to load 40FF_H into register HL and increment HL. Spec­ify the contents of register HL.

14. Register HL contains 20FF_H. What are the contents of register HL if the byte 01_H is added (not incremented) to register L? What are the statuses of the S, Z, and CY flags after the addition?

15. Write instructions to perform the operations listed in 14, and assemble the code showing memory addresses.

16. Show the contents of the registers and the memory locations that are af­fected after the execution of the following instructions. Explain the differ­ence between the two INC instructions shown below.

LDHL,209FH

LD(HL), FFH

INC (HL) INCHL

HALT

17. Find the results of the following operations and explain the difference be­tween the two results.

18. Load 48A2_H into register BC. Subtract the contents of C from B. If the an­swer is in 2’s complement, display 01_H at PORT; otherwise, display the re­sult. Assemble the code and execute the program.

19. Execute the program in 18 by loading F247_H in register BC.

20. Three data bytes are stored in memory locations XX50, XX5l, and XX52_H. Write instructions to subtract the bytes stored in memory locations XX50 and XX5l from the byte stored in location XX52_H. If the answer is in 2’s complement, display FF_H at PORT; otherwise, display the answer. Execute the instructions with the following set of data in Hex.

Set 1: XX50 = 32, XX51 = 78, XX52 = F9

Set 2: XX50 = 67, XX51 = 98, XX52 = F9

21. The Relative Jump instruction JR NZ, 68H is stored in memory locations XXA7_H and XXA8_H. Calculate the jump location.

22. If the opcode of the Relative Jump instruction JR NC, 8FH is located at memory location XX50H, calculate the jump location.

23. Assemble the code in Illustrative Program 1 (Section 8.6.3) and replace the instruction JP NZ, NEXT with the appropriate Relative Jump instruction and offset.

24. In Illustrative Program 2 (Figure 8. 10), assemble the code and replace the Jump instructions JP NC, SKIPCY; and JP NZ, NXTBYT with the appro­priate Relative Jump instructions and their offsets.