Reference no: EM131713992

OBJECTIVES:

To code a program to add hex numbers.
To code a program to add BCD numbers.
To code a program to add two multi-byte BCD numbers.
To practice converting data from decimal to binary and hexadecimal systems.

ACTIVITY 1
Write a program to add 10 bytes of data and store the result in registers R2 and R3. The bytes are stored in the ROM space starting at 200H. The data would look as follows:

MYDATA: DB 92,34,84,129,... ;pick your own data.

Notice that you must first bring the data from ROM space into the CPU's RAM, then add them together. Use a simulator to single-step the program and examine the data.

ACTIVITY 2
Write a program to add 10 bytes of BCD data and store the result in R2 and R3. The bytes are stored in ROM space starting at 300H. The data would look as follows:

MYDATA: DB 92H,34H,84H,29H,... ;pick your own data.

Notice that you must first bring the data from ROM space into the CPU's RAM, then add them together. Use a simulator to single-step the program and examine the data.

ACTIVITY 3
Write a program to add two multi-byte BCD numbers together and store the result in RAM locations 40H - 44H. The two multi-byte items are stored in the ROM space starting at 120H and 150H. See the following example data.

ORG 120H
DATA_1: DB 54H,76H,65H,98H ;number 98657654H
DATA_2 DB 93H,56H,77H,38H ;number 38775693H

Pick your own data for your program. Notice that you must first bring the data from ROM space into the CPU's RAM and then add them together. Use a simulator to single-step the program and examine the data.

1. Explain the difference between the ADD and ADDC instructions.

2. Show how to perform the subtraction: 29H - 21H.

4. True or False. "DA A" must be used for adding BCD data only.

5. Can we use the "DA A" instruction to convert data such as 9CH into BCD without first performing an ADD instruction? Explain your answer.

6. Show a simple program to add 2345H and 56F8H.

7. Show a simple program to subtract 2345H from 56F8H.