lab 4

Object#4

In this experiment we perform four logical operations:

1. AND instruction to convert ASCII encoded number to BCD form.

2. OR instruction to round up data to an odd number.

3. XOR instruction to compare if two numbers are equal.

4. Complement instruction to find the 2’s complement of a number.

1. AND instruction to convert ASCII encoded number to BCD form.

An AND instruction result is 1 only if both bits of the two numbers operated on are logic 1

Procedure

-Switch to the 8080 mode by Pressing F4

-Enter the following Routine beginning at RAM location 1000h to Use the AND logic function.

CODE Mnemonics PSEUDOCODE

3E 38 MVI A,38 Load ASCII encoded number into the Register

E6 0F ANI 0Fh AND immediate data

D7 RST 2 Restart

-Press Enter after hexadecimal byte.

-Press the Esc key after D7

-Enter (D 1000) and verify that the program has been entered properly.

-Press the Esc key to return to the Command prompt.-Enable the Trace function (“g” and select Trace into)-Type “R 1000” and press enter to execute the first instruction. And result of ASCII is displayed

The ASCII value for the BCD Number 8 Is 38

< AND Instructions on GNU Simulator>Our Program with Hex Code3EC 3E 38 MVI A,38h3EE E6 0F ANI 0Fh3F0 76 hlt Snapshot of GNU Simulator

Figure AND Instruction convert ASCII to BCD Number

2. OR instruction to round up data to an odd number.

The OR logic instructions in 0.if both bits of the two binary numbers operated on are 0.

14=00001110

01=00000001

15= 00001111

Procedure


-Enter the following Routine beginning at RAM location 1100h to Use OR logic function.


3E 14 MVI A,14H Load 14 into register A

F6 01 ORI 01h Logic OR data 01 with A

D7 RST 2 Restart

-Press Enter after hexadecimal byte.-Press the Esc key after D7-Enter (D 1100) and verify that the program has been entered properly.-Press the Esc key to return to the Command prompt.-Enable the Trace function (“g” and select Trace into)-Type “R 1100” and press enter to execute the first instruction. And result of OR instruction is displayed

This program used the OR instruction and a bit mask to round up an even number to an odd number. If the number was already odd,it would stay the same.

< OR Instructions on GNU Simulator>Our Program with Hex Code

44C C3 4F 4 jmp start ;data ;code 44F 00 start: nop 450 3E 14 MVI A,14h 452 F6 01 ORI 01h 454 76 hlt

Snapshot of GNU Simulator

Figure: OR Instruction

3. XOR instruction to compare if two numbers are equal.

THE XOR instruction results is 0 if both of the two numbers operated on are alike

Procedure


-Enter the following Routine beginning at RAM location 1200h to Use XOR logic function.


3E 55 MVI A,55 Load 55 into register A

EE 01 XRI 56 XOR 56H WITH A

D7 RST 2 Restart

-Press the Esc key after D7-Enter (D 1200) and verify that the program has been entered properly.-Press the Esc key to return to the Command prompt.-Enable the Trace function (“g” and select Trace into)-Type “R 1200” and press enter to execute the first instruction. And result of XOR instruction is displayed

This program compared the two hexadecimal bytes 55h and 56h using the logic XOR instruction. If they are identical a result of zero would occur. If they were not identical ,a non-zero result would occur.

< XOR Instructions Result on GNU Simulator>

Figure XOR Instruction Result

4. Complement instruction to find the 2’s complement of a number

The Complement instruction inverts each bit of a word

Procedure


-Enter the following Routine beginning at RAM location 1300h to Use Complement logic function.

CODE MNEMONIC PSEUDOCODE

3E D5 MVI ,D5h Load D5h into A

D3 40 OUT 40 Output A to port 40

2F CMA Complement A

D3 40 OUT 40 Output A to Port 40

3C INR A Increment A by 1

D3 40 Out 40 Output A to Port 40

D7 RST 2 Restart

The immediate data D5h was loaded into the accumulator and then written to port 40.

Snapshot of GNU Simulator

lab 4

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