3. a) SMALLEST OR LARGEST NUMBER IN AN ARRAY
Aim:
To write an 8085 assembly language program that finds the smallest (or largest number in an array and execute the program using microprocessor kit.
Apparatus required: 8085 Microprocessor kit, Power supply
Algorithm:
Smallest number in an array
Step 1: Initialize HL register pair with a memory pointer.
Step 2: Get the count to B register and decrement the count.
Step 3: Increment the memory pointer
Step 4: Move contents of memory pointer to accumulator.
Step 5: Increment memory pointer and compare the contents with accumulator.
Step 6: If carry won't result move the contents of memory pointer to
Accumulator
Step7: Decrement the count
Step 8: If count becomes zero increment the memory pointer and store contents of
accumulator to that memory location.
Memory Location | Machine code | Label | Mnemonics | Comment |
4100 | 21,00,42 | LXI H, 4200 | Initialize HL register pair with a memory pointer | |
4103 | 46 | MOV B, M | Transfer the count to B register | |
4104 | 05 | DCR B | Decrement B register | |
4105 | 23 | INX H | Increment memory pointer | |
4106 | 7E | MOV A, M | Get first number to accumulator | |
4107 | 23 | LOOP2 | INX H | Increment memory pointer |
4108 | BE | CMP M | Compare the contents of memory location with accumulator | |
4109 | DA, 0D, 41 | JC LOOP1 | If [A]<[M] go to LOOP1 | |
410C | 7E | MOV A, M | Move [M] to accumulator | |
410D | 05 | LOOP1 | DCR B | Decrement the count |
410E | C2, 07, 41 | JNZ LOOP2 | If [B] is not equal to zero go to LOOP 2 | |
4111 | 23 | INX H | Increment memory pointer | |
4112 | 77 | MOV M, A | Move the smallest number to memory location | |
4113 | 76 | HLT | End execution |
Dataset 1
Data | |
Dataset 2
Data | |
Largest number in an array
Step 1: Initialize HL register pair with a memory pointer.
Step 2: Get the count to B register and decrement the count.
Step 3: Increment the memory pointer
Step 4: Move contents of memory pointer to accumulator.
Step 5: Increment memory pointer and compare contents with accumulator.
Step 6: If carry results move the contents of memory pointer to
Accumulator
Step7: Decrement the count
Step 8: If count becomes zero increment the memory pointer and store contents of
accumulator to that memory location
Memory Location | Machine code | Label | Mnemonics | Comment |
4100 | 21,00,42 | LXI H, 4200 | Initialize HL register pair with a memory pointer | |
4103 | 46 | MOV B, M | Transfer the count to B register | |
4104 | 05 | DCR B | Decrement B register | |
4105 | 23 | INX H | Increment memory pointer | |
4106 | 7E | MOV A, M | Get first number to accumulator | |
4107 | 23 | INX H | Increment memory pointer | |
4108 | BE | CMP M | Compare the contents of memory location with accumulator | |
4109 | DA, 0D, 41 | JNC LOOP1 | If [A]>[M] go to LOOP1 | |
410C | 7E | MOV A, M | Move [M] to accumulator | |
410D | 05 | LOOP1 | DCR B | Decrement the count |
410E | C2, 07, 41 | JNZ LOOP2 | If [B] is not equal to zero go to LOOP 2 | |
4111 | 23 | INX H | Increment memory pointer | |
4112 | 77 | MOV M, A | Move the smallest number to memory location | |
4113 | 76 | HLT | End execution |
Sample input and output
Memory Location | Data |
Result: Thus an 8085 assembly language program that finds the smallest (or largest number in an array was written and executed using microprocessor kit.
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b) SORTING OF NUMBERS IN AN ARRAY
AIM:
To write an 8085 assembly language program that sorts the given array in ascending order (or descending order) and execute the program using microprocessor kit.
Apparatus required: 8085 Microprocessor kit, Power supply
Algorithm
Ascending order
Step 1: Initialize HL register pair as memory pointer.
Step 2: Get the count and decrement it.
Step 3: Increment memory pointer
Step 4: Push the memory location and the count to stack pointer.
Step 5: Call subroutine.
Step 6: Get the count and memory location from stack pointer.
Step 7: Move the contents of accumulator to memory location
Step 8: Decrement the count, if it is not zero go to step 3.
Step 9: Else end the execution
subroutine:
Step 1: Move the contents of memory location to accumulator.
Step 2: Increment memory pointer and compare it with the contents of accumulator.
Step 3: If carry does not exist swap the contents of accumulator and memory pointer.
Step 4: Decrement the count, if count is not zero go to step 2.
Step 5: Else return to main program.
Memory Location | Machine code | Label | Mnemonics | Comment |
4100 | 21,00,42 | LXI H, 4200 | Initialize HL register pair with a memory pointer | |
4103 | 46 | MOV B, M | Transfer the count to B register | |
4104 | 05 | DCR B | Decrement B register | |
4105 | 23 | LOOP1 | INX H | Increment memory pointer |
4106 | E5 | PUSH H | Push the contents of HL register pair to stack pointer | |
4107 | C5 | PUSH B | Push the contents of B register to stack pointer | |
4108 | CD, 13, 41 | CALL Sub | Call subroutine to find the smallest number | |
410B | C1 | POP B | Retrieve the contents of B from stack | |
410C | E1 | POP H | Retrieve the contents of HL register pair from stack | |
410D | 77 | MOV M, A | Move the smallest number to memory location | |
410E | 05 | DCR B | Decrement register B | |
411F | C2, 05, 41 | JNZ LOOP 1 | If [B] is not equal to zero go to LOOP 1 | |
4112 | 76 | HLT | End execution |
Memory Location | Machine code | Label | Mnemonics | Comment |
4113 | 7E | MOV A, M | Transfer the contents of memory location to accumulator | |
4114 | 23 | LOOP 2 | INX H | Increment memory pointer |
4115 | BE | CMP M | Compare the contents of memory location with accumulator | |
4116 | D2, 1C, 41 | JC LOOP1 | If [A]<[M] go to LOOP1 | |
4119 | 56 | MOV D, M | Move [M] to D register | |
411A | 77 | MOV M, A | Move the contents of accumulator to memory location | |
411B | 7A | MOV A, D | Move the [D] to accumulator | |
411C | 05 | LOOP1 | DCR B | Decrement count |
411D | C2, 14, 41 | JNZ LOOP2 | If [B is not equal to zero go to LOOP 2 | |
4120 | C9 | RET | Return to main program |
Sample input and output
Memory Location | Data |
Descending order:
Step 1: Initialize HL register pair as memory pointer.
Step 2: Get the count and decrement it.
Step 3: Increment memory pointer
Step 4: Push the memory location and the count to stack pointer.
Step 5: Call subroutine.
Step 6: Get the count and memory location from stack pointer.
Step 7: Move the contents of accumulator to memory location
Step 8: Decrement the count, if it is not zero go to step 3.
Step 9: Else end the execution
Subroutine:
Step 1: Move the contents of memory location to accumulator.
Step 2: Increment memory pointer and compare it with the contents of accumulator.
Step 3: If carry exists swap the contents of accumulator and memory pointer.
Step 4: Decrement the count, if count is not zero go to step 2.
Step 5: Else return to main program
Memory Location | Machine code | Label | Mnemonics | Comment |
4100 | 21,00,42 | LXI H, 4200 | Initialize HL register pair with a memory pointer | |
4103 | 46 | MOV B, M | Transfer the count to B register | |
4104 | 05 | DCR B | Decrement B register | |
4105 | 23 | LOOP1 | INX H | Increment memory pointer |
4106 | E5 | PUSH H | Push the contents of HL register pair to stack pointer | |
4107 | C5 | PUSH B | Push the contents of B register to stack pointer | |
4108 | CD, 13, 41 | CALL Sub | Call subroutine to find the smallest number | |
410B | C1 | POP B | Retrieve the contents of B from stack | |
410C | E1 | POP H | Retrieve the contents of HL register pair from stack | |
410D | 77 | MOV M, A | Move the smallest number to memory location | |
410E | 05 | DCR B | Decrement register B | |
411F | C2, 05, 41 | JNZ LOOP 1 | If [B] is not equal to zero go to LOOP 1 | |
4112 | 76 | HLT | End execution |
Machine code | Label | Mnemonics | Comment | |
4113 | 7E | MOV A, M | Transfer the contents of memory location to accumulator | |
4114 | 23 | LOOP 2 | INX H | Increment memory pointer |
4115 | BE | CMP M | Compare the contents of memory location with accumulator | |
4116 | D2, 1C, 41 | JNC LOOP1 | If [A]>[M] go to LOOP1 | |
4119 | 56 | MOV D, M | Move [M] to D register | |
411A | 77 | MOV M, A | Move the contents of accumulator to memory location | |
411B | 7A | MOV A, D | Move the [D] to accumulator | |
411C | 05 | LOOP1 | DCR B | Decrement count |
411D | C2, 14, 41 | JNZ LOOP2 | If [B is not equal to zero go to LOOP 2 | |
4120 | C9 | RET | Return to main program |
Sample input and output
Memory Location | Data |
Result:
Thus an 8085 assembly language program that sorts the given array in ascending order (or descending order) was written and executed using microprocessor kit.
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c). BLOCK TRANSFER
Aim:
To Write an assembly language that transfer a block of data from one set of memory locations to other set of locations and test the program using 8085 microprocessor kit.
Apparatus required: 8085 Microprocessor kit, Power supply
Algorithm:
Step 1: Initialize the count value.
Step 2: Initialize the source memory pointer.
Step 3: Initialize the destination memory pointer.
Step 4: Move the contents of source memory to accumulator.
Step 5: Store the accumulator contents to destination memory location.
Step 6: Increment the source and the destination memory pointers.
Step 7: Decrement the count, if count is not zero, go to step 4.
Step 8: Else stop.
Memory Location | Machine code | Label | Mnemonics | Comment |
4100 | 06 , 05 | MVI B, 05 | Initialize a count | |
4102 | 21, 00, 42 | LXI H, 4200 | Initialize HL register pair as source memory pointer | |
4105 | 11, 00, 43 | LXI D, 4300 | Initialize DE register pair as Destination memory pointer | |
4108 | 7E | LOOP | MOV A, M | Move the contents from source location to accumulator |
4109 | 12 | STAX D | Store the contents of accumulator to destination location | |
410A | 23 | INX H | Increment memory pointer | |
410B | 13 | INX D | Increment DE register pair | |
410C | 05 | DCR B | Decrement the count | |
410D | C2, 08, 41 | JNZ LOOP | Increment memory pointer | |
4110 | 76 | HLT | End execution |
Input | Output | ||
Source location | Data | Destination location | Data |
4200 | 4300 | ||
4201 | 4301 | ||
4203 | 4302 | ||
4204 | 4303 | ||
4205 | 4304 | ||
Result:
Thus an assembly language that transfer a block of data from one set of memory locations to other set of locations was written and tested using 8085 microprocessor kit.
Questions and Answers:
1. Define: Instruction cycle, Machine cycle, T-state
2. What are 8085 interrupts? Discuss in detail.
3. With suitable examples explain in detail about the following instructions
a. STAX D
b. LDAX B
c. SPHL
d. PUSH B
4. What is stack pointer?
5. Explain the steps in execution in CALL instruction.
EXERCISE
1. A block of data is stored in the memory locations from XX55H to XX5AH. Transfer the data to locations XX80H to XX85 H in the reverse order
2. Data bytes are stored in memory locations from XX50 H to XX5FH. To insert an additional five data bytes, it is necessary to shift the data string by five memory locations. Write a program to store the data string from XX55H to XX64H.
3. Write a program to find the mode and median of a set of 10 numbers stored from location XX60.
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