Program to Sort the array in Descending Order

Q. Write an 8085 program and draw a flowchart to Sort the array in Descending Order.(8085 Microprocessor Program)

Flowchart/Algorithm

Program

Address	Mnemonics	Operand	Opcode	Comments
2000	MVI	B, 05H	06	Initialize counter-1.
2001			05
2002	MVI	C, 05H	0E	Initialize counter-2.
2003			05
2004	LXI	H, 3000H	21	Load H-L pair with address 3000H.
2005			00
2006			30
2007	MOV	A, M	7E	Move the number from memory to reg. A.
2008	INX	H	23	Increment H-L pair.
2009	CMP	M	BD	Compare the number with next number.
200A	JNC	2015H	D2	Don’t interchange if number > next number.
200B			15
200C			20
200D	JZ	2015H	CA	Don’t interchange if number = next number.
200E			15
200F			20
2010	MOV	D, M	56	Otherwise, swap the numbers. Move next number from memory to D.
2011	MOV	M, A	77	Move the first number from A to memory.
2012	DCX	H	2B	Decrement H-L pair.
2013	MOV	M, D	72	Move next number from D to memory.
2014	INX	H	23	Increment H-L pair.
2015	DCR	C	0D	Decrement counter 2.
2016	JNZ	2007H	C2	If counter-2 ≠ 0, repeat.
2017			07
2018			20
2019	DCR	B	05	Decrement counter-1.
201A	JNZ	2002	C2	If counter-1 ≠ 0, repeat.
201B			02
201C			20
201D	HLT		76	Halt

Output

Before Execution:

3000H: 05H
3001H: 15H
3002H: 01H
3003H: 65H
3004H: 32H

After Execution:

3000H: 65H
3001H: 32H
3002H: 15H
3003H: 05H
3004H: 01H

Program Explanation

This program sorts an array in descending order.
Let us assume that there are five numbers in the array and its starting address is 3000H.
Initially, counter-1 and counter-2 are initialized with the size of the array.
H-L pair is pointed to the starting address of the array.
In the first iteration, the first number is compared with the second number.
If first number > second number, then do not interchange them. Otherwise, if the first number < second number, then swap them.
In the next iteration, the first number is compared with the third number.
If first number > third number, then do not interchange them. Otherwise, if the first number < third number, then swap them.
In the next iteration, the first number is compared with the fourth number and the process continues until counter-2 becomes zero.
When counter-2 becomes zero, counter-1 is decremented and the process continues until all the numbers are arranged in descending order.