8085 Program to Count Negative Numbers | ALP to Count Negative Numbers

In the article, program of Microprocessor 8085 to count negative numbers from block of data in assembly language programming (ALP) is explained.

It is highly recommended to learn the instruction set of 8085 in detail before programming.


Find the number of negative elements (most significant bit 1) in a block of data. The length of the block is in memory location 2200H and the block itself begins in memory location 2201H. Store the number of negative elements in memory location 2300H

Flowchart for Program

8085 Program to Count Negative Numbers from the block of data


LDA 2200H

MOV C, A                  ; Initialize count

MVI B, 00                  ; Negative number = 0

LXI H, 2201H            ; Initialize pointer

BACK: MOV A, M   ; Get the number

ANI 80H                    ; Check for MSB

JZ SKIP                       ; If MSB = 1

INR B                          ; Increment negative number count

SKIP: INX H               ; Increment pointer

DCR C                         ; Decrement count

JNZ BACK                  ; If count   0 repeat


STA 2300H               ; Store the result

HLT                             ; Terminate program execution

Sample Example:

(2200H) = 04H

(2201H) = 56H

(2202H) = A9H

(2203H) = 73H

(2204H) = 82H

Result = 02 since 2202H and 2204H contain numbers with a MSB of 1.

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