Factorial of a number in micro controller 8051?

Answer 1

LXI SP, 27FFH ; Initialize stack pointer

LDA 2200H ; Get the number

CPI 02H ; Check if number is greater than 1

JC LAST

MVI D, 00H ; Load number as a result

MOV E, A

DCR A

MOV C,A ; Load counter one less than number

CALL FACTO ; Call subroutine FACTO

XCHG ; Get the result in HL

SHLD 2201H ; Store result in the memory

JMP END

LAST: LXI H, 000lH ; Store result = 01

END: SHLD 2201H

HLT

Subroutine Program:

FACTO:LXI H, 0000H

MOV B, C ; Load counter

BACK: DAD D

DCR B

JNZ BACK ; Multiply by successive addition

XCHG ; Store result in DE

DCR C ; Decrement counter

CNZ FACTO ; Call subroutine FACTO

RET ; Return to main program