PIC Example programs

I am giving you some of the PIC programs which will help you understand the PIC programming better...Execute these using MPLAB and see the results

; Program to add two numbers
; By Binoy B. Nair, Lecturer EIE

#include p16f877a.inc
num equ 0X50
org 00h

a movlw 0x04
movwf num
movlw 0x01
addwf num
goto a
end

; Program to subtract two numbers
; By Binoy B. Nair, Lecturer EIE

#include p16f877a.inc
num equ 0X50
org 00h

a movlw 0x04
movwf num
movlw 0x01
subwf num,0
goto a
end

; Program to multiply two numbers num1=4, num2=3
; product is stored in num1
; By Binoy B. Nair, Lecturer EIE

#include p16f877a.inc
num1 equ 0X50
num2 equ 0x53
org 00h
start
movlw 0x03 ; loading 4-1=3 into num1
movwf num1
movlw 0x03
movwf num2
a addwf num2
decfsz num1,1
goto a
goto start
end

the next one is a little different


; Program to read from a port and write to a Port

list p=16F877A ; Selects the microcontroller

W equ 0x00 ; Variable to hold a constant '0'
F equ 0x01 ; Variable to hold a constant '1'
STATUS equ 0x03 ; Address of STATUS register
RP0 equ 0x05 ; Position of RP0 bit in STATUS register
ADCON1 equ 0x9F ; Address of ADCON1 register
PORTA equ 0x05 ; Address of PORTA register
TRISA equ 0x05 ; Address of TRISA register
PORTD equ 0x08 ; Address of PORTD register
TRISD equ 0x08 ; Address of TRISD register

org 0x0000

Main:
bsf STATUS, RP0 ; Select bank 1

movlw 0x06 ; WREG = 0x06
movwf ADCON1 ; ADCON1 = WREG, Configure PortA as
; digital I/O

movlw 0x00 ; WREG = 0x00
movwf TRISA ; TRISA = WREG, Port A is output

movlw 0xFF ; WREG = 0xFF
movwf TRISD ; TRISA = WREG, Port D is input

bcf STATUS, RP0 ; Select bank 0

main_loop:
movf PORTD, W ; WREG = PORTD, read Port D to WREG
movwf PORTA ; PORTA = WREG, Output WREG to Port A

goto main_loop ; Goto main_loop

end ; Physical end of program