calibration clock 12f508

[SteveB]

Joe, not all of what you see is executed by the PIC (really only a small portion). Here is a snippet of a .lst file. Only what is highlighted in RED are actual lines of code which find there way into the PIC:

  00000032            00472 _timeloopconst                  EQU     00032h
  00000064            00473 _timeloopMAX                    EQU     00064h
                      00474         INCLUDE "MAIN_4.MAC"
                      00001 
                      01236         LIST
                      00475         INCLUDE "C:\PBP\PBPPIC18.LIB"
                      00001 ;******************************************************************
                      00002 ;*  PBPPIC18.LIB                                                  *
                      00003 ;*                                                                *
                      00004 ;*  By        : Leonard Zerman, Jeff Schmoyer                     *
                      00005 ;*  Notice    : Copyright (c) 2005 microEngineering Labs, Inc.    *
                      00006 ;*              All Rights Reserved                               *
                      00007 ;*  Date      : 09/22/05                                          *
                      00008 ;*  Version   : 2.46a                                             *
                      00009 ;*  Notes     :                                                   *
                      00010 ;******************************************************************
                      00124   LIST
                      00125 ; Oscillator is 40MHz
                      01131   LIST
000000                01132     ORG RESET_ORG               ; Reset vector at 0
                      01136   LIST
000000 6A1C           01137         clrf    FLAGS           ; Clear all flags on reset
                      01141   LIST
000002 EF4A F002      01142         goto    INIT            ; Finish initialization
                      01152   LIST
000008                01153     ORG RESET_ORG + 8           ; High priority interrupt vector at 8

000008 EF69 F002      01154         goto    INTHAND         ; Goto high priority user interrupt handler
                      01166   LIST
000018                01167     ORG RESET_ORG + 18h         ; Low priority interrupt vector at 18h
000018 EF8F F002      01168         goto    INTLHAND        ; Goto low priority user interrupt handler
                      02164   LIST
00001C 50E9           02165 HSEROUTJ movf   FSR0L, W        ; Jumpman entry
                      02171   LIST
00001E                02172 HSEROUT
                      02173         CLRWDT?                 ; Keep Watchdog clear
                          M     ifndef NO_CLRWDT
00001E 0004               M         clrwdt
                          M     endif
000020 A89E           02174         btfss   PIR, TXIF       ; Wait till ready
000022 D7FD           02175         bra     HSEROUT
                      02176 
                      02177      ifdef HSERPARITY_USED
                      02178           if (HSER_BITS != 9)
                      02179         andlw   7fh             ; Clear top bit
                      02180         rcall   HSERPARITY      ; Calculate the parity
                      02181             ifdef HSER_ODD
                      02182         btfss   GOP, 0
                      02183             else
                      02184         btfsc   GOP, 0
                      02185             endif
                      02186         iorlw   80h             ; Set parity
                      02187           else
                      02188         rcall   HSERPARITY      ; Calculate the parity
                      02189         bcf     TXSTA, TX9D     ; Start parity at 0
                      02190             ifdef HSER_ODD
                      02191         btfss   GOP, 0
                      02192             else
                      02193         btfsc   GOP, 0
                      02194             endif
                      02195         bsf     TXSTA, TX9D     ; Set parity in 9th bit
                      02196           endif
                      02197       endif
                      02198 
000024 6EAD           02199         movwf   TXREG           ; Send the char
000026 80D8           02200         bsf     STATUS, C       ; Set no timeout for Serout2mod
000028 EF47 F002      02201         goto    DUNN            ; That's it

The other colors are:
BLUE = Declarations, processed by assembler
ORANGE= Assembler commands, directives, macros
GREEN = Comments
PURPLE= Labels

Also, here is a little legend for the lines of code:

 PIC   Commands        ASM             Commands			
line#  in HEX         line#             in ASM        .        
000024 6EAD           02199         movwf   TXREG           ; Send the char
000026 80D8           02200         bsf     STATUS, C       ; Set no timeout for Serout2mod
000028 EF47 F002      02201         goto    DUNN            ; That's it

EDIT: Maybe some better discriptors:
   PIC line# = ADDRESS in PIC program memory
   Commands in HEX = PIC Object Code (or OPCODE or Instruction)
   Commands in ASM = Source Code

Hope this helps you in your understanding of what goes on "under the hood"

SteveB