Thanks for bringing me up-to-date on relocatable code.
I do have the assembler/linker/librarian manual and have
looked at it but as is usually the case this is a reference
and not a tutorial and some of the discussion is only
comprehensible if one is already in the know.

> > The templates use a form for the interrupt vector,
> >
> >       ORG     0x004  is replaced by
> >
> > INT_VECTOR    CODE    0x000
>
>Should be :
>
> > INT_VECTOR    CODE    0x004
>
> > followed by the isr.  However, this bombs when I try to assemble it;
>
>Yes, since it has the same address as "RESET_VECTOR".

Sorry, a typo.  I did use INT_VECTOR     CODE    0x004 followed by
a simple ISR, just context saving, [code below] but the assembly error was:

Error - section 'INT_VECTOR' can not fit the absolute section.
Section 'INT_VECTOR' start=0x00000004, length=0x00000010

>The CODE is used anywhere where you wan't to start a new code segment.

   I hope you have the patience to tell me how that is used.  Where would
it be useful to have different CODE sections.

>You have some general confusion.  You need to ** READ THE MANUAL **.  In
>this case, that is the MPASM / MPLIB / MPLINK guide.  Understand what all
>the assembler directives do, and how they work with the linker.

Thanks for the help.  I'm not lazy and do look at the manuals first but
this is rather new to me and is not my area of training [which is physics
and astronomy] but I am interested and wish to replace chips like the
BasicX with PICs in my robotics projects.   I like the PIC simplicity,
elegance, speed, and control.

Please feel free to comment on the form of the code.  How do I treat
the portb equate, RES doesn't seem to work.   If I follow the interrupt
vector with a goto iserv and put the ISR down under Main Code, it
assembles.

    list      p=16F84
         #include <p16F84.inc>

INT_DATA                UDATA   0x0C
portb                   equ             0x06
w_temp          RES     1               ; variable used for context saving
status_temp             RES     1               ; variable used for context 
saving

;**********************************************************************
RESET_VECTOR  CODE              0x000
                         goto    start

INT_VECTOR      CODE    0x004

                 movwf   w_temp
                 movf    STATUS,w
                 movwf   status_temp

; isr code can go here or be located as a call subroutine elsewhere

                 movf    status_temp,w
                 movwf   STATUS            ;
                 swapf   w_temp,f
                 swapf   w_temp,w
                 retfie

MAIN    CODE
start           movlw   0x00
                 tris    portb
                 movlw   0x0f
                 movwf   portb

circle  goto    circle

                 END

Thanks,

John Piccirillo



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