> From: Ray Gardiner <ray@NETSPACE.NET.AU>
>
> [cut]
> 3. I have found that it pays to ALWAYS inspect the *.LST output
>    from the assembler to check for page crossing on tables etc.
> [cut]

One can automate this inspection by using the 'error' directive e.g.
my favourite technique goes like this:


PAGESIZE equ    100h            ; Page size for the processor
PAGEMASK equ    10000h-PAGESIZE ; Mask for address bits which indicate page

; Define a few macros...
table   macro   reg
        movlw   high ($+4)
        movwf   pclath
        movf    reg,w
        addwf   pcl,f
first   =       $
        endm

endtab  macro
        if      (($-1) & PAGEMASK) != (first & PAGEMASK)
        error   'Table page boundary overflow'
        endif

; Now use the macros in open code...
        movlw   1
        movwf   jumpindex
        call    foobar
        ...
foobar  table   jumpindex       ; jumpindex reg contains a value 0, 1, 2 etc.
        dt      4,2,77,4,5      ; The table entries (as retlw's etc)
        endtab



The endtab macro ensures that the actual table does not cross a page
boundary.  If it does, your assembly fails and you can manually resolve
the problem by shifting the table to another location.

As shown, the above works for the 16CXX devices with which I am very familiar.
The 16C5X parts may require additional restrictions which should be codified
in the macros.

Regards,
SJH
Canberra, Australia