Hiya, Steve

My little page bit macro seems to work, so far.  I did add lines to suppress
the warnings generated by the macro: the remaining warnings simply tell me
if I have missed any places where the macro is needed.  Note that it doesn't
use any forward references: it simply flips (inverts) the page bit from the
current page.  It will work just fine until I start using the new 8K parts
... <sigh>.

I also wrote a quick "goto" macro - it does the same thing except that it
doesn't need to change the page bit back after going to the new address.

How I use the macros is simple: if I know that a particular subroutine or
jump is on the other page, I simply use xgoto or xcall (Andy Warren's idea
for the macro names).  If I miss any places that need the macros, the
assembler gives warning messages telling me where.

I guess my next trick will be to add error checking to make sure that the
page bits are really correct.  I'll simply output an error message if there
is a problem.  That should cover situations where I might accidently use an
xcall instead of a call.

xcall           MACRO   routine         ;flip ROM page bit
    if          ($ & 0x800)
      bcf       PCLATH,3
    else
      bsf       PCLATH,3
    endif
    errorlevel  -306
    call        routine
    errorlevel  +306
    if          ($ & 0x800)
      bsf       PCLATH,3
    else
      bcf       PCLATH,3
    endif
    endm


xgoto           MACRO   routine         ;flip ROM page bit
    if          ($ & 0x800)
      bcf       PCLATH,3
    else
      bsf       PCLATH,3
    endif
    errorlevel  -306
    goto        routine
    errorlevel  +306
    endm

Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, Alberta, CANADA
(403) 489-3199 voice     (403) 487-6397 fax