pic microcontroller discussion list <> wrote on Thursday, June 12, 2003
4:33 PM:

>> BTDTGTTS, but not since I started using the ^0x80 method mentioned
>> on the piclist occasionally.
>>
> Would you repeat that ?

The technique, credited to Andrew Warren (IIRC), is to add XOR 0x80 (^0x80)
to each register within a bsf STATUS,RP0 - bcf STATUS,RP0 section.  That
suppresses warnings for registers in bank 1, and causes warnings for
registers in bank 0.

e.g.
        movlw 0x12
        movwf PORTA     ; OK
        movwf TRISA     ; Produces warning 302

        bsf STATUS,RP0  ; Now in Bank 1

        movwf TRISA^0x80;       No warning
        movwf PORTA^0x80;       Warning 302, if you accidentally try to set a bank 0
register in bank 1

        bcf STATUS,RP0  ; Back to bank 0

I'm sure that Olin's famed development environment is a technically
'better' way, the above is far from perfect, but I don't usually do
significantly sized projects in assembler, so this approach works well for
me, and avoids learning yet another set of macros...

Nigel
--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk

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