Hmmm... I'm a little bleary eyed, but I don't think INDR works that way.
INDR is one of those magic registers that is in every bank. So it doesn't
matter what RP0,RP1 is set to, INDR is always [FSR].

To do what you want, you need to keep the FSR "pointers" in a shared address
(depends on what processor you are using, but they all have some bytes that
are in all maps). Then you would swap FSR in and out as needed. Sure, its a
bottleneck just like the W register, but that's how it works.

Regards,

Al Williams
AWC
* APP-II simplifies PIC development:
http://www.al-williams.com/awce/app1.htm


> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of David Duffy
> Sent: Monday, August 27, 2001 8:35 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: reverse indirect addressing
>
>
> At 01:44 AM 28/08/2001 +0100, you wrote:
> >Sorry, probably didn't make myself clear....
> >Specifically what I was trying to do was specify a register to be read
> >rather than reading from the INDR
> >
> >For example, if I have a block of registers set aside for some
> data, I can
> >clear sequential registers by:
> >
> >movlw MYFIRSTREG
> >movwf FSR
> >LOOP
> >movlw 0
> >movwf INDR
> >incf      FSR,1
> >goto    LOOP
> >
> >So this clears an infinite number of registers. In practice a
> quick decfsz
> >would limit it. In practice however, we often want to READ from
> one and copy
> >it into the next.
> >Clearly this could be done using
> >
> >movf READFROM1,F
> >movwf MOVETO1
> >movf READFROM2,F
> >movwf MOVETO2
> >.........
> >
> >etc, etc
> >But surely it would be better if an indirect addressing system or some
> >work-around meant you could avoid explicitly stating such commands. I ask
> >because I need to copy 96 registers from one page to another and I don't
> >want to end up writing 96*2 lines of code.......
>
> You can still use the FSR. Just keep 2 variables as pointers.
> Do the 2 banks of registers line up? (but on different banks)
> If so, you can do it in a loop, reading, changing bank, writing
> and changing bank back again each time. I haven't tested it
> but the below code should give you the idea.  :-)
>
> start:
>          movlw           .96
>          movwf           count
>          movlw           start_address
>          movwf           fsr
> loop:
>          movf            indf,w
>          bank1
>          movwf           indf
>          bank0
>          decfsz          count,f
>          goto            loop
> all_done:
>
> Regards...
>
> --
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>

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