No, this isn't a preprocessor issue. The preprocessor doesn't 'know' the
address of anything. It just manipulates text.

-- Bob Ammerman
RAm Systems

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Ruben J=F6nsson
Sent: Thursday, October 03, 2013 7:14 AM
To: Microcontroller discussion list - Public.
Subject: Re: [PIC] Load the address of a variable as 2's complement?


> Hello,
>=20
> Some time ago I wrote an Insertion sort algorithm for Mid-range PICs=20
> and today decided to optimize it as much as possible. For this I need=20
> to load the negative value of an address of a variable. Using 'movlw =20
> 0 - var' or 'addlw 0 - var', where var is a file register is not=20
> accepted by MPASM, and 'Error[151] : Operand contains unresolvable=20
> labels or is too complex' is issued.
>=20
> Currently I found 2 workarounds - one needs an extra instruction to=20
> convert the loaded address to a negative number, and the other defines=20
> an absolute address of 'var' in RAM and then a precalculated negative=20
> value of that address is used in the code.
>=20
> Both of these do not seem right, so I'm searching for a trick to=20
> negate the address of 'var' in the preprocessor, without triggering an
error.
>=20

The preprocessor doesn't know the address of var.

/Ruben


=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124
200 39 Malm=F6 Sweden
www.liros.se
Tel +46 40142078
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
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