PIC (Microchip) assembler syntax query

Hi, Maybe deserves an RTFM response, but I've just spent an hour on this
with no success. I appear to be trying what the various advice notes
suggest, but it isn't working.

I'm declaring data memory space (starts at 0x20), up to now have been doing
it clunkily as follows:

REG1 EQU 0x20
REG2 EQU 0x21

But with other platforms one usually declares the locations themselves, as
in:

ORG 0x20
REG1 DB 0
REG2 DB 0


Attempting this with Microchip for 12C or 16F series results in a error
message "Overwriting previous address contents (0020)".
Would appreciate it if someone could tell me the correct syntax, and what
that error message means. TIA


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