Here's a patch to add support for the PIC16F684. Two
main changes were required:
p16f684.inc (from GPUTILS / Microchip)
The change to device.c just tells SDCC what the spec of
the 16F684 microcontroller is, and the change to
p16f684.inc is to allow the perl script (can't remember
what it's called) to successfully generate a correct
version of pic16f684.h (also attached, for convenience)
for inclusion in the C progs.
I've submitted changes to the maintainer of "picp"
(Linux command line interface to the Microchip
"Picstart Plus" programmer) in order to ensure that the
the resultant hex file from SDCC/GPUTILS can be burned
to the PIC. These changes are attached here too for
convenience and completeness, but are not required for
the SDCC change (obviously!).