I have interpreted information for 18F2450 and 18F4450 from the data sheet DS39760C. The result of compiling my changes in works, at least for me, at least no worse than the existing 18F2455 device does. I do get errors like:
/usr/local/bin/../share/sdcc/include/pic16/pic18f2450.h:162: warning 182: absolute address for sfr 'UFRM' probably out of range.
But the same error occurs for the '2455 already in the sdcc codebase.
In the attached file are the following:
updates.patch contains the edited output of svn diff for my changes to:
pic16sheet2deviceinc.tar contains a perl utility I created and used to translate an annotated description of the new devices as derived from the data sheet to devices.inc entries. I also made a description for 18F2221 according to the data sheet; the script produces the substantive equivalent of what is already in devices.inc for 18F2221. Attached are descriptions for 18F2221, 18F2450, and 18F4450.
Feel free to edit any of the above for style or egregious errors.