The tms1xxx rewrite is uploaded finally, see:
https://github.com/mamedev/mame/blob/master/src/emu/cpu/tms0980/tms0980.c

And for the TI calculator driver, see:
https://github.com/mamedev/mame/blob/master/src/mess/drivers/ticalc1x.c
(ah I see I still have to do the default button mapping)