AlmostTI is a program that emulates Z80-based graphing calculators made by
Texas Instruments.  Currently, it supports TI-82, TI-83, TI-83+, TI-83+SE,
TI-84+, TI-84+SE, TI-85, and TI-86.

It requires ROM image to operate, which must be obtained separately.  RAM
state is preserved across different runs, making complex usage scenarios
possible.