I figured this might be useful to other people, so I’m posting the routines needed to get RandomReal[] and related functions to emulate the rand() function (and ilk) on TI calculators:

This is based on the PRNG method plug-in framework in Mathematica that is described here. For instance, here is the Mathematica equivalent of executing 0→rand:rand(10) (for Zilog Z80 calculators like the TI-83 Plus) or RandSeed 0:rand() (for Motorola 68k calculators like the TI-89):

Due to differences in precision, there is bound to be some discrepancy in the least significant figures of the results from the calculators and the results from the Mathematica emulation; still, I believe that this is a serviceable fake.

What computer language is this coded in?

It’s in

Mathematica, as noted in the post. :)