Appearances can be deceiving. Despite the similarities to many hand-held BASIC language programmable calculators (in particular, to Texas Instrument's own TI-74), the TI-95 is actually a sophisticated, but conventional keystroke programmable calculator. The machine has plenty of memory, expandability through its ROM/RAM cartridge port and proprietary I/O port. Somehow, though, it still feels like an odd contraption; I don't really know why, maybe it's just that a QWERTY keyboard and a keystroke programming model just feel like a mismatch to me.

My favorite programming example, the Gamma function, is not really an appropriate one for this machine; not only does its built-in factorial function calculate the extended factorial for non-integers, a true Gamma function is also available as part of the Mathematics ROM cartridge. So instead, I wrote a program for the incomplete Gamma function, which is the example presented here. To use the program, hit RUN, PGM, enter the integration limit, hit x~t, enter the argument, and hit GMA.

000  'Incomplete Gamma'
016  DFN F1:GMA@AA
023  HLT
024  LBL AA
027  STO 002
030  x~t
031  STO 001
034  y^x
035  RCL 002
038  /
039  RCL 001
042  INV
043  LN
044  /
045  RCL 002
048  =
049  STO 003
052  LBL QQ
055  STO 000
058  RCL 003
061  *
062  RCL 001
065  /
066  (
067  RCL 002
070  +
071  1
072  )
073  STO 002
076  +
077  STO 003
080  RCL 000
083  =
084  IF> 000
087  GTO QQ
090  RTN