I will add the special case of TI-99/4A TI-basic which is probably one of the worst offender in the category of slow interpreters.

• TI-Basic (and also TI-Extended Basic) are especially slow because the interpreter was not written in TMS-9900 machine language as one would suppose, but was written in GPL (Graphic Programming Language) which was a kind pseudo-code (a bit like Java bytecode or UCSD P-Code or Apple II's Sweet16) to add a level of abstraction to the system.

• On the base console, the Basic program was not stored in CPU addressable RAM but in the Video-RAM of the display processor. Each byte read or written required I/O commands.

• As all other interpreters, everything is done in floating point. The peculiarity of the TI machine is that the floating point routines implemented were at the same level of sophistication as their FP routines in the TI calculators, i.e. 8 byte for storage, 13 digits precision with -99 to +99 range for the exponent (decimal storage). This had the advantage of nice calculation capacity without the precision issue with the binary floating points of other machines but cost quite some performance.

I will add the special case of TI-99/4A TI-basic which is probably one of the worst offender in the category of slow interpreters.

• TI-Basic (and also TI-Extended Basic) are especially slow because the interpreter was not written in TMS-9900 machine language as one would suppose, but was written in GPL (Graphic Programming Language) which was a kind pseudo-code (a bit like Java bytecode or UCSD P-Code or Apple II's Sweet16) to add a level of abstraction to the system.

• On the base console, the Basic program was not stored in CPU addressable RAM but in the Video-RAM of the display processor. Each byte read or written required I/O commands.

• As all other interpreters, everything is done in floating point. The peculiarity of the TI machine is that the floating point routines implemented were at the same level of sophistication as their FP routines in the TI calculators, i.e. 8 byte for storage, 13 digits precision with -99 to +99 range for the exponent (decimal storage). This had the advantage of nice calculation capacity without the precision issue with the binary floating points of other machines but cost quite some performance.

• Syntax and semantic check at start. When invoking RUN command the interpreter analyses the whole program to see if there are still some errors in the code. For big programs this can take a lot of time (minute).

All the other issues listed for the other interpreters apply also here: linear search for line numbers and for variables. Garbage generating string functions with stop the world garbage collection from time to time.