The HP-33E/C that could have been.

[Kostas Kritsilas]

Going strictly from memory of those days, I believe that the contemporary calculator for the HP-25/25C was the TI-58/58C. and the TI-58/58C had 480 partially merged program steps, maximum (I seem to recall that you could re-allocate program steps to registers). The HP-67 (224 fully merged steps) equivalent was the TI-59 (960 partially merged steps). The later HP-29C had 98 or 100 fully merged steps, and a bunch of added programming features over the HP-25/25C like indirect addressing and subroutines, some of which were in the TI-58/58C already.

The earlier generation programmables were the HP-55 (49 un-merged steps) and HP-65 (100 un-merged(?) steps) vs. the SR-56 (100 un-merged steps) and SR-52 (I don't remember how many steps it had). I also don't recall the register counts for each.