Function: gettime
Section: programming/specific
C-Name: gettime
Prototype: l
Help: gettime(): time (in milliseconds) since last call to gettime.
Doc: returns the time (in milliseconds) elapsed since either the last call to
 \kbd{gettime}, or to the beginning of the containing GP instruction (if
 inside \kbd{gp}), whichever came last.

 For a reentrant version, see \tet{getabstime}.