[time command:script ?count:int=1?]

  $I0 = $count
  if $I0 > 0 goto time_something

  $R = new .TclString
  $R = '0 microseconds per iteration'
  goto time_end

time_something:
  .local float t
  t = time
time_loop:
  if $I0 == 0 goto time_done
  
  $command
  
  dec $I0
  goto time_loop
  
time_done:
  $N0 = time
  t = $N0 - t
  t *= 1000000
  
  $N0 = $count
  t /= $N0
  $I0 = t  
  $S0 = $I0
  $S0 .= ' microseconds per iteration'
  
  $R = new .TclString
  $R = $S0
time_end:
