The Mach3 manual (Fig. 10.1) identifies the uses of Parameters #5161 through #10306.  Can anyone advise whether any of the numbers below #5131 are in use or are they all available?  In particular, I'd like to know where Mach3 stores the current number of the loop parameter (eg. M98 P1000 L5).  Clearly the program indexes a register and acts differently when it gets to 5.  I could simplify my code if I could check the value of that register to select subroutines.