@ECHO OFF
SET TIMEON=%TIME:~0,-3%
:TIME1
SET /A S9=%TIME:~7,1%,S1+=S
SET /A H=S1/3600,M=S1%%3600/60,S=S1%%3600%%60
CLS&ECHO stopwatch %H%:%M%:%S% current:%TIME:~0,-3% timeon:%TIMEON% secs=%S1% %S9%
::SET /A S1/(S1-100000) 2>nul||GOTO NEXT
:TIME0
SET /A S=(((%TIME:~7,1%-S9)*2+1)%%2*(%TIME:~7,1%-S9)*10)/(((%TIME:~7,1%-S9)*2+1)%%2*(%TIME:~7,1%-S9)*10-1)
GOTO TIME%S%