' --- GLOBAL VARIABLES (Must retain their values between counter readings) ---
' Declare these at the top of your program or in a GLOBAL block.
DIM LastRaw32BitReading AS INTEGER      ' Stores the previous 32-bit counter reading (0 to 4,294,967,295)
DIM TotalSigned64BitCount AS INTEGER    ' The accumulated 64-bit signed counter value
DIM CurrentRaw32BitReading AS INTEGER
DIM SignedDelta AS INTEGER

' --- INITIALIZATION (Run ONCE at program startup) ---
' Read the very first value of the counter to set the baseline.
' This assumes the counter starts at 0 or a known, consistent value.
' If the counter's initial state is truly arbitrary, you might need a reset mechanism.
TotalSigned64BitCount = 0 ' Start the total count at zero
LastRaw32BitReading = EXT_READ_32BIT_COUNTER_FUNCTION() ' REPLACE with your actual function to read the 32-bit counter

' --- COUNTER READING AND UPDATE LOGIC (Place this inside your main loop or timer interrupt) ---
' This block should be executed every time you want to update the counter.

   
   ' 1. Read the current 32-bit unsigned value from your external counter.
   CurrentRaw32BitReading = EXT_READ_32BIT_COUNTER_FUNCTION() ' REPLACE with your actual function

   ' 2. Calculate the raw difference.
   '    MicroMite BASIC performs this subtraction using 64-bit signed arithmetic.
   '    If the 32-bit counter has rolled over or under, this 'SignedDelta' will
   '    be a large positive or negative 64-bit number.
   SignedDelta = CurrentRaw32BitReading - LastRaw32BitReading

   ' 3. Correct for 32-bit unsigned rollovers/roll-unders.
   '    This is the core "magic" that converts the raw 64-bit difference
   '    into the correct signed 32-bit delta, accounting for the 32-bit wrap.
   '    Constants:
   '    &H100000000 = 2^32 = 4,294,967,296 (the full range of a 32-bit unsigned int)
   '    &H80000000  = 2^31 = 2,147,483,648 (the value of the 32-bit sign bit)

   ' If SignedDelta is a large positive number (e.g., Last=10, Current=4294967290, delta=4294967280)
   ' This indicates a roll-under from a small value to a large value (e.g., 10 -> -6)
   IF SignedDelta > 2147483647 THEN ' If delta > (2^31 - 1)
       SignedDelta = SignedDelta - 4294967296 ' Subtract 2^32 to make it correctly negative
   ' If SignedDelta is a large negative number (e.g., Last=4294967290, Current=10, delta=-4294967280)
   ' This indicates a roll-over from a large value to a small value (e.g., -6 -> 10)
   ELSEIF SignedDelta < -2147483648 THEN ' If delta < -2^31
       SignedDelta = SignedDelta + 4294967296 ' Add 2^32 to make it correctly positive
   END IF

   ' 4. Add the corrected signed delta to the total 64-bit counter.
   TotalSigned64BitCount = TotalSigned64BitCount + SignedDelta

   ' 5. Update LastRaw32BitReading for the next iteration.
   LastRaw32BitReading = CurrentRaw32BitReading

' --- TotalSigned64BitCount now holds the accurately extended signed 64-bit counter value ---
' PRINT "Extended 64-bit Counter: "; TotalSigned64BitCount

x%=(x%<<32)/2^32

const z%=2^32

x%=(x%<<32)/z%