Question Varbit bitmasks & shifts for significant value?

Discussion in 'Developer Support' started by Serene, Aug 2, 2016.

  1. Since Varbits are a 1 to 1 mapping to a specific value of a Varp that requires bitmasks on shifted bits, is there a way to get the bitmask & amount of shifts in a varp for specific varbits?

    This is kinda backwards since we already have the varbits class, but it would be useful for understanding how multiple values are contained in varps & the route it takes to focus on the specific bits for value extraction.

    Edit: Just realized we have a VarbitListener in the toolkit now. It kinda helps in mapping values to varbits & varbits to varps for real time value changing when logged in (as opposed to stopping & finding what varbit) but could this be used to help w/ finding the shifts/mask?
    #1 Serene, Aug 2, 2016
    Last edited: Aug 3, 2016
  2. Basically there's a least significant bit and a most significant bit, the amount of shifts is the same as the least significant bit, e.g. lsb is 5 (6th from right), so we shift 5 times, then we apply a bitmask of length msb - lsb, basically CommonMath.getBitRange(value, lsb, msb).

    Lets say we had a Varp, and that the Varp had 16 bits. The first 8 bits from the left are for ThingA, and the last 8 are for ThingB. To get the 8 bits, we need to shift and mask. For A it's easy, shift 0, mask 8 (0b11111111), for B it's also easy, shift 8, mask 8. Varbits are good in that you don't need to worry about shifting and masking most of the time.
    Serene likes this.
  3. Could you give me an example of how I could use this from the integer value returned from a Varp that carries two values?

    For example, Varp 1058 carries NMZ coffer amount and dream value. Endurance dream + 2k coins gives value of 32892. Dream varbit returns 124 and the coffer returns 2.

    Am I looking to convert that value of 32892 into a 16 bit-unsigned value, split that value into upper and lower and then shift/mask the upper & lower portions as you said to get the Varbit values of 124 and 2?
  4. Look at it in binary, it's a lot easier to spot patterns and stuff like that

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