`eor <reg>, <reg>, #-1` can't be encoded as an instruction. Instead use
mvn which does the same thing.
Removes a single instruction from each OF calculation for ADC and ADD.
Also no reason to use a switch statement for the source size, just use
_Bfe and calculate the offset based on operation size.
SBB caught in the crossfire to ensure it also isn't using a switch
statement.
Ryan Houdek
41ec987f3e