[AnotherGoodName]

Think of a way you can make the number of each case 0 or 1 then you have a single sum of all possibilities where that 0 or 1 multiplies the portion of the switch statement it represents (the 0 will mean not active the 1 includes it).

Eg. If we had just 1 or 2 as options for the case statements note that test1 = xor(var1 & 0x1, var1>>1 & 0x1) & var1 will, with integer rounding, equal ‘1’ if var1 is one or ‘0’ if var1 is 2,3 or 4. (If it goes to 5 you need another xor at the next highest bit).

Likewise test2 = xor(var1 & 0x1, var1>>1 & 0x1) & var1<<1 equals ‘0’ if var1 is 1, 3 or 4 but it equals ‘1’ if it’s two.

So (test1 * (value on var1 being 1) + (test2 * (value on var1 being 2)) will get you a branchless version for the simple either 1 or 2 case. This will pretty much always be much slower than the branching version but some types of systems out there don’t really do branching and are linear. This type of zeroing trick is really common on matrix multipliers.

Essentially your creating binary logic gates that give 0 or 1 for the exact value you want and blindly multiplying that by the value it would have produced if 1.