i want eval if integer number between 0 , 255 equal 0 or equal 224.
i have code:
if (!num || 224 == num) is there way using bitwise operation?
i tried , have valid: 0, 31, 32, 63 ,64, 95, 96, 127, 128, 159, 160, 191, 192, 223, 224, 255. obvious bad because need 0 , 224.
!((num+1) & 30)
yes, , range of input makes easier.
you can use (x - 1) >> 31 detect whether x 0 (technically not portable, work)
it relies on x never being smaller 0, and, non-portably, on right shift on signed int being arithmetic shift (which case).
similarly, can use ((x ^ 224) - 1) >> 31 detect 224.
just put them this:
int mask = ((x - 1) >> 31) | (((x ^ 224) - 1) >> 31); and there go.
