Editing Mask (computing) (section)

===Masking bits to <code>1</code>===
To turn certain bits on, the [[Logical disjunction|bitwise <code>OR</code>]] operation can be used, following [[Logical disjunction#Bitwise operation|the principle]] that for an individual bit '''Y''',  <code>Y OR 1 = 1</code> and <code>Y OR 0 = Y</code>. Therefore, to make sure a bit is on, <code>OR</code> can be used with a <code>1</code>. To leave a bit unchanged, <code>OR</code> is used with a <code>0</code>.

Example: Masking ''on'' the higher [[nibble]] (bits 4, 5, 6, 7) while leaving the lower nibble (bits 0, 1, 2, 3) unchanged. 
     '''1001'''0101   '''1010'''0101
  OR '''1111'''0000   '''1111'''0000
   = '''1111'''0101   '''1111'''0101