Editing Mask (computing) (section)

===Masking bits to <code>0</code>===
More often in practice, bits are "masked ''off''" (or masked to <code>0</code>) than "masked ''on''" (or masked to <code>1</code>). When a bit is <code>AND</code>ed with a 0, the result is always 0, i.e. <code>Y AND 0 = 0</code>. To leave the other bits as they were originally, they can be <code>AND</code>ed with <code>1</code> as <code>Y AND 1 = Y</code> 

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