AND - mkilgore/QB64pe GitHub Wiki

The logical AND numerical operator compares two values in respect of their bits. If both bits at a certain position in both values are set, then that bit position is set in the result.

result = firstvalue AND secondvalue

• AND compares the bits of the firstvalue against the bits of the secondvalue, the result is stored in the result variable.
• If both bits are on (1) then the result is on (1).
• All other conditions return 0 (bit is off).
• AND is often used to see if a bit is on by comparing a value to an exponent of 2.
• Can turn off a bit by subtracting the bit on value from 255 and using that value to AND a byte value.

Example 1:

         101
         AND
         011
        -----
         001

The 101 bit pattern equals 5 and the 011 bit pattern equals 3, it returns the bit pattern 001 which equals 1. Only the Least Significant Bits (LSB) match. So decimal values 5 AND 3 = 1.

      11111011
        AND
      11101111
     ----------
      11101011

Both bits have to be set for the resulting bit to be set. You can use the AND operator to get one byte of a two byte integer this way:

firstbyte = twobyteint AND 255

Since 255 is 11111111 in binary, it will represent the first byte completely when compared with AND.

To find the second (HI) byte's decimal value of two byte INTEGERs use: secondbyte = twobyteint \ 256

 DO
  INPUT "Enter Integer value from -32768 to 32767 (Enter quits): ", INTvalue& 
  IF INTvalue& < -32768 OR INTvalue& > 32767 OR INTval& = 0 THEN EXIT DO
  FOR...NEXT exponent = 15 TO 0 STEP -1
    IF...THEN (INTvalue& AND 2 ^ exponent) THEN PRINT "1"; ELSE PRINT "0";
  NEXT
  PRINT " "
 LOOP UNTIL INTvalue& = 0 'zero entry quits

Example output for 6055.

0001011110100111

Note: The value of 32767 sets 15 bits. -1 sets all 16 bits. Negative values will all have the highest bit set. Use LONG variables for input values to prevent overflow errors.

• OR, XOR, NOT (logical operators)
• AND (boolean)
• Binary, Boolean