Commodore PET User Manual page 80

Table 3-3. Boolean Truth Table
The AND operation results in a 1 only if both bits are 1.
1 AND 1
=
1
o
AND 1
=
0
1 AND 0
=
0
o
AND
0
=
0
The OR operation results in a 1 if either bit is 1.
1 OR 1
=
1
o
OR 1
=
1
1 OR 0
=
1
o
OR 0 = 0
The NOT operation logically complements each bit
NOT 1
=
0
NOT 0
=
1
Bit-Oriented Boolean Operations
We include below a discussion of binary digit (bit) oriented Boolean opera-
tions. This discussion is presented for those who are interested in the details
of how these operations are performed. If vou do not understand iL skip iL You
are not skipping anything vou must know.
Bitwise Boolean operations are normally performed on unsigned, positive
16-bit numbers; these numbers range from 0 to FFFF hexadecimal. 0 to 188888
octal. or
0
or 65535 decimal. However, the numbers must be input to the PET in
the range ±32767 decimal. Appendix F contains hexadecimal-PET decimal con-
version tables. If Vou are already familiar with Boolean operations, vou have prob-
ablv used binary, octal. or hexadecimal notation, because the bit-by-bit conver-
sion is straightforward. PET BASIC accepts onlv decimal numbers. even for these
Boolean operations. Here are some examples of bitwise Boolean operations:
Operation
1 AND 1
1 AND -1
15 OR 240
NOT 0
NOT 1
results in 1
resu Its in 1
resu Its in 255
results in -1
results in -2
Hexadecimal equivalent
1 AND 1 equals 1
1 AND FFFF equals 1
F OR FO equals FF
NOT 0 equals FFFF
NOT 1 equals FFFE
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