The byte-manipulation functions use objects called byte specifiers to designate the size and position of a specific byte within an integer. The representation of a byte specifier is implementation-dependent; it might or might not be a number. The function byte will construct a byte specifier, which various other byte-manipulation functions will accept.
The next figure shows defined names relating to manipulating bytes of numbers.
byte deposit-field ldb-test byte-position dpb mask-field byte-size ldb
Figure 12-6. Defined names relating to byte manipulation.