ToC | DocOverview | CGDoc | RelNotes | Index | PermutedIndex
| Allegro CL

| ANSI Common Lisp 12 Numbers 12.2 Dictionary of Numbers
12.2.68 dpb | Function
  Syntax: dpb newbyte bytespec integer result-integer Pronunciation: [ 'dE'pib ] or [ 'dE'pEb ] or [ 'dê'pê'bê ] Arguments and Values: newbyte - an integer. bytespec - a byte specifier. integer - an integer. result-integer - an integer. Description: dpb (deposit byte) is used to replace a field of bits within integer. dpb returns an integer that is the same as integer except in the bits specified by bytespec. Let `s` be the size specified by bytespec; then the low `s` bits of newbyte appear in the result in the byte specified by bytespec. Newbyte is interpreted as being right-justified, as if it were the result of ldb. Examples:
       (dpb 1 (byte 1 10) 0)  1024
       (dpb -2 (byte 2 10) 0)  2048
       (dpb 1 (byte 2 10) 2048)  1024
  See Also: byte, deposit-field, ldb Notes:
       (logbitp j (dpb m (byte s p) n))
       ==(if (and (>= j p) (< j (+ p s)))
              (logbitp (- j p) m)
              (logbitp j n))
  In general,
       (dpb x (byte 0 y) z)  z
for all valid values of x, y, and z. Historically, the name "dpb" comes from a DEC PDP-10 assembly language instruction meaning "deposit byte." Allegro CL Implementation Details: None.

© Franz Inc. All Rights Reserved - File last updated 2022-07-25