Changeset 3723 for trunk/j/src/org/armedbear/lisp/ldb.lisp

Timestamp:

09/12/03 14:18:10 (19 years ago)

Author:

piso

Message:

DPB

File:

• trunk/j/src/org/armedbear/lisp/ldb.lisp (modified) (2 diffs)

trunk/j/src/org/armedbear/lisp/ldb.lisp

@@ -2 +2 @@
 ;;;
 ;;; Copyright (C) 2003 Peter Graves
-;;; $Id: ldb.lisp,v 1.1 2003-09-11 01:16:00 piso Exp $
+;;; $Id: ldb.lisp,v 1.2 2003-09-12 14:16:44 piso Exp $
 ;;;
 ;;; This program is free software; you can redistribute it and/or
@@ -27 +27 @@
   (cdr bytespec))
 
-(defun ldb (bytespec n)
-  (logand (ash n (- (byte-position bytespec)))
+(defun ldb (bytespec integer)
+  (logand (ash integer (- (byte-position bytespec)))
           (1- (ash 1 (byte-size bytespec)))))
 
-(defun ldb-test (bytespec n)
-  (not (zerop (ldb bytespec n))))
+(defun ldb-test (bytespec integer)
+  (not (zerop (ldb bytespec integer))))
+
+(defun dpb (newbyte bytespec integer)
+  (let* ((size (byte-size bytespec))
+         (position (byte-position bytespec))
+         (mask (1- (ash 1 size))))
+    (logior (logand integer (lognot (ash mask position)))
+      (ash (logand newbyte mask) position))))