Bug ID: JDK-4495754 Add library support for common bit manipulation operations

Type: Enhancement
Component: core-libs
Sub-Component: java.lang
Affected Version: 1.4.0,1.4.1,5.0

Priority: P4
Status: Resolved
Resolution: Fixed
OS: generic,solaris_7,windows_2000
CPU: generic,x86,sparc

Submitted: 2001-08-23
Updated: 2017-05-16
Resolved: 2003-08-15

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5.0 tigerFixed


Name: bsC130419			Date: 08/23/2001

Java adds the arithmetic shift operator, but roll and count leading zeros would
be very nice intrinsic routines (bytecodes anyone).   These are very important
for bit-twidling, and have fast processor-specific equivalents on most
processors.
(Review ID: 130571) 
======================================================================

CONVERTED DATA BugTraq+ Release Management Values COMMIT TO FIX: tiger FIXED IN: tiger INTEGRATED IN: tiger tiger-b16

14-06-2004

WORK AROUND Name: bsC130419 Date: 08/23/2001 write functions for these ======================================================================

11-06-2004

EVALUATION It certainly is NOT worthy of a byte code. Might be worth a library routine. ###@###.### 2001-10-23 We intend to add a fairly complete set of "bit-twiddling" methods to Integer and perhaps Long in the next major release (code-named "Tiger"). In addition to the requested methods, this set might include count one bits (AKA population count), get leading one bit, count trailing zeros and get trailing one bit. Other suggestions welcome. ###@###.### 2001-10-23 Byte swapping routines for shorts, ints, and longs would be useful for New I/O and could be intrinsified down to one or two machine instructions on most processors we support. Putting such routines in the public API would be beneficial to customers. ###@###.### 2003-04-23

23-04-2003

Duplicate :	JDK-4823675 - Methods for ultra-fast bit manipulation (rotate, count bits, find bit, DSP etc.)
Duplicate :	JDK-4736393 - Please promote BigInteger.bitCnt to Integer or Math and make it public
Duplicate :	JDK-4967876 - provide bit-count method for int/long
Relates :	JDK-4900166 - static fields in java.lang wrappers for byte sizes (useful for NIO buffers)
Relates :	JDK-4210457 - Package literals? EG: Integer.NUMBEROFBITS
Relates :	JDK-4850194 - (C1) Intrinsics for operations used in crypto