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

Details
Type:
Enhancement
Submit Date:
2001-08-23
Status:
Resolved
Updated Date:
2003-08-15
Project Name:
JDK
Resolved Date:
2003-08-15
Component:
core-libs
OS:
solaris_7,generic,windows_2000
Sub-Component:
java.lang
CPU:
x86,sparc,generic
Priority:
P4
Resolution:
Fixed
Affected Versions:
1.4.0,1.4.1,5.0
Fixed Versions:
5.0

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

Sub Tasks

Description

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) 
======================================================================

Comments
CONVERTED DATA

BugTraq+ Release Management Values

COMMIT TO FIX:
tiger

FIXED IN:
tiger

INTEGRATED IN:
tiger
tiger-b16
2004-06-14 
WORK AROUND



Name: bsC130419			Date: 08/23/2001


write functions for these
======================================================================
2004-06-11 
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
2003-04-23


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