On Mon, 2013-06-03 at 11:02 -0500, Paul Gilmartin wrote: > (Probably. If an interpreter > were make its smallest unit of addressable storage 8 bytes, it could still > address 32GiB with 32 bit addresses. I doubt that Java is implemented in > that fashion.)
The IBM Java implementation does precisely this. Objects all are doubleword aligned, so the low-order three bits of a 32-bit address are zero. If you enable "compressed references" then 64-bit pointers are right-shifted into 32-bit words. (As you note this will only work for addresses below 32GiB.) It's a big win for Java heap space, because 64-bit pointers increase object size approximately 60% per Marcel Mitran. See his IBM Java on System z presentation at: http://www-06.ibm.com/software/jp/zseries/events/language2011/download/pdf/02_e.pdf -- David Andrews A. Duda & Sons, Inc. david.andr...@duda.com ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
