On Fri, 9 Nov 2007 08:10:31 -0600 Mohammad Khan <[EMAIL PROTECTED]> wrote:
:>Interesting evolution of 24 - 31 - 64 bit addressing : :> - 16MB is a real euclidian "line" i.e. zero thickness. :> - 2GB "line" has a thickness of 4KB :> - Now the bar is 2GB wide. :>As for the need of a "guaranteed bad address", is it something similar to a :>NULL pointer in C ? If I recall correctly, C implemets NULL pointers as X'0' :>which off course would run into issues with PSA access here. By the way how :>was this need satisfied in 24 bit days ? Or was it that the need hadn't arisen :>yet ? It is a need for a pointer with a "bad" value, one that guarantees a failure if not checked for validity. It is a safety net. 0 or X'80000000' in 24/31 bit mode does not do the job, since location 0 can be freely fetched. -- Binyamin Dissen <[EMAIL PROTECTED]> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
