When 31-bit addressing became available, that vast, new OCEAN of storage above the line was available to be used as a cache.
First Assembler programs that used floating point instructions had to be specially written. Then those that used 31-bit addressing had to be specially written. Then special writing was necessary for using data spaces, serializing on a full- or double-word on multi-processors, using the coupling facility, DIV, running in a cross-memory mode, etc. Every time new instructions and new technologies are introduced, those who wish to use that which is new have to write special instructions in their Assembler programs. Bill Fairchild Programmer Rocket Software 408 Chamberlain Park Lane * Franklin, TN 37069-2526 * USA t: +1.617.614.4503 * e: [email protected] * w: www.rocketsoftware.com -----Original Message----- From: IBM Mainframe Assembler List [mailto:[email protected]] On Behalf Of Tom Marchant Sent: Friday, September 14, 2012 8:24 AM To: [email protected] Subject: Re: Data spaces vs hiperspaces On Thu, 13 Sep 2012 18:10:01 +0000, David Stokes wrote: >In z/OS 64 bit storage is just a sort of data cache really. No, it isn't, but it can be used that way. >Programs that use it have to be specially written, Of course they do. That's because new instructions must be used to manipulate the registers required to address the data. It was designed that way for compatibility with old code. >it's not a (more or less) transparent thing like in Windows (just >recompile with the 64 bit option!) Is that true of assembler programs in Windows? If your programs are in C/C++, you can do that in z/Architecture too. -- Tom Marchant
