On Friday, 05/25/2018 at 08:51 GMT, Mark Post <[email protected]> wrote: > >>> On 5/23/2018 at 01:25 PM, Alan Altmark <[email protected]> wrote: > > While Paul doesn't need to express the value of AM32 (it's obvious) > > Not to me.
4 GiB address space without increasing the space needed to store registers. Twice as much memory with no runtime performance hit. Motherhood, apple pie, puppies, kittens, and babies. 4 > 2. What's not to like? Unfortunately it comes with baggage too heavy to be ignored, most of which has been mentioned. The performance benefit of "compactness" isn't worth (IMO) the breakage that comes with it. Under laboratory conditions you can create 32-bit programs with AM64. They just can't (generally) deal with 31-bit APIs, something they must use to get the benefit of 32-bit registers. If I have to jump through hoops to break my 4 GiB address space in half so I can call 31-bit APIs, all the value leaks away. Alan Altmark Senior Managing z/VM and Linux Consultant IBM Systems Lab Services IBM Z Delivery Practice ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 [email protected] IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
