On Tue, 10 Nov 2009 15:46:10 +0000, Grant Edwards wrote: > On 2009-11-10, Rhodri James <rho...@wildebst.demon.co.uk> wrote: >> On Sun, 08 Nov 2009 19:45:31 -0000, Terry Reedy <tjre...@udel.edu> >> wrote: >> >>> I believe the use of tagged pointers has been considered and so far >>> rejected by the CPython developers. And no one else that I know of has >>> developed a fork for that. It would seem more feasible with 64 bit >>> pointers where there seem to be spare bits. But CPython will have to >>> support 32 bit machines for several years. >> >> I've seen that mistake made twice (IBM 370 architecture (probably 360 >> too, I'm too young to have used it) and ARM2/ARM3). I'd rather not see >> it a third time, thank you. > > MacOS applications made the same mistake on the 68K. They reserved the > high-end bits in a 32-bit pointer and used them to contain > meta-information.
Obviously that was their mistake. They should have used the low-end bits for the metadata, instead of the more valuable high-end. High-end-is-always-better-right?-ly y'rs, -- Steven -- http://mail.python.org/mailman/listinfo/python-list
