dmd platform support - poll

Andrei Alexandrescu SeeWebsiteForEmail at
Sat Dec 27 15:30:43 PST 2008

Nick Sabalausky wrote:
> "Derek Parnell" <derek at psych.ward> wrote in message 
> news:nkr1wyvyj3vv$.qr1gd1h779fx.dlg at
>> On Sat, 27 Dec 2008 15:45:57 -0500, Nick Sabalausky wrote:
>>> ... judging by number of people here asking for
>>> 64-bit, I find it highly unlikely that most of them have plans to work on
>>> such things either.
>> My interest in 64-bit hardware support is based on the belief that before
>> too long, buying a new 32-bit platform might be a difficult thing to do.
>> Five years from now, I don't want to be forced into finding a good
>> second-hand machine just so I can work with D.
> I don't want to be forced into buying a new 64-bit machine just because a 
> whole bunch of "gotta have the faciest stuff out there" people have deemed 
> 32-bit insufficient for all computing needs. Besides, can't 64-bit machines 
> run 32-bit code? 

Related: a rant of Knuth to be found at

A Flame About 64-bit Pointers

It is absolutely idiotic to have 64-bit pointers when I compile a 
program that uses less than 4 gigabytes of RAM. When such pointer values 
appear inside a struct, they not only waste half the memory, they 
effectively throw away half of the cache.

The gcc manpage advertises an option "-mlong32" that sounds like what I 
want. Namely, I think it would compile code for my x86-64 architecture, 
taking advantage of the extra registers etc., but it would also know 
that my program is going to live inside a 32-bit virtual address space.

Unfortunately, the -mlong32 option was introduced only for MIPS 
computers, years ago. Nobody has yet adopted such conventions for 
today's most popular architecture. Probably that happens because 
programs compiled with this convention will need to be loaded with a 
special version of libc.

Please, somebody, make that possible.

In my opinion, it's not application pressure that drives 64-bit machine 
adoption, now or in the near future. It's RAM price, availability, and 
usefulness. A 32-bit machine cannot gainfully have more than 4GB of RAM, 
period. That's an awful limitation in wake of increased OS and 
application demands and falling RAM prices. So people don't migrate to 
64 bits just because a whole bunch of "gotta have the fanciest stuff out 
there". They migrate (often without even knowing it) just because they 
want more RAM. And they want more RAM because machines with more RAM 
often run smoother and faster.


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