[Linux-ia64] ILP32 support?

[Linux-ia64] ILP32 support?

[Vadim Furman]

Are there any plans to support ILP32 mode?

Vadim Furman

Re: [Linux-ia64] ILP32 support?

[Don Dugger]

Also, there would have to be some changes to the kernel.  This would
create ELF64 processes that have to live within the first 4G of
memory.  We already support 32-bit processes but some kernel changes
would be required to identify this new entity.

On Tue, Feb 22, 2000 at 03:08:54PM -0800, David Mosberger wrote:
> >>>>> On Tue, 22 Feb 2000 14:21:14 -0800, "Vadim Furman" <vadimf@mainsoft.com> said:
> 
>   Vadim> Are there any plans to support ILP32 mode?  Vadim Furman
> 
> No.  So far, nobody has felt that the (small) benefits of ILP32 are
> worth its trouble.  No kernel mods would be required, but you'd have
> to create a completely new user-level environment (new compiler, new
> header files, all libraries would have to be recompiled with ILP32
> mode, etc.).
> 
> 	--david
> 
> 
> _______________________________________________
> Linux-IA64 mailing list
> Linux-IA64@linuxia64.org
> http://lists.linuxia64.org/lists/listinfo/linux-ia64

-- 
Don Dugger
"Censeo Toto nos in Kansa esse decisse." - D. Gale
n0ano@valinux.com
Ph: 303/938-9838

Re: [Linux-ia64] ILP32 support?

[David Mosberger]

>>>>> On Tue, 22 Feb 2000 14:21:14 -0800, "Vadim Furman" <vadimf@mainsoft.com> said:

  Vadim> Are there any plans to support ILP32 mode?  Vadim Furman

No.  So far, nobody has felt that the (small) benefits of ILP32 are
worth its trouble.  No kernel mods would be required, but you'd have
to create a completely new user-level environment (new compiler, new
header files, all libraries would have to be recompiled with ILP32
mode, etc.).

	--david

Re: [Linux-ia64] ILP32 support?

[David Mosberger]

>>>>> On Tue, 22 Feb 2000 16:01:41 -0700, Don Dugger <n0ano@valinux.com> said:

  Don> Also, there would have to be some changes to the kernel.  This
  Don> would create ELF64 processes that have to live within the first
  Don> 4G of memory.  We already support 32-bit processes but some
  Don> kernel changes would be required to identify this new entity.

Actually, the forthcoming kernel patch already has a per-process
mmap-base.  So the only change required in the kernel would be to
recognize ILP32 binaries and set the mmap-base accordingly (so, yeah,
I lied when I said no changes would be required... ;-).  (This doesn't
mean that I think ILP32 support is a good idea...)

	--david

RE: [Linux-ia64] ILP32 support?

[Vadim Furman]

>
>   Vadim> Are there any plans to support ILP32 mode?  Vadim Furman
>
> No.  So far, nobody has felt that the (small) benefits of ILP32 are
> worth its trouble.
IMHO benefits of ILP32 are huge, since you can relatively simply port
existing 32 apps to ia64 and in the same time enjoy the perfomance of the
new chip.
Is it possible to force LP64 processes below 4G? Is there a compiler/linker
switch to do so?

RE: [Linux-ia64] ILP32 support?

[David Mosberger]

>>>>> On Tue, 22 Feb 2000 16:11:53 -0800, "Vadim Furman" <vadimf@mainsoft.com> said:

  Vadim> IMHO benefits of ILP32 are huge, since you can relatively
  Vadim> simply port existing 32 apps to ia64 and in the same time
  Vadim> enjoy the perfomance of the new chip.

If it's not a performance critical program, you might just as well
leave it an x86 binary and do no porting at all.  If it's a
performance critical program, then it's probably worthwhile to make it
64-bit clean (which isn't hard) and get the benefit of wide arithmetic
and assurance that the program can deal with 64-bit files, address
spaces, and y2038 without any problem at all.

  Vadim> Is it possible to force LP64 processes below 4G? Is there a
  Vadim> compiler/linker switch to do so?

You can use a linker script to force things below 4GB.  For mmap,
you'd need to change the kernel to push the mmap base below 4GB.
You'll be on your own though if you do this.  All open source programs
I know of are 64-bit clean so the incentive for the open source
community to support ILP32 is very small.

	--david

Re: [Linux-ia64] ILP32 support?

[Rich Altmaier]

I would like to express real concern with this proposal.  We went down this
path with IRIX on the MIPS processor.  
The situation is:  We are asking ISVs to generate native IA64 binaries.  
If there are two formats of such
binaries, and they are not link compatible, now any ISV failing to release
both formats will cause a terrible fragmentation.  Any given user will not
be sure of being able to find link compatible stuff for their needs.  This
is a terrible inhibitor to the spread of software, not to mention creating
dual libraries for all IA64 stuff (ok guys, where are you going to put these
new libs?  This is a new ABI you understand!!!).

But perhaps you were not suggesting this.  I believe Microsoft has defined
a special form of native 64bit-address IA64 code, called "the sandbox", where
the linker and kernel simply assign all addresses below say 2Gbyte.  This
code still contains 64bit pointer types, but it has no actual values exceeding
32bit container.  Hence sloppy code converting pointers to say ints doesn't
lose bits.  But the pointer data type still changes size to 64bits, hence porting
is not 0 effort.  I'm not clear on the linkage compatibility issues here.

I would implore you to not issue such buggy code.   Please make your code
64bit-address clean.  Please don't split the IA64 marketplace!!!!!!!!!

Thanks, Rich


Vadim Furman wrote:
> 
> >
> >   Vadim> Are there any plans to support ILP32 mode?  Vadim Furman
> >
> > No.  So far, nobody has felt that the (small) benefits of ILP32 are
> > worth its trouble.
> IMHO benefits of ILP32 are huge, since you can relatively simply port
> existing 32 apps to ia64 and in the same time enjoy the perfomance of the
> new chip.
> Is it possible to force LP64 processes below 4G? Is there a compiler/linker
> switch to do so?
> 
> _______________________________________________
> Linux-IA64 mailing list
> Linux-IA64@linuxia64.org
> http://lists.linuxia64.org/lists/listinfo/linux-ia64

RE: [Linux-ia64] ILP32 support?

[Dan Pop]

On Tue, 22 Feb 2000, Vadim Furman wrote:

> IMHO benefits of ILP32 are huge, since you can relatively simply port
> existing 32 apps to ia64 and in the same time enjoy the perfomance of the
> new chip.

Any application assuming that sizeof(int) = sizeof(long) and/or
sizeof(int) = sizeof(type *) is broken by implementation, because
such assumptions are *never* really needed in correctly written code.
The right thing is to fix it. 

Dan