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digitalmars.D - strtold usage in DMD front end

reply James Dunne <james.jdunne gmail.com> writes:
Just recently I discovered the usage of the strtold() function in the numeric
literal parsing inside the DMD front end.  strtold() parses a string and returns
a long double representation (80-bit floating point).

I run Linux on a Mini-ITX system from VIA (EPIA Nehemiah M10000 CPU) and my own
tests of using strtold() in C programs report incorrect and bizarre results
every time.  I guess that's just a limitation of the VIA chipset... However, DMD
seems to work fine (read parse numbers correctly) on the same system.  What
gives??  Is there some magic going on in DMD for Linux?

Regards,
James Dunne
Jun 09 2005
next sibling parent reply Sean Kelly <sean f4.ca> writes:
In article <d89ef6$1df8$1 digitaldaemon.com>, James Dunne says...

Just recently I discovered the usage of the strtold() function in the numeric
literal parsing inside the DMD front end.  strtold() parses a string and returns
a long double representation (80-bit floating point).

I run Linux on a Mini-ITX system from VIA (EPIA Nehemiah M10000 CPU) and my own
tests of using strtold() in C programs report incorrect and bizarre results
every time.  I guess that's just a limitation of the VIA chipset... However, DMD
seems to work fine (read parse numbers correctly) on the same system.  What
gives??  Is there some magic going on in DMD for Linux?


Probably a stupid question, but are you inspecting the full 80 bits to verify
the value?  And I thought the non-Windows compiler was GDC, or are you running
this with WINE?


Sean
Jun 09 2005
next sibling parent reply James Dunne <james.jdunne gmail.com> writes:
In article <d89j46$1irb$1 digitaldaemon.com>, Sean Kelly says...

In article <d89ef6$1df8$1 digitaldaemon.com>, James Dunne says...

Just recently I discovered the usage of the strtold() function in the numeric
literal parsing inside the DMD front end.  strtold() parses a string and returns
a long double representation (80-bit floating point).

I run Linux on a Mini-ITX system from VIA (EPIA Nehemiah M10000 CPU) and my own
tests of using strtold() in C programs report incorrect and bizarre results
every time.  I guess that's just a limitation of the VIA chipset... However, DMD
seems to work fine (read parse numbers correctly) on the same system.  What
gives??  Is there some magic going on in DMD for Linux?


Probably a stupid question, but are you inspecting the full 80 bits to verify
the value?  And I thought the non-Windows compiler was GDC, or are you running
this with WINE?


Sean


No, DMD is available for both Win32 and Linux straight from Walter.  It is not
GDC.

Personally I haven't tested the 80-bit long double support for the Mini-ITX
system, but DMD works fine on it.  I was intrigued to see my own tests for
strtold() written in C fail on the system, while similar code in DMD works!

Regards,
James Dunne
Jun 09 2005
parent "Unknown W. Brackets" <unknown simplemachines.org> writes:
IIRC, something is said in the documentation about proper support of 80 
bit floating point numbers...

-[Unknown]



 In article <d89j46$1irb$1 digitaldaemon.com>, Sean Kelly says...
 

In article <d89ef6$1df8$1 digitaldaemon.com>, James Dunne says...


Just recently I discovered the usage of the strtold() function in the numeric
literal parsing inside the DMD front end.  strtold() parses a string and returns
a long double representation (80-bit floating point).

I run Linux on a Mini-ITX system from VIA (EPIA Nehemiah M10000 CPU) and my own
tests of using strtold() in C programs report incorrect and bizarre results
every time.  I guess that's just a limitation of the VIA chipset... However, DMD
seems to work fine (read parse numbers correctly) on the same system.  What
gives??  Is there some magic going on in DMD for Linux?


Probably a stupid question, but are you inspecting the full 80 bits to verify
the value?  And I thought the non-Windows compiler was GDC, or are you running
this with WINE?


Sean


 
 
 No, DMD is available for both Win32 and Linux straight from Walter.  It is not
 GDC.
 
 Personally I haven't tested the 80-bit long double support for the Mini-ITX
 system, but DMD works fine on it.  I was intrigued to see my own tests for
 strtold() written in C fail on the system, while similar code in DMD works!
 
 Regards,
 James Dunne
Jun 09 2005
prev sibling parent reply clayasaurus <clayasaurus gmail.com> writes:
Sean Kelly wrote:

 In article <d89ef6$1df8$1 digitaldaemon.com>, James Dunne says...
 

Just recently I discovered the usage of the strtold() function in the numeric
literal parsing inside the DMD front end.  strtold() parses a string and returns
a long double representation (80-bit floating point).

I run Linux on a Mini-ITX system from VIA (EPIA Nehemiah M10000 CPU) and my own
tests of using strtold() in C programs report incorrect and bizarre results
every time.  I guess that's just a limitation of the VIA chipset... However, DMD
seems to work fine (read parse numbers correctly) on the same system.  What
gives??  Is there some magic going on in DMD for Linux?


 
 
 Probably a stupid question, but are you inspecting the full 80 bits to verify
 the value?  And I thought the non-Windows compiler was GDC, or are you running
 this with WINE?
 
 
 Sean
 
 


To clear up some confusion you might have, GDC allows D to be run on 
FreeBSD, MacOS, and any other OS that can use gcc as the compiler. You 
could run GDC on linux, but since Walter already provides a linux 
version, I don't think there is much reason to run GDC on linux.
Jun 09 2005
next sibling parent Sean Kelly <sean f4.ca> writes:
In article <d89tgi$1ta3$1 digitaldaemon.com>, clayasaurus says...

To clear up some confusion you might have, GDC allows D to be run on 
FreeBSD, MacOS, and any other OS that can use gcc as the compiler. You 
could run GDC on linux, but since Walter already provides a linux 
version, I don't think there is much reason to run GDC on linux.


Thanks.  I suppose that explains the *nix binaries that are in the bin directory
:p

I don't suppose anyone has tried GDC under WinSFU?  I've been meaning to, but
haven't gotten around to it yet.


Sean
Jun 09 2005
prev sibling parent =?ISO-8859-1?Q?Anders_F_Bj=F6rklund?= <afb algonet.se> writes:
clayasaurus wrote:


 To clear up some confusion you might have, GDC allows D to be run on 
 FreeBSD, MacOS, and any other OS that can use gcc as the compiler. You 
 could run GDC on linux, but since Walter already provides a linux 
 version, I don't think there is much reason to run GDC on linux.


Where "linux" for DMD means: a sufficiently new version of Linux X86...
GDC also works on older Linux for X86, as well as Linux PPC (and others)

Another difference is that GDC is Free Software (GPL), where DMD is not.
This is another reason to run GDC on Linux, like for trying patches out?

--anders
Jun 09 2005
prev sibling parent "Walter" <newshound digitalmars.com> writes:
"James Dunne" <james.jdunne gmail.com> wrote in message
news:d89ef6$1df8$1 digitaldaemon.com...

 Just recently I discovered the usage of the strtold() function in the


numeric

 literal parsing inside the DMD front end.  strtold() parses a string and


returns

 a long double representation (80-bit floating point).

 I run Linux on a Mini-ITX system from VIA (EPIA Nehemiah M10000 CPU) and


my own

 tests of using strtold() in C programs report incorrect and bizarre


results

 every time.  I guess that's just a limitation of the VIA chipset...


However, DMD

 seems to work fine (read parse numbers correctly) on the same system.


What

 gives??  Is there some magic going on in DMD for Linux?


The likely source of the difference is that dmd is compiled on my Linux box
with whatever strtold is in the C runtime library on *my* box. When you use
the dmd binary, you're running the strtold from my box. But when you build
an app using strtold, you're using the strtold from *your* box, which might
be broken.

BTW, my Linux box is using a VIA chip.
Jun 12 2005