• Norm (4/4) Jul 31 2004 Does Digital Mars support 80-bit long doubles (like Borland)? If it does...
• Walter (6/11) Jul 31 2004 Yes.
• Gisle Vanem (17/20) Aug 02 2004 DMC does support it, but only under Win32. See for definitions...

Norm <Norm_member pathlink.com> writes:

Does Digital Mars support 80-bit long doubles (like Borland)? If it does, the
"How Data is Stored" section of the "Compiler & Tools Guide Help is wrong: it
says long doubles are 64 bits.

Norm

"Walter" <newshound digitalmars.com> writes:

"Norm" <Norm_member pathlink.com> wrote in message
news:cehsr7$1nh1$1 digitaldaemon.com...
 Does Digital Mars support 80-bit long doubles

Yes.

 (like Borland)?

I don't know how Borland does it.

 If it does, the
 "How Data is Stored" section of the "Compiler & Tools Guide Help is wrong:

it
 says long doubles are 64 bits.

That obviously needs fixing <g>.

"Gisle Vanem" <giva users.sourceforge.net> writes:

"Norm" <Norm_member pathlink.com> wrote:

 Does Digital Mars support 80-bit long doubles (like Borland)? If it does, the
 "How Data is Stored" section of the "Compiler & Tools Guide Help is wrong: it
 says long doubles are 64 bits.

DMC does support it, but only under Win32. See <float.h> for definitions. 
Borland vs DMC use the same layout for long doubles. How could they *not* 
do? Most of the calculations are done in silicon, so Intel and it's IEEE 
standard has set the scene here.

From DMC's <float.h>:
#define LDBL_MIN        0x1p-16382L
#define LDBL_MIN_10_EXP -4932

and Borland:
#define LDBL_MIN            _tiny_ldble
#define LDBL_MIN_10_EXP     -4931

Someone is off by one here, but probably doesn't matter; the exponent
is already 14 bits in long doubles AFAICR.

But I don't understand why Borland uses an extern var instead of a 
constant LDBL_MIN etc. Avoiding inline  math comparisons, linker 
problems?

--gv