Re: is real*8 a standard declaration style?

On 10/31/2011 1:21 AM, Steven G. Kargl wrote:
On Mon, 31 Oct 2011 00:06:59 -0500, Robert Miles wrote:

On 10/29/2011 7:59 AM, Daniel Carrera wrote:
On 10/29/2011 02:14 PM, Jinsong Zhao wrote:
[snip]
! Extended precision (80 format for for Intel CPUs). integer, parameter
:: extn = selected_real_kind(18)


Cheers,
Daniel.

You might want to check if that still applies. The last I knew, the
older Intel CPUs that used a separate FPU chip had the 80-bit format,
but the newer ones with the CPU and the FPU on the same chip didn't.


Nope. Any chip that supports the i387 instruction set has the
80-bit Intel format available. This includes a large selection
of single chip cpu+fpu products from Intel, AMD, and licensees.

Windows libraries, however, don't support 80-bit format, and 32-bit applications using those libraries are expected to set 53-bit precision. The X64 Windows sets 53-bit precision before launching an application.
Intel compilers (even on linux) make an application by default which sets 53-bit precision.
So it's likely that many people haven't used 64-bit precision/80-bit format for years. As Steven pointed out, the hardware continues to support it.

--
Tim Prince
.

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