Re: HPGCC related ...

On Mar 20, 3:04 am, Claudio Lapilli <pleasedonts...@xxxxxxx> wrote:

Even MS abandoned the long double years ago (at least on the x86
platform, don't know on others), and now long double is mapped to
double, to add more confusion.

I seem to recall that this happened when they moved to the 32-bit
Windows compiler, probably with Windows-95. It seemed a shame not to
take advantage of the 80-bit floating point hardware that was there
for the using. At the time, I was doing a lot of fractal
programming. Using 80-bit floats instead of 64-bit allowed a few more
zooms before having to resort to slower software code.

Your comment got me curious about which x86 compilers still support
the 80-bit long doubles. Of the current compilers that I could get me
hands on: gcc (and variants like Cygwin, MinGW), Intel, Digital Mars,
and Turbo C++ (it's back) all support 80-bit long doubles in hardware;
MS and Open Watcom do not.

I gather that ARM gcc only goes up to 64-bit floats, so it makes sense
for hpgcc to do the same.

This brings to mind what may be a silly question, but please pardon my
ignorance. I know there is a _lot_ of code in hpgcc that is specific
to the 49g+/50g. But there is also a lot that is standard to any C
compiler (math libraries, std i/o, etc.). How much of ARM gcc's
standard library had to be rewritten for hpgcc? For instance, the
scanf() function that we've been discussing. Was there already a
glibc scanf() for ARM, or did this have to be written from scratch? I
see from the source code that some of the fast IEEE math routines are
present while others are not (such as hyperbolics, expm1, log1p).
Would these have to be written from scratch, or do they exist in an
ARM glibc? Can you just recompile glibc (with a few tweaks for the
mixed endian floats), or am I oversimplifying the process?

Thanks for any insights you can pass my way.
-wes
.

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