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Re: [PATCH 2/2] gdb/doublest.c: Use frexpl rather than ldfrexp.
- From: Mark Kettenis <mark dot kettenis at xs4all dot nl>
- To: will dot newton at linaro dot org
- Cc: gdb-patches at sourceware dot org, patches at linaro dot org
- Date: Fri, 14 Jun 2013 14:52:59 +0200 (CEST)
- Subject: Re: [PATCH 2/2] gdb/doublest.c: Use frexpl rather than ldfrexp.
- References: <51BB0DAE dot 2070504 at linaro dot org>
> Date: Fri, 14 Jun 2013 13:33:50 +0100
> From: Will Newton <will.newton@linaro.org>
>
> Most modern systems have frexpl and gnulib provides an implementation
> for those that don't, so use it instead of the generic but inaccurate
> ldfrexp.
Great! Hopefully somebody with more gnulib experience can approve the
other diff.
> gdb/ChangeLog:
>
> 2013-06-14 Will Newton <will.newton@linaro.org>
>
> * doublest.c (ldfrexp): Remove function.
> (convert_doublest_to_floatformat): Call frexpl instead of
> ldfrexp.
> ---
> gdb/doublest.c | 49 +------------------------------------------------
> 1 file changed, 1 insertion(+), 48 deletions(-)
>
> diff --git a/gdb/doublest.c b/gdb/doublest.c
> index 9ddc7a6..2e4c87e 100644
> --- a/gdb/doublest.c
> +++ b/gdb/doublest.c
> @@ -336,53 +336,6 @@ put_field (unsigned char *data, enum floatformat_byteorders order,
> }
> }
>
> -#ifdef HAVE_LONG_DOUBLE
> -/* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR.
> - The range of the returned value is >= 0.5 and < 1.0. This is equivalent to
> - frexp, but operates on the long double data type. */
> -
> -static long double ldfrexp (long double value, int *eptr);
> -
> -static long double
> -ldfrexp (long double value, int *eptr)
> -{
> - long double tmp;
> - int exp;
> -
> - /* Unfortunately, there are no portable functions for extracting the
> - exponent of a long double, so we have to do it iteratively by
> - multiplying or dividing by two until the fraction is between 0.5
> - and 1.0. */
> -
> - if (value < 0.0l)
> - value = -value;
> -
> - tmp = 1.0l;
> - exp = 0;
> -
> - if (value >= tmp) /* Value >= 1.0 */
> - while (value >= tmp)
> - {
> - tmp *= 2.0l;
> - exp++;
> - }
> - else if (value != 0.0l) /* Value < 1.0 and > 0.0 */
> - {
> - while (value < tmp)
> - {
> - tmp /= 2.0l;
> - exp--;
> - }
> - tmp *= 2.0l;
> - exp++;
> - }
> -
> - *eptr = exp;
> - return value / tmp;
> -}
> -#endif /* HAVE_LONG_DOUBLE */
> -
> -
> /* The converse: convert the DOUBLEST *FROM to an extended float and
> store where TO points. Neither FROM nor TO have any alignment
> restrictions. */
> @@ -466,7 +419,7 @@ convert_doublest_to_floatformat (CONST struct floatformat *fmt,
> }
>
> #ifdef HAVE_LONG_DOUBLE
> - mant = ldfrexp (dfrom, &exponent);
> + mant = frexpl (dfrom, &exponent);
> #else
> mant = frexp (dfrom, &exponent);
> #endif
> --
> 1.8.1.4
>
>