Fix strtod rounding (bug 3479)

[Joseph S. Myers]

On Tue, 14 Aug 2012, Roland McGrath wrote:

> If there's generated source, even if it never really needs to be
> regenerated again, I think we should have the generator programs
> in the source tree.

This version, again relative to a tree with my strtod integer overflow
patch <http://sourceware.org/ml/libc-alpha/2012-08/msg00202.html>
(pending review) applied, includes the generators and input file in
the source tree, with comments on the generated tables pointing to the
generators, but is otherwise unchanged.

2012-08-15  Joseph Myers  <joseph@codesourcery.com>

	[BZ #3479]
	* stdlib/strtod_l.c (NDIG): Remove.
	(HEXNDIG): Likewise.
	(MPNSIZE): Increase to represent 10^n where 2^-n is 1/4 ulp of the
	smallest representable value.
	(____STRTOF_INTERNAL): Use all fractional decimal digits that may
	lie within an exact representation of 1/2 ulp of the result.
	* stdlib/fpioconst.c (__tens): Include 10^2^9 and 10^2^10
	unconditionally.
	(TENS_P9_IDX): Define unconditionally.
	(TENS_P9_SIZE): Likewise.
	(TENS_P10_IDX): Likewise.
	(TENS_P10_SIZE): Likewise.
	[BITS_PER_MP_LIMB == 32]: Change condition for larger powers of 10
	to !defined __NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024.
	[!__NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024] (__tens): Add
	entries for 10^2^13 and 10^2^14.
	[!__NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024]
	(TENS_P13_IDX): Define.
	(TENS_P13_SIZE): Likewise.
	(TENS_P14_IDX): Likewise.
	(TENS_P14_SIZE): Likewise.
	(_fpioconst_pow10): Change array size to
	FPIOCONST_POW10_ARRAY_SIZE.  Make entries for 10^2^9 and 10^2^10
	unconditional.
	(_fpioconst_pow10) [!__NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ >
	1024]: Add entries for 10^2^13 and 10^2^14.
	[LAST_POW10 > _LAST_POW10]: Remove #error.
	* stdlib/fpioconst.h (FPIOCONST_POW10_ARRAY_SIZE): Define.
	(_fpioconst_pow10): Change array size to
	FPIOCONST_POW10_ARRAY_SIZE.
	* stdlib/gen-fpioconst.c: New file.
	* stdlib/gen-tst-strtod-round.c: Likewise.
	* stdlib/tst-strtod-round-data: Likewise.
	* stdlib/tst-strtod-round.c: Likewise.
	* stdlib/Makefile (tests): Add tst-strtod-round.

(Patch itself attached gzipped because of its size.)

-- 
Joseph S. Myers
joseph@codesourcery.com
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