Commit Graph

3 Commits

Author SHA1 Message Date
Joseph Myers
f7a9f785e5 Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
Joseph Myers
6ace393821 Fix pow missing underflows (bug 18825).
Similar to various other bugs in this area, pow functions can fail to
raise the underflow exception when the result is tiny and inexact but
one or more low bits of the intermediate result that is scaled down
(or, in the i386 case, converted from a wider evaluation format) are
zero.  This patch forces the exception in a similar way to previous
fixes, thereby concluding the fixes for known bugs with missing
underflow exceptions currently filed in Bugzilla.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #18825]
	* sysdeps/i386/fpu/i386-math-asm.h (FLT_NARROW_EVAL_UFLOW_NONNAN):
	New macro.
	(DBL_NARROW_EVAL_UFLOW_NONNAN): Likewise.
	(LDBL_CHECK_FORCE_UFLOW_NONNAN): Likewise.
	* sysdeps/i386/fpu/e_pow.S: Use DEFINE_DBL_MIN.
	(__ieee754_pow): Use DBL_NARROW_EVAL_UFLOW_NONNAN instead of
	DBL_NARROW_EVAL, reloading the PIC register as needed.
	* sysdeps/i386/fpu/e_powf.S: Use DEFINE_FLT_MIN.
	(__ieee754_powf): Use FLT_NARROW_EVAL_UFLOW_NONNAN instead of
	FLT_NARROW_EVAL.  Use separate return path for case when first
	argument is NaN.
	* sysdeps/i386/fpu/e_powl.S: Include <i386-math-asm.h>.  Use
	DEFINE_LDBL_MIN.
	(__ieee754_powl): Use LDBL_CHECK_FORCE_UFLOW_NONNAN, reloading the
	PIC register.
	* sysdeps/ieee754/dbl-64/e_pow.c (__ieee754_pow): Use
	math_check_force_underflow_nonneg.
	* sysdeps/ieee754/flt-32/e_powf.c (__ieee754_powf): Force
	underflow for subnormal result.
	* sysdeps/ieee754/ldbl-128/e_powl.c (__ieee754_powl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Use
	math_check_force_underflow_nonneg.
	* sysdeps/x86/fpu/powl_helper.c (__powl_helper): Use
	math_check_force_underflow.
	* sysdeps/x86_64/fpu/x86_64-math-asm.h
	(LDBL_CHECK_FORCE_UFLOW_NONNAN): New macro.
	* sysdeps/x86_64/fpu/e_powl.S: Include <x86_64-math-asm.h>.  Use
	DEFINE_LDBL_MIN.
	(__ieee754_powl): Use LDBL_CHECK_FORCE_UFLOW_NONNAN.
	* math/auto-libm-test-in: Add more tests of pow.
	* math/auto-libm-test-out: Regenerated.
2015-09-25 22:29:10 +00:00
Joseph Myers
b2a64460ba Refactor x86_64 libm code forcing underflow exceptions.
This patch refactors code in sysdeps/x86_64/fpu that forces underflow
exceptions and closely follows corresponding i386 code to use common
macros in x86_64-math-asm.h for that purpose.  This is mainly about
keeping the code similar to the i386 code as far as possible, since
each macro apart from DEFINE_LDBL_MIN ends up used only once.  It
would be possible to do a further refactoring to share these macros
between i386 and x86_64 (with i386 using the fcomip / fucomip versions
when building for i686 and above), but I have no immediate plans to do
so.

Tested for x86_64.

	* sysdeps/x86_64/fpu/x86_64-math-asm.h: New file.
	* sysdeps/x86_64/fpu/e_exp2l.S: Include <x86_64-math-asm.h>.
	(ldbl_min): Replace with use of DEFINE_LDBL_MIN.
	(__ieee754_exp2l): Use LDBL_CHECK_FORCE_UFLOW_NONNEG_NAN.
	* sysdeps/x86_64/fpu/e_expl.S: Include <x86_64-math-asm.h>.
	[!USE_AS_EXPM1L] (cmin): Replace with use of DEFINE_LDBL_MIN.
	(IEEE754_EXPL): Use LDBL_CHECK_FORCE_UFLOW_NONNEG.
2015-09-24 22:25:30 +00:00