glibc/sysdeps/ieee754/dbl-64/s_lround.c
Joseph Myers 06d97e5e61 Fix lrint, llrint, lround, llround missing exceptions for MIPS (bug 16399).
For 32-bit MIPS and some other systems, various of the lrint, llrint,
lround, llround functions can be missing exceptions on overflow
because casts do not (in current GCC) result in the proper
exceptions.  In the MIPS case there are two problems here: MIPS I code
generation uses an assembler macro that doesn't raise exceptions,
while the libgcc conversions of floating-point values to long long
also do not raise "invalid" on all overflow cases (and can raise
spurious "inexact").

This patch adds support in the generic code (only the functions for
which this problem has actually been seen) for forcing the "invalid"
exception in the problem cases, and enables that support for the
affected MIPS cases.

Tested for MIPS; also tested for x86_64 and x86 that installed
stripped shared libraries are unchanged by this patch.

	[BZ ]
	* sysdeps/generic/fix-fp-int-convert-overflow.h: New file.
	* sysdeps/ieee754/dbl-64/s_llrint.c: Include <fenv.h>, <limits.h>
	and <fix-fp-int-convert-overflow.h>.
	(__llrint) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/dbl-64/s_llround.c: Include <fenv.h>, <limits.h>
	and <fix-fp-int-convert-overflow.h>.
	(__llround) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/dbl-64/s_lrint.c: Include
	<fix-fp-int-convert-overflow.h>.
	(__lrint) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/dbl-64/s_lround.c: Include
	<fix-fp-int-convert-overflow.h>.
	(__lround) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/flt-32/s_llrintf.c: Include <fenv.h>, <limits.h>
	and <fix-fp-int-convert-overflow.h>.
	(__llrintf) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/flt-32/s_llroundf.c: Include <fenv.h>,
	<limits.h> and <fix-fp-int-convert-overflow.h>.
	(__llroundf) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/flt-32/s_lrintf.c: Include <fenv.h>, <limits.h>
	and <fix-fp-int-convert-overflow.h>.
	(__lrintf) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/ieee754/flt-32/s_lroundf.c: Include <fenv.h>, <limits.h>
	and <fix-fp-int-convert-overflow.h>.
	(__lroundf) [FE_INVALID]: Force FE_INVALID exception as needed if
	FIX_DBL_LLONG_CONVERT_OVERFLOW.
	* sysdeps/mips/mips32/fpu/fix-fp-int-convert-overflow.h: New file.
2015-10-09 21:02:19 +00:00

114 lines
2.8 KiB
C

/* Round double value to long int.
Copyright (C) 1997-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <limits.h>
#include <math.h>
#include <math_private.h>
#include <fix-fp-int-convert-overflow.h>
long int
__lround (double x)
{
int32_t j0;
u_int32_t i1, i0;
long int result;
int sign;
EXTRACT_WORDS (i0, i1, x);
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
sign = (i0 & 0x80000000) != 0 ? -1 : 1;
i0 &= 0xfffff;
i0 |= 0x100000;
if (j0 < 20)
{
if (j0 < 0)
return j0 < -1 ? 0 : sign;
else
{
i0 += 0x80000 >> j0;
result = i0 >> (20 - j0);
}
}
else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
{
if (j0 >= 52)
result = ((long int) i0 << (j0 - 20)) | ((long int) i1 << (j0 - 52));
else
{
u_int32_t j = i1 + (0x80000000 >> (j0 - 20));
if (j < i1)
++i0;
if (j0 == 20)
result = (long int) i0;
else
{
result = ((long int) i0 << (j0 - 20)) | (j >> (52 - j0));
#ifdef FE_INVALID
if (sizeof (long int) == 4
&& sign == 1
&& result == LONG_MIN)
/* Rounding brought the value out of range. */
feraiseexcept (FE_INVALID);
#endif
}
}
}
else
{
/* The number is too large. Unless it rounds to LONG_MIN,
FE_INVALID must be raised and the return value is
unspecified. */
#ifdef FE_INVALID
if (FIX_DBL_LONG_CONVERT_OVERFLOW
&& !(sign == -1
&& (sizeof (long int) == 4
? x > (double) LONG_MIN - 0.5
: x >= (double) LONG_MIN)))
{
feraiseexcept (FE_INVALID);
return sign == 1 ? LONG_MAX : LONG_MIN;
}
else if (!FIX_DBL_LONG_CONVERT_OVERFLOW
&& sizeof (long int) == 4
&& x <= (double) LONG_MIN - 0.5)
{
/* If truncation produces LONG_MIN, the cast will not raise
the exception, but may raise "inexact". */
feraiseexcept (FE_INVALID);
return LONG_MIN;
}
#endif
return (long int) x;
}
return sign * result;
}
weak_alias (__lround, lround)
#ifdef NO_LONG_DOUBLE
strong_alias (__lround, __lroundl)
weak_alias (__lround, lroundl)
#endif