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[PATCH] [BZ #2749] soft-fp fixes, update
- From: Steven Munroe <munroesj at us dot ibm dot com>
- To: libc-alpha at sources dot redhat dot com, "Joseph S. Myers" <joseph at codesourcery dot com>, Jakub Jelinek <jakub at redhat dot com>
- Date: Fri, 12 Jan 2007 13:54:46 -0600
- Subject: [PATCH] [BZ #2749] soft-fp fixes, update
I updated this patch to current glibc cvs trunk and move fenv-libc.h to sysdeps/powerpc/nofpu/ as suggested by Jakub.
It is clear that rounding a inf or NAN makes no sense and is wasted effort, so I left the
_FP_PACK_SEMIRAW patch unchanged.
This patch corrects functional issues we found in the soft-fp implementation that are common to all arches using soft-fp. We need to get these patches into libc trunk, so we can migrate them into the soft-fp implementation of gcc mainline.
2007-01-12 Steven Munroe <sjmunroe@us.ibm.com>
Joe Kerian <jkerian@us.us.ibm.com>
[BZ #2749]
* soft-fp/op-4.h (__FP_FRAC_SUB_3, __FP_FRAC_SUB_4): Correct borrow
handling for high words.
* soft-fp/op-common.h (_FP_OVERFLOW_SEMIRAW): Always set inexact
and overflow for infinity.
(_FP_PACK_SEMIRAW): Update comment. Do not round if NaN.
* sysdeps/powerpc/nofpu/fenv_libc.h: New file.
diff -urN libc25-cvstip-20070104/soft-fp/op-4.h libc24/soft-fp/op-4.h
--- libc25-cvstip-20070104/soft-fp/op-4.h 2006-04-04 03:24:47.000000000 -0500
+++ libc24/soft-fp/op-4.h 2007-01-11 11:00:53.082820752 -0600
@@ -564,7 +564,7 @@
r1 = x1 - y1; \
_c2 = r1 > x1; \
r1 -= _c1; \
- _c2 |= r1 > _c1; \
+ _c2 |= _c1 && (y1 == x1); \
r2 = x2 - y2 - _c2; \
} while (0)
#endif
@@ -578,11 +578,11 @@
r1 = x1 - y1; \
_c2 = r1 > x1; \
r1 -= _c1; \
- _c2 |= r1 > _c1; \
+ _c2 |= _c1 && (y1 == x1); \
r2 = x2 - y2; \
_c3 = r2 > x2; \
r2 -= _c2; \
- _c3 |= r2 > _c2; \
+ _c3 |= _c2 && (y2 == x2); \
r3 = x3 - y3 - _c3; \
} while (0)
#endif
diff -urN libc25-cvstip-20070104/soft-fp/op-common.h libc24/soft-fp/op-common.h
--- libc25-cvstip-20070104/soft-fp/op-common.h 2006-04-04 03:24:47.000000000 -0500
+++ libc24/soft-fp/op-common.h 2007-01-11 17:17:17.301821864 -0600
@@ -99,10 +99,10 @@
else \
{ \
X##_e = _FP_EXPMAX_##fs - 1; \
- FP_SET_EXCEPTION(FP_EX_OVERFLOW); \
- FP_SET_EXCEPTION(FP_EX_INEXACT); \
_FP_FRAC_SET_##wc(X, _FP_MAXFRAC_##wc); \
} \
+ FP_SET_EXCEPTION(FP_EX_INEXACT); \
+ FP_SET_EXCEPTION(FP_EX_OVERFLOW); \
} while (0)
/* Check for a semi-raw value being a signaling NaN and raise the
@@ -131,10 +131,12 @@
/* Prepare to pack an fp value in semi-raw mode: the mantissa is
rounded and shifted right, with the rounding possibly increasing
- the exponent (including changing a finite value to infinity). */
+ the exponent (including changing a finite value to infinity).
+ Be sure not to round NaNs. */
#define _FP_PACK_SEMIRAW(fs, wc, X) \
do { \
- _FP_ROUND(wc, X); \
+ if(X##_e != _FP_EXPMAX_##fs) \
+ _FP_ROUND(wc, X); \
if (_FP_FRAC_HIGH_##fs(X) \
& (_FP_OVERFLOW_##fs >> 1)) \
{ \
diff -urN libc25-cvstip-20070104/sysdeps/powerpc/nofpu/fenv_libc.h libc24/sysdeps/powerpc/nofpu/fenv_libc.h
--- libc25-cvstip-20070104/sysdeps/powerpc/nofpu/fenv_libc.h Wed Dec 31 18:00:00 1969
+++ libc24/sysdeps/powerpc/nofpu/fenv_libc.h Thu Jan 11 11:00:53 2007
@@ -0,0 +1,29 @@
+/* Internal libc stuff for floating point environment routines.
+ Copyright (C) 2006 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _FENV_LIBC_H
+#define _FENV_LIBC_H 1
+
+/* fenv_libc.h is used in libm implementations of ldbl-128ibm. So we
+ need this version in the soft-fp to at minimum include fenv.h to
+ get the fegetround definition. */
+
+#include <fenv.h>
+
+#endif /* fenv_libc.h */