yann@1: Taken from http://sources.redhat.com/ml/crossgcc/2004-02/msg00104.html yann@1: Author: addsub@eyou.com yann@1: Target: ARM yann@1: yann@1: Fixes http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/execute/920501-8.c yann@1: and makes printf("%f", 1.0) work. yann@1: yann@1: Lennert Buytenhek wrote in http://sources.redhat.com/ml/crossgcc/2004-09/msg00115.html : yann@1: It ... fixes the 'printf("%f\n", 0.5); prints 0.000000' and general 'floating point yann@1: is broken' on my big-endian hardfloat FPA ARM platform. ... yann@1: It's definitely needed for hardfloat. So I'd think it's needed for yann@1: big-endian systems in any case, and for VFP on little-endian systems yann@1: too. Someone would have to verify that though. yann@1: yann@1: Lennert Buytenhek wrote in http://sources.redhat.com/ml/crossgcc/2004-09/msg00123.html yann@1: I just had a look at glibc-20040830, and [this patch] is still needed and useful yann@1: for this version. glibc-20040830 out-of-the-box still contains the yann@1: following wrong assumptions: yann@1: - sysdeps/arm/bits/endian.h: float word order is big endian (which it is yann@1: not on vfp systems) yann@1: - sysdeps/arm/gmp-mparam.h: IEEE doubles are mixed endian (which they yann@1: are not on big endian systems, neither on vfp systems) yann@1: - sysdeps/arm/ieee754.h: IEEE doubles are in little endian byte order yann@1: (which they are not on big endian systems) yann@1: [This patch] seems the right solution for all of these issues. yann@1: yann@1: Dimitry Andric wrote in http://sources.redhat.com/ml/crossgcc/2004-09/msg00132.html : yann@1: It's even needed for glibc CVS, AFAICS. yann@1: The patch hunk which modifies glibc.new/sysdeps/arm/bits/endian.h yann@1: (currently at version 1.4) is only needed for proper VFP operation. yann@1: But the hunk which modifies sysdeps/arm/gmp-mparam.h, and the hunk yann@1: that deletes sysdeps/arm/ieee754.h (yes, this IS correct), are needed yann@1: for proper operation of *any* FP model on big endian ARM. yann@1: yann@1: See also discussion in followups to yann@1: http://sources.redhat.com/ml/crossgcc/2004-05/msg00245.html) yann@1: yann@1: Message-ID: <276985760.37584@eyou.com> yann@1: Received: from unknown (HELO eyou.com) (172.16.2.2) yann@1: by 0.0.0.0 with SMTP; Tue, 17 Feb 2004 10:42:40 +0800 yann@1: Received: (qmail 8238 invoked by uid 65534); 17 Feb 2004 10:42:38 +0800 yann@1: Date: 17 Feb 2004 10:42:38 +0800 yann@1: Message-ID: <20040217104238.8237.qmail@eyou.com> yann@1: From: "add" yann@1: To: dank@kegel.com yann@1: Reply-To: "add" yann@1: Subject: Re:   problem while building arm vfp softfloat gcc ` yann@1: yann@1: Hi, Dan, This is a patch I applied to my glibc-2.3.2, then my softfloat yann@1: toolchain can printf("%f\n",1.0). So you may have a try of this yann@1: yann@1: yann@1: diff -uNrp glibc.old/sysdeps/arm/bits/endian.h glibc.new/sysdeps/arm/bits/endian.h yann@1: --- glibc.old/sysdeps/arm/bits/endian.h 1999-04-12 11:59:13.000000000 -0400 yann@1: +++ glibc.new/sysdeps/arm/bits/endian.h 2004-02-12 09:15:13.000000000 -0500 yann@1: @@ -9,4 +9,9 @@ yann@1: #else yann@1: #define __BYTE_ORDER __LITTLE_ENDIAN yann@1: #endif yann@1: + yann@1: +#ifdef __VFP_FP__ yann@1: +#define __FLOAT_WORD_ORDER __BYTE_ORDER yann@1: +#else yann@1: #define __FLOAT_WORD_ORDER __BIG_ENDIAN yann@1: +#endif yann@1: diff -uNrp glibc.old/sysdeps/arm/gmp-mparam.h glibc.new/sysdeps/arm/gmp-mparam.h yann@1: --- glibc.old/sysdeps/arm/gmp-mparam.h 2001-07-07 15:21:19.000000000 -0400 yann@1: +++ glibc.new/sysdeps/arm/gmp-mparam.h 2004-02-12 09:15:13.000000000 -0500 yann@1: @@ -26,5 +26,13 @@ MA 02111-1307, USA. */ yann@1: #define BITS_PER_SHORTINT 16 yann@1: #define BITS_PER_CHAR 8 yann@1: yann@1: -#define IEEE_DOUBLE_BIG_ENDIAN 0 yann@1: -#define IEEE_DOUBLE_MIXED_ENDIAN 1 yann@1: +#if defined(__ARMEB__) yann@1: +# define IEEE_DOUBLE_MIXED_ENDIAN 0 yann@1: +# define IEEE_DOUBLE_BIG_ENDIAN 1 yann@1: +#elif defined(__VFP_FP__) yann@1: +# define IEEE_DOUBLE_MIXED_ENDIAN 0 yann@1: +# define IEEE_DOUBLE_BIG_ENDIAN 0 yann@1: +#else yann@1: +# define IEEE_DOUBLE_BIG_ENDIAN 0 yann@1: +# define IEEE_DOUBLE_MIXED_ENDIAN 1 yann@1: +#endif yann@1: diff -uNrp glibc.old/sysdeps/arm/ieee754.h glibc.new/sysdeps/arm/ieee754.h yann@1: --- glibc.old/sysdeps/arm/ieee754.h 2001-07-07 15:21:19.000000000 -0400 yann@1: +++ glibc.new/sysdeps/arm/ieee754.h 1969-12-31 19:00:00.000000000 -0500 yann@1: @@ -1,115 +0,0 @@ yann@1: -/* Copyright (C) 1992, 1995, 1996, 1998 Free Software Foundation, Inc. yann@1: - This file is part of the GNU C Library. yann@1: - yann@1: - The GNU C Library is free software; you can redistribute it and/or yann@1: - modify it under the terms of the GNU Lesser General Public yann@1: - License as published by the Free Software Foundation; either yann@1: - version 2.1 of the License, or (at your option) any later version. yann@1: - yann@1: - The GNU C Library is distributed in the hope that it will be useful, yann@1: - but WITHOUT ANY WARRANTY; without even the implied warranty of yann@1: - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yann@1: - Lesser General Public License for more details. yann@1: - yann@1: - You should have received a copy of the GNU Lesser General Public yann@1: - License along with the GNU C Library; if not, write to the Free yann@1: - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA yann@1: - 02111-1307 USA. */ yann@1: - yann@1: -#ifndef _IEEE754_H yann@1: - yann@1: -#define _IEEE754_H 1 yann@1: -#include yann@1: - yann@1: -#include yann@1: - yann@1: -__BEGIN_DECLS yann@1: - yann@1: -union ieee754_float yann@1: - { yann@1: - float f; yann@1: - yann@1: - /* This is the IEEE 754 single-precision format. */ yann@1: - struct yann@1: - { yann@1: - unsigned int mantissa:23; yann@1: - unsigned int exponent:8; yann@1: - unsigned int negative:1; yann@1: - } ieee; yann@1: - yann@1: - /* This format makes it easier to see if a NaN is a signalling NaN. */ yann@1: - struct yann@1: - { yann@1: - unsigned int mantissa:22; yann@1: - unsigned int quiet_nan:1; yann@1: - unsigned int exponent:8; yann@1: - unsigned int negative:1; yann@1: - } ieee_nan; yann@1: - }; yann@1: - yann@1: -#define IEEE754_FLOAT_BIAS 0x7f /* Added to exponent. */ yann@1: - yann@1: - yann@1: -union ieee754_double yann@1: - { yann@1: - double d; yann@1: - yann@1: - /* This is the IEEE 754 double-precision format. */ yann@1: - struct yann@1: - { yann@1: - unsigned int mantissa0:20; yann@1: - unsigned int exponent:11; yann@1: - unsigned int negative:1; yann@1: - unsigned int mantissa1:32; yann@1: - } ieee; yann@1: - yann@1: - /* This format makes it easier to see if a NaN is a signalling NaN. */ yann@1: - struct yann@1: - { yann@1: - unsigned int mantissa0:19; yann@1: - unsigned int quiet_nan:1; yann@1: - unsigned int exponent:11; yann@1: - unsigned int negative:1; yann@1: - unsigned int mantissa1:32; yann@1: - } ieee_nan; yann@1: - }; yann@1: - yann@1: -#define IEEE754_DOUBLE_BIAS 0x3ff /* Added to exponent. */ yann@1: - yann@1: - yann@1: -/* The following two structures are correct for `new' floating point systems but yann@1: - wrong for the old FPPC. The only solution seems to be to avoid their use on yann@1: - old hardware. */ yann@1: - yann@1: -union ieee854_long_double yann@1: - { yann@1: - long double d; yann@1: - yann@1: - /* This is the IEEE 854 double-extended-precision format. */ yann@1: - struct yann@1: - { yann@1: - unsigned int exponent:15; yann@1: - unsigned int empty:16; yann@1: - unsigned int negative:1; yann@1: - unsigned int mantissa1:32; yann@1: - unsigned int mantissa0:32; yann@1: - } ieee; yann@1: - yann@1: - /* This is for NaNs in the IEEE 854 double-extended-precision format. */ yann@1: - struct yann@1: - { yann@1: - unsigned int exponent:15; yann@1: - unsigned int empty:16; yann@1: - unsigned int negative:1; yann@1: - unsigned int mantissa1:32; yann@1: - unsigned int mantissa0:30; yann@1: - unsigned int quiet_nan:1; yann@1: - unsigned int one:1; yann@1: - } ieee_nan; yann@1: - }; yann@1: - yann@1: -#define IEEE854_LONG_DOUBLE_BIAS 0x3fff yann@1: - yann@1: -__END_DECLS yann@1: - yann@1: -#endif /* ieee754.h */