From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3118 invoked by alias); 5 Jun 2007 15:40:06 -0000 Received: (qmail 3102 invoked by uid 22791); 5 Jun 2007 15:40:05 -0000 X-Spam-Check-By: sourceware.org Received: from sunsite.ms.mff.cuni.cz (HELO sunsite.mff.cuni.cz) (195.113.15.26) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 05 Jun 2007 15:40:00 +0000 Received: from sunsite.mff.cuni.cz (localhost.localdomain [127.0.0.1]) by sunsite.mff.cuni.cz (8.13.8/8.13.8) with ESMTP id l55Fgfpl020533; Tue, 5 Jun 2007 17:42:41 +0200 Received: (from jakub@localhost) by sunsite.mff.cuni.cz (8.13.8/8.13.8/Submit) id l55Fgdm7020498; Tue, 5 Jun 2007 17:42:39 +0200 Date: Tue, 05 Jun 2007 15:40:00 -0000 From: Jakub Jelinek To: Ulrich Drepper , Steven Munroe Cc: Glibc hackers Subject: [PATCH] Fix strtold with IBM long double Message-ID: <20070605154238.GN3081@sunsite.mff.cuni.cz> Reply-To: Jakub Jelinek Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.2i Mailing-List: contact libc-hacker-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-hacker-owner@sourceware.org X-SW-Source: 2007-06/txt/msg00003.txt.bz2 Hi! As the adjusted tst-sprintf2 testcase shows there were a bunch of bugs in strtold/*scanf %La on ppc{,64}. 2007-06-05 Jakub Jelinek * sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c (__mpn_construct_long_double): Fix conversion where result ought to be smaller than __LDBL_MIN__, or the low double should be denormal. Fix decision where to negate low double - honor round to even rules. * stdio-common/tst-sprintf2.c: Include string.h. (COMPARE_LDBL): Define. (TEST): Also test whether a string hexadecimal float representation can be parsed back to the number. (main): Add a couple of further tests. --- libc/sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c.jj 2006-01-28 01:07:25.000000000 +0100 +++ libc/sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c 2007-06-05 15:37:15.000000000 +0200 @@ -1,4 +1,4 @@ -/* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2002, 2003, 2004, 2006 +/* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2002, 2003, 2004, 2006, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -31,19 +31,20 @@ long double __mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign) { union ibm_extended_long_double u; - unsigned long hidden2, lzcount; + unsigned long lzcount; unsigned long long hi, lo; + int exponent2; u.ieee.negative = sign; u.ieee.negative2 = sign; u.ieee.exponent = expt + IBM_EXTENDED_LONG_DOUBLE_BIAS; - u.ieee.exponent2 = expt - 53 + IBM_EXTENDED_LONG_DOUBLE_BIAS; + u.ieee.exponent2 = 0; + exponent2 = expt - 53 + IBM_EXTENDED_LONG_DOUBLE_BIAS; #if BITS_PER_MP_LIMB == 32 /* The low order 53 bits (52 + hidden) go into the lower double */ lo = frac_ptr[0]; lo |= (frac_ptr[1] & ((1LL << (53 - 32)) - 1)) << 32; - hidden2 = (frac_ptr[1] >> (52 - 32)) & ((mp_limb_t) 1); /* The high order 53 bits (52 + hidden) go into the upper double */ hi = (frac_ptr[1] >> (53 - 32)) & ((1 << 11) - 1); hi |= ((unsigned long long) frac_ptr[2]) << 11; @@ -51,7 +52,6 @@ __mpn_construct_long_double (mp_srcptr f #elif BITS_PER_MP_LIMB == 64 /* The low order 53 bits (52 + hidden) go into the lower double */ lo = frac_ptr[0] & (((mp_limb_t) 1 << 53) - 1); - hidden2 = (frac_ptr[0] >> 52) & ((mp_limb_t) 1); /* The high order 53 bits (52 + hidden) go into the upper double */ hi = (frac_ptr[0] >> 53) & (((mp_limb_t) 1 << 11) - 1); hi |= (frac_ptr[1] << 11); @@ -59,14 +59,62 @@ __mpn_construct_long_double (mp_srcptr f #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for" #endif + if ((hi & (1LL << 52)) == 0 && (hi | lo) != 0) + { + /* denormal number */ + unsigned long long val = hi ? hi : lo; + + if (sizeof (val) == sizeof (long)) + lzcount = __builtin_clzl (val); + else if ((val >> 32) != 0) + lzcount = __builtin_clzl ((long) (val >> 32)); + else + lzcount = __builtin_clzl ((long) val) + 32; + if (hi) + lzcount = lzcount - 11; + else + lzcount = lzcount + 42; + + if (lzcount > u.ieee.exponent) + { + lzcount = u.ieee.exponent; + u.ieee.exponent = 0; + exponent2 -= lzcount; + } + else + { + u.ieee.exponent -= (lzcount - 1); + exponent2 -= (lzcount - 1); + } + + if (lzcount <= 53) + { + hi = (hi << lzcount) | (lo >> (53 - lzcount)); + lo = (lo << lzcount) & ((1LL << 53) - 1); + } + else + { + hi = lo << (lzcount - 53); + lo = 0; + } + } + if (lo != 0L) { /* hidden2 bit of low double controls rounding of the high double. - If hidden2 is '1' then round up hi and adjust lo (2nd mantissa) + If hidden2 is '1' and either the explicit mantissa is non-zero + or hi is odd, then round up hi and adjust lo (2nd mantissa) plus change the sign of the low double to compensate. */ - if (hidden2) + if ((lo & (1LL << 52)) != 0 + && ((hi & 1) != 0 || (lo & ((1LL << 52) - 1)))) { hi++; + if ((hi & ((1LL << 52) - 1)) == 0) + { + if ((hi & (1LL << 53)) != 0) + hi -= 1LL << 52; + u.ieee.exponent++; + } u.ieee.negative2 = !sign; lo = (1LL << 53) - lo; } @@ -85,17 +133,18 @@ __mpn_construct_long_double (mp_srcptr f if (lzcount > 0) { lo = lo << lzcount; - u.ieee.exponent2 = u.ieee.exponent2 - lzcount; + exponent2 = exponent2 - lzcount; } + if (exponent2 > 0) + u.ieee.exponent2 = exponent2; + else + lo >>= 1 - exponent2; } else - { - u.ieee.negative2 = 0; - u.ieee.exponent2 = 0; - } + u.ieee.negative2 = 0; u.ieee.mantissa3 = lo & 0xffffffffLL; - u.ieee.mantissa2 = (lo >> 32) & 0xffffff; + u.ieee.mantissa2 = (lo >> 32) & 0xfffff; u.ieee.mantissa1 = hi & 0xffffffffLL; u.ieee.mantissa0 = (hi >> 32) & ((1LL << (LDBL_MANT_DIG - 86)) - 1); --- libc/stdio-common/tst-sprintf2.c.jj 2007-06-04 14:04:35.000000000 +0200 +++ libc/stdio-common/tst-sprintf2.c 2007-06-05 15:56:55.000000000 +0200 @@ -1,14 +1,22 @@ #include #include #include +#include int main (void) { - volatile union { long double l; long long x[2]; } u; + volatile union { long double l; long long x[2]; } u, v; char buf[64]; int result = 0; +#if LDBL_MANT_DIG == 106 || LDBL_MANT_DIG == 113 +# define COMPARE_LDBL(u, v) \ + ((u).l == (v).l && (u).x[0] == (v).x[0] && (u).x[1] == (v).x[1]) +#else +# define COMPARE_LDBL(u, v) ((u).l == (v).l) +#endif + #define TEST(val) \ do \ { \ @@ -19,6 +27,12 @@ main (void) printf ("Error on line %d: %s != %s\n", __LINE__, buf, #val); \ result = 1; \ } \ + if (sscanf (#val, "%La", &v.l) != 1 || !COMPARE_LDBL (u, v)) \ + { \ + printf ("Error sscanf on line %d: %La != %La\n", __LINE__, \ + u.l, v.l); \ + result = 1; \ + } \ /* printf ("%s %La %016Lx %016Lx\n", #val, u.l, u.x[0], u.x[1]); */ \ } \ while (0) @@ -54,6 +68,15 @@ main (void) TEST (0x1.23456789abcdef123456789abc8p+64L); TEST (0x1.23456789abcde7123456789abc8p+64L); TEST (0x1.123456789abcdef123456789p-969L); +# if LDBL_MANT_DIG == 106 + TEST (-0x1.2d71957cc1263bbbeb1d365f1e8p-969L); + TEST (0x1.23456789abcdef0123456789abp-970L); + TEST (0x1.579bde02468acp-1001L); + TEST (0x0.abcdef0123456p-1022L); + TEST (0x1.abcdef0123456p-1022L); + TEST (0x1.abcdef012345678p-1014L); + TEST (0x1.abcdef0123456f8p-1014L); +# endif #endif return result; } Jakub