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Hi! Ping. On Thu, 23 May 2013 18:00:10 +0200, Thomas Schwinge <thomas@codesourcery.com> wrote: > BZ #15522: > | strtod ("nan(N)") (and likewise for the other float types) exhibits wrong > | behavior such that for architectures defining > | HIGH_ORDER_BIT_IS_SET_FOR_SNAN, a sNaN is returned for N = 0, and for > | other architectures a sNaN is returned for positive integral N != 0. > > Use the ieee754_* unions' ieee_nan member for easily setting a NaN's > mantissa without touching the quiet/signaling bit (or anything else), and > only if that new mantissa is unequal to zero (denoting infinity) use it > to overwrite the generic NaN's mantissa (which has been pre-set before > invoking SET_MANTISSA). > > Tested for several MIPS multilibs, x86, x86_64, PowerPC -m64 (but a > PowerPC maintainer please confirm the > sysdeps/ieee754/ldbl-128ibm/ieee754.h change; I copied the ieee member > and changed it as done for other ldbl-*/ieee754.h's long double > structures/unions). > > * stdlib/strtof_l.c (SET_MANTISSA): Rewrite. > * stdlib/strtod_l.c (SET_MANTISSA): Likewise. > * sysdeps/ieee754/ldbl-64-128/strtold_l.c (SET_MANTISSA): Likewise. > * sysdeps/ieee754/ldbl-96/strtold_l.c (SET_MANTISSA): Likewise. > * sysdeps/ieee754/ldbl-128/strtold_l.c (SET_MANTISSA): Likewise. > * sysdeps/ieee754/ldbl-128ibm/strtold_l.c (SET_MANTISSA): Likewise. > * sysdeps/ieee754/ldbl-128ibm/ieee754.h (ibm_extended_long_double): > Add ieee_nan member. > * stdlib/tst-strtod6.c (test): New function, renamed from do_test. > (do_test): New function. > > diff --git stdlib/strtod_l.c stdlib/strtod_l.c > index 47247b5..5ed5a35 100644 > --- stdlib/strtod_l.c > +++ stdlib/strtod_l.c > @@ -42,11 +42,10 @@ extern unsigned long long int ____strtoull_l_internal (const char *, char **, > # define SET_MANTISSA(flt, mant) \ > do { union ieee754_double u; \ > u.d = (flt); \ > - if ((mant & 0xfffffffffffffULL) == 0) \ > - mant = 0x8000000000000ULL; \ > - u.ieee.mantissa0 = ((mant) >> 32) & 0xfffff; \ > - u.ieee.mantissa1 = (mant) & 0xffffffff; \ > - (flt) = u.d; \ > + u.ieee_nan.mantissa0 = (mant) >> 32; \ > + u.ieee_nan.mantissa1 = (mant); \ > + if ((u.ieee.mantissa0 | u.ieee.mantissa1) != 0) \ > + (flt) = u.d; \ > } while (0) > #endif > /* End of configuration part. */ > diff --git stdlib/strtof_l.c stdlib/strtof_l.c > index 6fb44bd..c4c1c1f 100644 > --- stdlib/strtof_l.c > +++ stdlib/strtof_l.c > @@ -37,10 +37,9 @@ extern unsigned long long int ____strtoull_l_internal (const char *, char **, > #define SET_MANTISSA(flt, mant) \ > do { union ieee754_float u; \ > u.f = (flt); \ > - if ((mant & 0x7fffff) == 0) \ > - mant = 0x400000; \ > - u.ieee.mantissa = (mant) & 0x7fffff; \ > - (flt) = u.f; \ > + u.ieee_nan.mantissa = (mant); \ > + if (u.ieee.mantissa != 0) \ > + (flt) = u.f; \ > } while (0) > > #include "strtod_l.c" > diff --git stdlib/tst-strtod6.c stdlib/tst-strtod6.c > index 1d87266..15e79fd 100644 > --- stdlib/tst-strtod6.c > +++ stdlib/tst-strtod6.c > @@ -4,12 +4,13 @@ > #include <string.h> > > static int > -do_test (void) > +test (const char str[]) > { > - static const char str[] = "NaN(blabla)something"; > char *endp; > int result = 0; > > + puts (str); > + > double d = strtod (str, &endp); > if (!isnan (d)) > { > @@ -64,5 +65,24 @@ do_test (void) > return result; > } > > +static int > +do_test (void) > +{ > + int result = 0; > + > + result |= test ("NaN(blabla)something"); > + result |= test ("NaN(1234)something"); > + /* UINT32_MAX. */ > + result |= test ("NaN(4294967295)something"); > + /* UINT64_MAX. */ > + result |= test ("NaN(18446744073709551615)something"); > + /* The case of zero is special in that "something" has to be done to make the > + mantissa different from zero, which would mean infinity instead of > + NaN. */ > + result |= test ("NaN(0)something"); > + > + return result; > +} > + > #define TEST_FUNCTION do_test () > #include "../test-skeleton.c" > diff --git sysdeps/ieee754/ldbl-128/strtold_l.c sysdeps/ieee754/ldbl-128/strtold_l.c > index 8e0bc03..d3a1d1e 100644 > --- sysdeps/ieee754/ldbl-128/strtold_l.c > +++ sysdeps/ieee754/ldbl-128/strtold_l.c > @@ -34,11 +34,13 @@ > #define SET_MANTISSA(flt, mant) \ > do { union ieee854_long_double u; \ > u.d = (flt); \ > - u.ieee.mantissa0 = 0x8000; \ > - u.ieee.mantissa1 = 0; \ > - u.ieee.mantissa2 = ((mant) >> 32); \ > - u.ieee.mantissa3 = (mant) & 0xffffffff; \ > - (flt) = u.d; \ > + u.ieee_nan.mantissa0 = 0; \ > + u.ieee_nan.mantissa1 = 0; \ > + u.ieee_nan.mantissa2 = (mant) >> 32; \ > + u.ieee_nan.mantissa3 = (mant); \ > + if ((u.ieee.mantissa0 | u.ieee.mantissa1 \ > + | u.ieee.mantissa2 | u.ieee.mantissa3) != 0) \ > + (flt) = u.d; \ > } while (0) > > #include <strtod_l.c> > diff --git sysdeps/ieee754/ldbl-128ibm/ieee754.h sysdeps/ieee754/ldbl-128ibm/ieee754.h > index e5644f5..9e94f53 100644 > --- sysdeps/ieee754/ldbl-128ibm/ieee754.h > +++ sysdeps/ieee754/ldbl-128ibm/ieee754.h > @@ -199,6 +199,25 @@ union ibm_extended_long_double > unsigned int mantissa2:20; > unsigned int mantissa3:32; > } ieee; > + > + /* This format makes it easier to see if a NaN is a signalling NaN. */ > + struct > + { /* Big endian. There is no other. */ > + > + unsigned int negative:1; > + unsigned int exponent:11; > + unsigned int quiet_nan:1; > + /* Together Mantissa0-3 comprise the mantissa. */ > + unsigned int mantissa0:19; > + unsigned int mantissa1:32; > + > + unsigned int negative2:1; > + unsigned int exponent2:11; > + /* There is an implied 1 here? */ > + /* Together these comprise the mantissa. */ > + unsigned int mantissa2:20; > + unsigned int mantissa3:32; > + } ieee_nan; > }; > > #define IBM_EXTENDED_LONG_DOUBLE_BIAS 0x3ff /* Added to exponent. */ > diff --git sysdeps/ieee754/ldbl-128ibm/strtold_l.c sysdeps/ieee754/ldbl-128ibm/strtold_l.c > index 93415f0..04e3288 100644 > --- sysdeps/ieee754/ldbl-128ibm/strtold_l.c > +++ sysdeps/ieee754/ldbl-128ibm/strtold_l.c > @@ -44,11 +44,10 @@ libc_hidden_proto (STRTOF) > # define SET_MANTISSA(flt, mant) \ > do { union ibm_extended_long_double u; \ > u.d = (flt); \ > - if ((mant & 0xfffffffffffffULL) == 0) \ > - mant = 0x8000000000000ULL; \ > - u.ieee.mantissa0 = ((mant) >> 32) & 0xfffff; \ > - u.ieee.mantissa1 = (mant) & 0xffffffff; \ > - (flt) = u.d; \ > + u.ieee_nan.mantissa0 = (mant) >> 32; \ > + u.ieee_nan.mantissa1 = (mant); \ > + if ((u.ieee.mantissa0 | u.ieee.mantissa1) != 0) \ > + (flt) = u.d; \ > } while (0) > > #include <strtod_l.c> > diff --git sysdeps/ieee754/ldbl-64-128/strtold_l.c sysdeps/ieee754/ldbl-64-128/strtold_l.c > index 8182b2b..e9b33f2 100644 > --- sysdeps/ieee754/ldbl-64-128/strtold_l.c > +++ sysdeps/ieee754/ldbl-64-128/strtold_l.c > @@ -44,11 +44,13 @@ libc_hidden_proto (STRTOF) > #define SET_MANTISSA(flt, mant) \ > do { union ieee854_long_double u; \ > u.d = (flt); \ > - u.ieee.mantissa0 = 0x8000; \ > - u.ieee.mantissa1 = 0; \ > - u.ieee.mantissa2 = ((mant) >> 32); \ > - u.ieee.mantissa3 = (mant) & 0xffffffff; \ > - (flt) = u.d; \ > + u.ieee_nan.mantissa0 = 0; \ > + u.ieee_nan.mantissa1 = 0; \ > + u.ieee_nan.mantissa2 = (mant) >> 32; \ > + u.ieee_nan.mantissa3 = (mant); \ > + if ((u.ieee.mantissa0 | u.ieee.mantissa1 \ > + | u.ieee.mantissa2 | u.ieee.mantissa3) != 0) \ > + (flt) = u.d; \ > } while (0) > > #include <strtod_l.c> > diff --git sysdeps/ieee754/ldbl-96/strtold_l.c sysdeps/ieee754/ldbl-96/strtold_l.c > index ded84f3..dccf98c 100644 > --- sysdeps/ieee754/ldbl-96/strtold_l.c > +++ sysdeps/ieee754/ldbl-96/strtold_l.c > @@ -34,11 +34,10 @@ > #define SET_MANTISSA(flt, mant) \ > do { union ieee854_long_double u; \ > u.d = (flt); \ > - if ((mant & 0x7fffffffffffffffULL) == 0) \ > - mant = 0x4000000000000000ULL; \ > - u.ieee.mantissa0 = (((mant) >> 32) & 0x7fffffff) | 0x80000000; \ > - u.ieee.mantissa1 = (mant) & 0xffffffff; \ > - (flt) = u.d; \ > + u.ieee_nan.mantissa0 = (mant) >> 32; \ > + u.ieee_nan.mantissa1 = (mant); \ > + if ((u.ieee.mantissa0 | u.ieee.mantissa1) != 0) \ > + (flt) = u.d; \ > } while (0) > > #include <stdlib/strtod_l.c> > > > I used the following hack for manually verifying the expected bit > patterns for the resulting NaNs' mantissas; not proposing to commit. ;-) > > diff --git stdlib/tst-strtod6.c stdlib/tst-strtod6.c > index 15e79fd..05532b6 100644 > --- stdlib/tst-strtod6.c > +++ stdlib/tst-strtod6.c > @@ -2,6 +2,7 @@ > #include <stdio.h> > #include <stdlib.h> > #include <string.h> > +#include <stdint.h> > > static int > test (const char str[]) > @@ -12,6 +13,9 @@ test (const char str[]) > puts (str); > > double d = strtod (str, &endp); > + printf("%08x ", ((uint32_t *) &d)[0]); > + printf("%08x ", ((uint32_t *) &d)[1]); > + puts(""); > if (!isnan (d)) > { > puts ("strtod did not return NAN"); > @@ -29,6 +33,8 @@ test (const char str[]) > } > > float f = strtof (str, &endp); > + printf("%08x ", ((uint32_t *) &f)[0]); > + puts(""); > if (!isnanf (f)) > { > puts ("strtof did not return NAN"); > @@ -46,6 +52,11 @@ test (const char str[]) > } > > long double ld = strtold (str, &endp); > + printf("%08x ", ((uint32_t *) &ld)[0]); > + printf("%08x ", ((uint32_t *) &ld)[1]); > + printf("%08x ", ((uint32_t *) &ld)[2]); > + printf("%08x ", ((uint32_t *) &ld)[3]); > + puts(""); > if (!isnan (ld)) > { > puts ("strtold did not return NAN"); GrÃÃe, Thomas
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