| Message ID | 20201224024554.3579622-2-siddhesh@sourceware.org |
|---|---|
| State | New |
| Headers | show |
| Series | x86 pseudo-normal numbers | expand |
On 23/12/2020 23:45, Siddhesh Poyarekar wrote: > Add support to treat pseudo-numbers specially and implement x86 > version to consider all of them as signaling. Ok with the above changes. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > sysdeps/generic/nan-pseudo-number.h | 32 ++++++++++++++++++++++++ > sysdeps/ieee754/ldbl-96/s_issignalingl.c | 11 +++++--- > sysdeps/x86/fpu/nan-pseudo-number.h | 30 ++++++++++++++++++++++ > 3 files changed, 70 insertions(+), 3 deletions(-) > create mode 100644 sysdeps/generic/nan-pseudo-number.h > create mode 100644 sysdeps/x86/fpu/nan-pseudo-number.h > > diff --git a/sysdeps/generic/nan-pseudo-number.h b/sysdeps/generic/nan-pseudo-number.h > new file mode 100644 > index 0000000000..1562e06e4b > --- /dev/null > +++ b/sysdeps/generic/nan-pseudo-number.h > @@ -0,0 +1,32 @@ > +/* Pseudo-normal number handling. Generic version. > + Copyright (C) 2020 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, see > + <https://www.gnu.org/licenses/>. */ > + > +#ifndef NAN_PSEUDO_NUMBER_H > +#define NAN_PSEUDO_NUMBER_H 1 > + > +/* Set this macro and override the definition of IS_PSEUDO_SIGNALING if pseudo > + numbers need special handling. */ > +#define HANDLE_PSEUDO_NUMBERS 0 > +static inline int > +is_pseudo_signaling (uint32_t exi __attribute__ ((unused)), > + uint32_t hxi __attribute__ ((unused))) > +{ > + return 0; > +} > + > +#endif /* nan-pseudo-number.h */ Afaik, there is no need to __attribute__ ((unused)) on arguments for static inline functions. > diff --git a/sysdeps/ieee754/ldbl-96/s_issignalingl.c b/sysdeps/ieee754/ldbl-96/s_issignalingl.c > index ec542ad468..37e05aa259 100644 > --- a/sysdeps/ieee754/ldbl-96/s_issignalingl.c > +++ b/sysdeps/ieee754/ldbl-96/s_issignalingl.c > @@ -19,12 +19,19 @@ > #include <math.h> > #include <math_private.h> > #include <nan-high-order-bit.h> > +#include <nan-pseudo-number.h> > > int > __issignalingl (long double x) > { > uint32_t exi, hxi, lxi; > GET_LDOUBLE_WORDS (exi, hxi, lxi, x); > + > + /* By default we do not recognize a pseudo NaN as sNaN. However on 80387 and > + later all pseudo numbers including pseudo NaNs result in a signal and are > + hence recognized as signaling. */ > + int ret = is_pseudo_signaling (exi, hxi); > + > #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN > # error not implemented > #else > @@ -34,11 +41,9 @@ __issignalingl (long double x) > hxi ^= 0x40000000; > /* If lxi != 0, then set any suitable bit of the significand in hxi. */ > hxi |= (lxi | -lxi) >> 31; > - /* We do not recognize a pseudo NaN as sNaN; they're invalid on 80387 and > - later. */ > /* We have to compare for greater (instead of greater or equal), because x's > significand being all-zero designates infinity not NaN. */ > - return ((exi & 0x7fff) == 0x7fff) && (hxi > 0xc0000000); > + return ret || (((exi & 0x7fff) == 0x7fff) && (hxi > 0xc0000000)); > #endif > } > libm_hidden_def (__issignalingl) Ok. > diff --git a/sysdeps/x86/fpu/nan-pseudo-number.h b/sysdeps/x86/fpu/nan-pseudo-number.h > new file mode 100644 > index 0000000000..ea43b175a1 > --- /dev/null > +++ b/sysdeps/x86/fpu/nan-pseudo-number.h > @@ -0,0 +1,30 @@ > +/* Pseudo-normal number handling. x86 version. > + Copyright (C) 2020 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, see > + <https://www.gnu.org/licenses/>. */ > + > +#ifndef NAN_PSEUDO_NUMBER_H > +#define NAN_PSEUDO_NUMBER_H 1 > + > +#define HANDLE_PSEUDO_NUMBERS 1 > +/* Pseudo numbers on x86 are always signaling. */ > +static inline int > +is_pseudo_signaling (uint32_t exi, uint32_t hxi) > +{ > + return ((exi & 0x7fff) && ((hxi & 0x80000000) == 0)); > +} > + > +#endif /* nan-pseudo-number.h */ > Ok.
On Thu, 24 Dec 2020, Siddhesh Poyarekar via Libc-alpha wrote:
> diff --git a/sysdeps/generic/nan-pseudo-number.h b/sysdeps/generic/nan-pseudo-number.h
I don't think this belongs in sysdeps/generic/. The "pseudo-number"
concept is specific to the ldbl-96 format; a "generic" header is really
something specific to ldbl-96 and so should go in sysdeps/ieee754/ldbl-96/
instead. (x86 and m68k have different rules regarding what encodings are
valid. ia64 manuals seem to suggest that only a subset of the encodings
that are invalid on x86 are also invalid on ia64 but I don't have access
to hardware to test.)
On Dez 31 2020, Joseph Myers wrote: > On Thu, 24 Dec 2020, Siddhesh Poyarekar via Libc-alpha wrote: > >> diff --git a/sysdeps/generic/nan-pseudo-number.h b/sysdeps/generic/nan-pseudo-number.h > > I don't think this belongs in sysdeps/generic/. The "pseudo-number" > concept is specific to the ldbl-96 format; a "generic" header is really > something specific to ldbl-96 and so should go in sysdeps/ieee754/ldbl-96/ > instead. (x86 and m68k have different rules regarding what encodings are > valid. m68k doesn't have the concept of pseudo-nan and pseudo-inf, as it treats the explicit integer bit in those formats as don't-care. Andreas.
diff --git a/sysdeps/generic/nan-pseudo-number.h b/sysdeps/generic/nan-pseudo-number.h new file mode 100644 index 0000000000..1562e06e4b --- /dev/null +++ b/sysdeps/generic/nan-pseudo-number.h @@ -0,0 +1,32 @@ +/* Pseudo-normal number handling. Generic version. + Copyright (C) 2020 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, see + <https://www.gnu.org/licenses/>. */ + +#ifndef NAN_PSEUDO_NUMBER_H +#define NAN_PSEUDO_NUMBER_H 1 + +/* Set this macro and override the definition of IS_PSEUDO_SIGNALING if pseudo + numbers need special handling. */ +#define HANDLE_PSEUDO_NUMBERS 0 +static inline int +is_pseudo_signaling (uint32_t exi __attribute__ ((unused)), + uint32_t hxi __attribute__ ((unused))) +{ + return 0; +} + +#endif /* nan-pseudo-number.h */ diff --git a/sysdeps/ieee754/ldbl-96/s_issignalingl.c b/sysdeps/ieee754/ldbl-96/s_issignalingl.c index ec542ad468..37e05aa259 100644 --- a/sysdeps/ieee754/ldbl-96/s_issignalingl.c +++ b/sysdeps/ieee754/ldbl-96/s_issignalingl.c @@ -19,12 +19,19 @@ #include <math.h> #include <math_private.h> #include <nan-high-order-bit.h> +#include <nan-pseudo-number.h> int __issignalingl (long double x) { uint32_t exi, hxi, lxi; GET_LDOUBLE_WORDS (exi, hxi, lxi, x); + + /* By default we do not recognize a pseudo NaN as sNaN. However on 80387 and + later all pseudo numbers including pseudo NaNs result in a signal and are + hence recognized as signaling. */ + int ret = is_pseudo_signaling (exi, hxi); + #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN # error not implemented #else @@ -34,11 +41,9 @@ __issignalingl (long double x) hxi ^= 0x40000000; /* If lxi != 0, then set any suitable bit of the significand in hxi. */ hxi |= (lxi | -lxi) >> 31; - /* We do not recognize a pseudo NaN as sNaN; they're invalid on 80387 and - later. */ /* We have to compare for greater (instead of greater or equal), because x's significand being all-zero designates infinity not NaN. */ - return ((exi & 0x7fff) == 0x7fff) && (hxi > 0xc0000000); + return ret || (((exi & 0x7fff) == 0x7fff) && (hxi > 0xc0000000)); #endif } libm_hidden_def (__issignalingl) diff --git a/sysdeps/x86/fpu/nan-pseudo-number.h b/sysdeps/x86/fpu/nan-pseudo-number.h new file mode 100644 index 0000000000..ea43b175a1 --- /dev/null +++ b/sysdeps/x86/fpu/nan-pseudo-number.h @@ -0,0 +1,30 @@ +/* Pseudo-normal number handling. x86 version. + Copyright (C) 2020 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, see + <https://www.gnu.org/licenses/>. */ + +#ifndef NAN_PSEUDO_NUMBER_H +#define NAN_PSEUDO_NUMBER_H 1 + +#define HANDLE_PSEUDO_NUMBERS 1 +/* Pseudo numbers on x86 are always signaling. */ +static inline int +is_pseudo_signaling (uint32_t exi, uint32_t hxi) +{ + return ((exi & 0x7fff) && ((hxi & 0x80000000) == 0)); +} + +#endif /* nan-pseudo-number.h */