Copyright 1999, 2001-2017 Free Software Foundation, Inc.

Contributed by the AriC and Caramba projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR 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 3 of the License, or (at your

option) any later version.

The GNU MPFR 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 MPFR Library; see the file COPYING.LESSER.  If not, see

http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,

51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

##############################################################################

Known bugs:

* The overflow/underflow exceptions may be badly handled in some functions;

  specially when the intermediary internal results have exponent which

  exceeds the hardware limit (2^30 for a 32 bits CPU, and 2^62 for a 64 bits

  CPU) or the exact result is close to an overflow/underflow threshold.

* Under Linux/x86 with the traditional FPU, some functions do not work

  if the FPU rounding precision has been changed to single (this is a

  bad practice and should be useless, but one never knows what other

  software will do).

* Some functions do not use MPFR_SAVE_EXPO_* macros, thus do not behave

  correctly in a reduced exponent range.

* Function hypot gives incorrect result when on the one hand the difference

  between parameters' exponents is near 2*MPFR_EMAX_MAX and on the other hand

  the output precision or the precision of the parameter with greatest

  absolute value is greater than 2*MPFR_EMAX_MAX-4.

Potential bugs:

* Possible incorrect results due to internal underflow, which can lead to

  a huge loss of accuracy while the error analysis doesn't take that into

  account. If the underflow occurs at the last function call (just before

  the MPFR_CAN_ROUND), the result should be correct (or MPFR gets into an

  infinite loop). TODO: check the code and the error analysis.

* Possible integer overflows on some machines.

* Possible bugs with huge precisions (> 2^30).

* Possible bugs if the chosen exponent range does not allow to represent

  the range [1/16, 16].

* Possible infinite loop in some functions for particular cases: when

  the exact result is an exactly representable number or the middle of

  consecutive two such numbers. However for non-algebraic functions, it is

  believed that no such case exists, except the well-known cases like cos(0)=1,

  exp(0)=1, and so on, and the x^y function when y is an integer or y=1/2^k.

* The mpfr_set_ld function may be quite slow if the long double type has an

  exponent of more than 15 bits.

* mpfr_set_d may give wrong results on some non-IEEE architectures.

* Error analysis for some functions may be incorrect (out-of-date due

  to modifications in the code?).

* Possible use of non-portable feature (pre-C99) of the integer division

  with negative result.