q_ulltoq.c

来自「glibc 库, 不仅可以学习使用库函数,还可以学习函数的具体实现,是提高功力的」· C语言 代码 · 共 39 行

/* Software floating-point emulation.
   Return (long double)a
   Copyright (C) 1997, 1999, 2000, 2006 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Richard Henderson ([e-mail]) and
		  Jakub Jelinek ([e-mail]).

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include "soft-fp.h"
#include "quad.h"

long double _q_ulltoq(const unsigned long long a)
{
  FP_DECL_EX;
  FP_DECL_Q(C);
  long double c;
  unsigned long long b = a;

  FP_FROM_INT_Q(C, b, 64, unsigned long long);
  FP_PACK_RAW_Q(c, C);
  FP_CLEAR_EXCEPTIONS;
  FP_HANDLE_EXCEPTIONS;
  return c;
}