binutils-gdb/gas/flonum-copy.c

/* flonum_copy.c - copy a flonum
   Copyright (C) 1987-2017 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   GAS 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, USA.  */

#include "as.h"

void
flonum_copy (FLONUM_TYPE *in, FLONUM_TYPE *out)
{
  unsigned int in_length;	/* 0 origin */
  unsigned int out_length;	/* 0 origin */

  out->sign = in->sign;
  in_length = in->leader - in->low;

  if (in->leader < in->low)
    {
      out->leader = out->low - 1;	/* 0.0 case */
    }
  else
    {
      out_length = out->high - out->low;
      /* Assume no GAPS in packing of littlenums.
	 I.e. sizeof(array) == sizeof(element) * number_of_elements.  */
      if (in_length <= out_length)
	{
	  {
	    /* For defensive programming, zero any high-order
	       littlenums we don't need.  This is destroying evidence
	       and wasting time, so why bother???  */
	    if (in_length < out_length)
	      {
		memset ((char *) (out->low + in_length + 1), '\0',
			out_length - in_length);
	      }
	  }
	  memcpy ((void *) (out->low), (void *) (in->low),
		  ((in_length + 1) * sizeof (LITTLENUM_TYPE)));
	  out->exponent = in->exponent;
	  out->leader = in->leader - in->low + out->low;
	}
      else
	{
	  int shorten;		/* 1-origin. Number of littlenums we drop.  */

	  shorten = in_length - out_length;
	  /* Assume out_length >= 0 ! */
	  memcpy ((void *) (out->low), (void *) (in->low + shorten),
		  ((out_length + 1) * sizeof (LITTLENUM_TYPE)));
	  out->leader = out->high;
	  out->exponent = in->exponent + shorten;
	}
    }				/* if any significant bits */
}