2.5-18.1

1 files changed, 175 insertions, 0 deletions

diff --git a/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c b/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c
new file mode 100644
index 0000000000..18a2e671ad
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c
@@ -0,0 +1,175 @@
+/* Copyright (C) 1995,1996,1997,1998,1999,2002,2003,2006
+	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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+#include <ieee754.h>
+#include <float.h>
+#include <math.h>
+#include <stdlib.h>
+
+/* Convert a `long double' in IBM extended format to a multi-precision
+   integer representing the significand scaled up by its number of
+   bits (106 for long double) and an integral power of two (MPN
+   frexpl). */
+
+mp_size_t
+__mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
+			   int *expt, int *is_neg,
+			   long double value)
+{
+  union ibm_extended_long_double u;
+  unsigned long long hi, lo;
+  int ediff;
+  u.d = value;
+
+  *is_neg = u.ieee.negative;
+  *expt = (int) u.ieee.exponent - IBM_EXTENDED_LONG_DOUBLE_BIAS;
+
+  lo = ((long long) u.ieee.mantissa2 << 32) | u.ieee.mantissa3;
+  hi = ((long long) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
+  /* If the lower double is not a denomal or zero then set the hidden
+     53rd bit.  */
+  if (u.ieee.exponent2 > 0)
+    {
+      lo |= 1LL << 52;
+
+      /* The lower double is normalized separately from the upper.  We may
+	 need to adjust the lower manitissa to reflect this.  */
+      ediff = u.ieee.exponent - u.ieee.exponent2;
+      if (ediff > 53)
+	lo = lo >> (ediff-53);
+    }
+  /* The high double may be rounded and the low double reflects the
+     difference between the long double and the rounded high double
+     value.  This is indicated by a differnce between the signs of the
+     high and low doubles.  */
+  if ((u.ieee.negative != u.ieee.negative2)
+      && ((u.ieee.exponent2 != 0) && (lo != 0L)))
+    {
+      lo = (1ULL << 53) - lo;
+      if (hi == 0LL)
+	{
+	  /* we have a borrow from the hidden bit, so shift left 1.  */
+	  hi = 0x0ffffffffffffeLL | (lo >> 51);
+	  lo = 0x1fffffffffffffLL & (lo << 1);
+	  (*expt)--;
+	}
+      else
+	hi--;
+    }
+#if BITS_PER_MP_LIMB == 32
+  /* Combine the mantissas to be contiguous.  */
+  res_ptr[0] = lo;
+  res_ptr[1] = (hi << (53 - 32)) | (lo >> 32);
+  res_ptr[2] = hi >> 11;
+  res_ptr[3] = hi >> (32 + 11);
+  #define N 4
+#elif BITS_PER_MP_LIMB == 64
+  /* Combine the two mantissas to be contiguous.  */
+  res_ptr[0] = (hi << 53) | lo;
+  res_ptr[1] = hi >> 11;
+  #define N 2
+#else
+  #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
+#endif
+/* The format does not fill the last limb.  There are some zeros.  */
+#define NUM_LEADING_ZEROS (BITS_PER_MP_LIMB \
+			   - (LDBL_MANT_DIG - ((N - 1) * BITS_PER_MP_LIMB)))
+
+  if (u.ieee.exponent == 0)
+    {
+      /* A biased exponent of zero is a special case.
+	 Either it is a zero or it is a denormal number.  */
+      if (res_ptr[0] == 0 && res_ptr[1] == 0
+	  && res_ptr[N - 2] == 0 && res_ptr[N - 1] == 0) /* Assumes N<=4.  */
+	/* It's zero.  */
+	*expt = 0;
+      else
+	{
+	  /* It is a denormal number, meaning it has no implicit leading
+  	     one bit, and its exponent is in fact the format minimum.  */
+	  int cnt;
+
+#if N == 2
+	  if (res_ptr[N - 1] != 0)
+	    {
+	      count_leading_zeros (cnt, res_ptr[N - 1]);
+	      cnt -= NUM_LEADING_ZEROS;
+	      res_ptr[N - 1] = res_ptr[N - 1] << cnt
+			       | (res_ptr[0] >> (BITS_PER_MP_LIMB - cnt));
+	      res_ptr[0] <<= cnt;
+	      *expt = LDBL_MIN_EXP - 1 - cnt;
+	    }
+	  else
+	    {
+	      count_leading_zeros (cnt, res_ptr[0]);
+	      if (cnt >= NUM_LEADING_ZEROS)
+		{
+		  res_ptr[N - 1] = res_ptr[0] << (cnt - NUM_LEADING_ZEROS);
+		  res_ptr[0] = 0;
+		}
+	      else
+		{
+		  res_ptr[N - 1] = res_ptr[0] >> (NUM_LEADING_ZEROS - cnt);
+		  res_ptr[0] <<= BITS_PER_MP_LIMB - (NUM_LEADING_ZEROS - cnt);
+		}
+	      *expt = LDBL_MIN_EXP - 1
+		- (BITS_PER_MP_LIMB - NUM_LEADING_ZEROS) - cnt;
+	    }
+#else
+	  int j, k, l;
+
+	  for (j = N - 1; j > 0; j--)
+	    if (res_ptr[j] != 0)
+	      break;
+
+	  count_leading_zeros (cnt, res_ptr[j]);
+	  cnt -= NUM_LEADING_ZEROS;
+	  l = N - 1 - j;
+	  if (cnt < 0)
+	    {
+	      cnt += BITS_PER_MP_LIMB;
+	      l--;
+	    }
+	  if (!cnt)
+	    for (k = N - 1; k >= l; k--)
+	      res_ptr[k] = res_ptr[k-l];
+	  else
+	    {
+	      for (k = N - 1; k > l; k--)
+		res_ptr[k] = res_ptr[k-l] << cnt
+			     | res_ptr[k-l-1] >> (BITS_PER_MP_LIMB - cnt);
+	      res_ptr[k--] = res_ptr[0] << cnt;
+	    }
+
+	  for (; k >= 0; k--)
+	    res_ptr[k] = 0;
+	  *expt = LDBL_MIN_EXP - 1 - l * BITS_PER_MP_LIMB - cnt;
+#endif
+	}
+    }
+  else
+    /* Add the implicit leading one bit for a normalized number.  */
+    res_ptr[N - 1] |= (mp_limb_t) 1 << (LDBL_MANT_DIG - 1
+					- ((N - 1) * BITS_PER_MP_LIMB));
+
+  return N;
+}