Refactor *cvt functions implementation (1/2)

This patch refactors the *cvt functions implementation in a way that
makes it easier to re-use them for implementing the IEEE long double on
powerpc64le.  By splitting the implementation per se in one file
(efgcvt-template.c) and the alias definitions in others (e.g. efgcvt.c),
the new code makes it easier to define new function names, such as
__qecvtieee128.

Tested that installed stripped binaries for all build-many-glibcs
targets remain identical before and after this patch.  Also tested for
powerpc64le and x86_64.

Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>

8 files changed, 424 insertions, 385 deletions

diff --git a/misc/efgcvt-dbl-macros.h b/misc/efgcvt-dbl-macros.h
new file mode 100644
index 0000000000..17e01e77e3
--- /dev/null
+++ b/misc/efgcvt-dbl-macros.h
@@ -0,0 +1,52 @@
+/* Macros for the implementation of *cvt functions, double version.
+   Copyright (C) 1995-2019 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/>.  */
+
+#include <float.h>
+
+#define FLOAT_TYPE double
+#define FUNC_PREFIX
+#define FLOAT_FMT_FLAG
+#define FLOAT_NAME_EXT
+#define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
+/* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
+   don't have log10 available in the preprocessor.  */
+#define MAXDIG (NDIGIT_MAX + 3)
+#define FCVT_MAXDIG (DBL_MAX_10_EXP + MAXDIG)
+#if DBL_MANT_DIG == 53
+# define NDIGIT_MAX 17
+#elif DBL_MANT_DIG == 24
+# define NDIGIT_MAX 9
+#elif DBL_MANT_DIG == 56
+# define NDIGIT_MAX 18
+#else
+/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
+   compile time constant here, so we cannot use it.  */
+# error "NDIGIT_MAX must be precomputed"
+# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
+#endif
+#if DBL_MIN_10_EXP == -37
+# define FLOAT_MIN_10_NORM	1.0e-37
+#elif DBL_MIN_10_EXP == -307
+# define FLOAT_MIN_10_NORM	1.0e-307
+#elif DBL_MIN_10_EXP == -4931
+# define FLOAT_MIN_10_NORM	1.0e-4931
+#else
+/* libc can't depend on libm.  */
+# error "FLOAT_MIN_10_NORM must be precomputed"
+# define FLOAT_MIN_10_NORM	exp10 (DBL_MIN_10_EXP)
+#endif
diff --git a/misc/efgcvt-ldbl-macros.h b/misc/efgcvt-ldbl-macros.h
new file mode 100644
index 0000000000..38470d93ab
--- /dev/null
+++ b/misc/efgcvt-ldbl-macros.h
@@ -0,0 +1,59 @@
+/* Macros for the implementation of *cvt functions, long double version.
+   Copyright (C) 1996-2019 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/>.  */
+
+#include <float.h>
+
+#define FLOAT_TYPE long double
+#define FUNC_PREFIX q
+#define FLOAT_FMT_FLAG "L"
+#define FLOAT_NAME_EXT l
+#define FLOAT_MIN_10_EXP LDBL_MIN_10_EXP
+/* Actually we have to write (LDBL_DIG + log10 (LDBL_MAX_10_EXP)) but
+   we don't have log10 available in the preprocessor.  Since we cannot
+   assume anything on the used `long double' format be generous.  */
+#define MAXDIG (NDIGIT_MAX + 12)
+#define FCVT_MAXDIG (LDBL_MAX_10_EXP + MAXDIG)
+#if LDBL_MANT_DIG == 64
+# define NDIGIT_MAX 21
+#elif LDBL_MANT_DIG == 53
+# define NDIGIT_MAX 17
+#elif LDBL_MANT_DIG == 113
+# define NDIGIT_MAX 36
+#elif LDBL_MANT_DIG == 106
+# define NDIGIT_MAX 34
+#elif LDBL_MANT_DIG == 56
+# define NDIGIT_MAX 18
+#else
+/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
+   compile time constant here, so we cannot use it.  */
+# error "NDIGIT_MAX must be precomputed"
+# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * LDBL_MANT_DIG + 1.0)))
+#endif
+#if LDBL_MIN_10_EXP == -37
+# define FLOAT_MIN_10_NORM	1.0e-37L
+#elif LDBL_MIN_10_EXP == -291
+# define FLOAT_MIN_10_NORM	1.0e-291L
+#elif LDBL_MIN_10_EXP == -307
+# define FLOAT_MIN_10_NORM	1.0e-307L
+#elif LDBL_MIN_10_EXP == -4931
+# define FLOAT_MIN_10_NORM	1.0e-4931L
+#else
+/* libc can't depend on libm.  */
+# error "FLOAT_MIN_10_NORM must be precomputed"
+# define FLOAT_MIN_10_NORM	exp10l (LDBL_MIN_10_EXP)
+#endif
diff --git a/misc/efgcvt-template.c b/misc/efgcvt-template.c
new file mode 100644
index 0000000000..aeb4e1ea01
--- /dev/null
+++ b/misc/efgcvt-template.c
@@ -0,0 +1,78 @@
+/* Compatibility functions for floating point formatting.
+   Copyright (C) 1995-2019 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/>.  */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/param.h>
+#include <libc-lock.h>
+#include <math_ldbl_opt.h>
+
+#define APPEND(a, b) APPEND2 (a, b)
+#define APPEND2(a, b) a##b
+#define __APPEND(a, b) __APPEND2 (a, b)
+#define __APPEND2(a, b) __##a##b
+
+
+#define FCVT_BUFFER APPEND (FUNC_PREFIX, fcvt_buffer)
+#define FCVT_BUFPTR APPEND (FUNC_PREFIX, fcvt_bufptr)
+#define ECVT_BUFFER APPEND (FUNC_PREFIX, ecvt_buffer)
+
+
+static char FCVT_BUFFER[MAXDIG];
+static char ECVT_BUFFER[MAXDIG];
+libc_freeres_ptr (static char *FCVT_BUFPTR);
+
+char *
+__APPEND (FUNC_PREFIX, fcvt) (FLOAT_TYPE value, int ndigit, int *decpt,
+			      int *sign)
+{
+  if (FCVT_BUFPTR == NULL)
+    {
+      if (__APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
+					  FCVT_BUFFER, MAXDIG) != -1)
+	return FCVT_BUFFER;
+
+      FCVT_BUFPTR = (char *) malloc (FCVT_MAXDIG);
+      if (FCVT_BUFPTR == NULL)
+	return FCVT_BUFFER;
+    }
+
+  (void) __APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
+					 FCVT_BUFPTR, FCVT_MAXDIG);
+
+  return FCVT_BUFPTR;
+}
+
+
+char *
+__APPEND (FUNC_PREFIX, ecvt) (FLOAT_TYPE value, int ndigit, int *decpt,
+			      int *sign)
+{
+  (void) __APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign,
+					 ECVT_BUFFER, MAXDIG);
+
+  return ECVT_BUFFER;
+}
+
+char *
+__APPEND (FUNC_PREFIX, gcvt) (FLOAT_TYPE value, int ndigit, char *buf)
+{
+  sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", MIN (ndigit, NDIGIT_MAX), value);
+  return buf;
+}
diff --git a/misc/efgcvt.c b/misc/efgcvt.c
index 492e4e8086..9021b03bca 100644
--- a/misc/efgcvt.c
+++ b/misc/efgcvt.c
@@ -1,4 +1,4 @@
-/* Compatibility functions for floating point formatting.
+/* Double versions of *cvt_r functions.
    Copyright (C) 1995-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -16,107 +16,16 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/param.h>
-#include <float.h>
-#include <libc-lock.h>
-#include <math_ldbl_opt.h>
-
-#ifndef FLOAT_TYPE
-# define FLOAT_TYPE double
-# define FUNC_PREFIX
-# define FLOAT_FMT_FLAG
-/* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
-   don't have log10 available in the preprocessor.  */
-# define MAXDIG (NDIGIT_MAX + 3)
-# define FCVT_MAXDIG (DBL_MAX_10_EXP + MAXDIG)
-# if DBL_MANT_DIG == 53
-#  define NDIGIT_MAX 17
-# elif DBL_MANT_DIG == 24
-#  define NDIGIT_MAX 9
-# elif DBL_MANT_DIG == 56
-#  define NDIGIT_MAX 18
-# else
-/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
-   compile time constant here, so we cannot use it.  */
-#  error "NDIGIT_MAX must be precomputed"
-#  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
-# endif
-#else
-# define LONG_DOUBLE_CVT
-#endif
-
-#define APPEND(a, b) APPEND2 (a, b)
-#define APPEND2(a, b) a##b
-#define __APPEND(a, b) __APPEND2 (a, b)
-#define __APPEND2(a, b) __##a##b
-
-
-#define FCVT_BUFFER APPEND (FUNC_PREFIX, fcvt_buffer)
-#define FCVT_BUFPTR APPEND (FUNC_PREFIX, fcvt_bufptr)
-#define ECVT_BUFFER APPEND (FUNC_PREFIX, ecvt_buffer)
-
-
-static char FCVT_BUFFER[MAXDIG];
-static char ECVT_BUFFER[MAXDIG];
-libc_freeres_ptr (static char *FCVT_BUFPTR);
-
-char *
-__APPEND (FUNC_PREFIX, fcvt) (FLOAT_TYPE value, int ndigit, int *decpt,
-			      int *sign)
-{
-  if (FCVT_BUFPTR == NULL)
-    {
-      if (__APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
-					  FCVT_BUFFER, MAXDIG) != -1)
-	return FCVT_BUFFER;
-
-      FCVT_BUFPTR = (char *) malloc (FCVT_MAXDIG);
-      if (FCVT_BUFPTR == NULL)
-	return FCVT_BUFFER;
-    }
-
-  (void) __APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
-					 FCVT_BUFPTR, FCVT_MAXDIG);
-
-  return FCVT_BUFPTR;
-}
-
-
-char *
-__APPEND (FUNC_PREFIX, ecvt) (FLOAT_TYPE value, int ndigit, int *decpt,
-			      int *sign)
-{
-  (void) __APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign,
-					 ECVT_BUFFER, MAXDIG);
-
-  return ECVT_BUFFER;
-}
-
-char *
-__APPEND (FUNC_PREFIX, gcvt) (FLOAT_TYPE value, int ndigit, char *buf)
-{
-  sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", MIN (ndigit, NDIGIT_MAX), value);
-  return buf;
-}
+#include <efgcvt-dbl-macros.h>
+#include <efgcvt-template.c>
 
 #if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
-# ifdef LONG_DOUBLE_CVT
-#  define cvt_symbol(symbol) \
-  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
-	      APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
-#  define cvt_symbol_1(lib, local, symbol, version) \
-    versioned_symbol (lib, local, symbol, version)
-# else
-#  define cvt_symbol(symbol) \
+# define cvt_symbol(symbol) \
   cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
 	      APPEND (q, symbol), GLIBC_2_0); \
   strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
-#  define cvt_symbol_1(lib, local, symbol, version) \
+# define cvt_symbol_1(lib, local, symbol, version) \
   compat_symbol (lib, local, symbol, version)
-# endif
 #else
 # define cvt_symbol(symbol) \
   strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
diff --git a/misc/efgcvt_r-template.c b/misc/efgcvt_r-template.c
new file mode 100644
index 0000000000..1cd335afe7
--- /dev/null
+++ b/misc/efgcvt_r-template.c
@@ -0,0 +1,196 @@
+/* Compatibility functions for floating point formatting, reentrant versions.
+   Copyright (C) 1995-2019 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/>.  */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <math.h>
+#include <stdlib.h>
+#include <sys/param.h>
+#include <math_ldbl_opt.h>
+
+
+#define APPEND(a, b) APPEND2 (a, b)
+#define APPEND2(a, b) a##b
+#define __APPEND(a, b) __APPEND2 (a, b)
+#define __APPEND2(a, b) __##a##b
+
+int
+__APPEND (FUNC_PREFIX, fcvt_r) (FLOAT_TYPE value, int ndigit, int *decpt,
+				int *sign, char *buf, size_t len)
+{
+  ssize_t n;
+  ssize_t i;
+  int left;
+
+  if (buf == NULL)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  left = 0;
+  if (isfinite (value))
+    {
+      *sign = signbit (value) != 0;
+      if (*sign)
+	value = -value;
+
+      if (ndigit < 0)
+	{
+	  /* Rounding to the left of the decimal point.  */
+	  while (ndigit < 0)
+	    {
+	      FLOAT_TYPE new_value = value * 0.1;
+
+	      if (new_value < 1.0)
+		{
+		  ndigit = 0;
+		  break;
+		}
+
+	      value = new_value;
+	      ++left;
+	      ++ndigit;
+	    }
+	}
+    }
+  else
+    /* Value is Inf or NaN.  */
+    *sign = 0;
+
+  n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX),
+		  value);
+  /* Check for a too small buffer.  */
+  if (n >= (ssize_t) len)
+    return -1;
+
+  i = 0;
+  while (i < n && isdigit (buf[i]))
+    ++i;
+  *decpt = i;
+
+  if (i == 0)
+    /* Value is Inf or NaN.  */
+    return 0;
+
+  if (i < n)
+    {
+      do
+	++i;
+      while (i < n && !isdigit (buf[i]));
+
+      if (*decpt == 1 && buf[0] == '0' && value != 0.0)
+	{
+	  /* We must not have leading zeroes.  Strip them all out and
+	     adjust *DECPT if necessary.  */
+	  --*decpt;
+	  while (i < n && buf[i] == '0')
+	    {
+	      --*decpt;
+	      ++i;
+	    }
+	}
+
+      memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i);
+      buf[n - (i - MAX (*decpt, 0))] = '\0';
+    }
+
+  if (left)
+    {
+      *decpt += left;
+      if ((ssize_t) --len > n)
+	{
+	  while (left-- > 0 && n < (ssize_t) len)
+	    buf[n++] = '0';
+	  buf[n] = '\0';
+	}
+    }
+
+  return 0;
+}
+
+int
+__APPEND (FUNC_PREFIX, ecvt_r) (FLOAT_TYPE value, int ndigit, int *decpt,
+				int *sign, char *buf, size_t len)
+{
+  int exponent = 0;
+
+  if (isfinite (value) && value != 0.0)
+    {
+      /* Slow code that doesn't require -lm functions.  */
+      FLOAT_TYPE d;
+      FLOAT_TYPE f = 1.0;
+      if (value < 0.0)
+	d = -value;
+      else
+	d = value;
+      /* For denormalized numbers the d < 1.0 case below won't work,
+	 as f can overflow to +Inf.  */
+      if (d < FLOAT_MIN_10_NORM)
+	{
+	  value /= FLOAT_MIN_10_NORM;
+	  if (value < 0.0)
+	    d = -value;
+	  else
+	    d = value;
+	  exponent += FLOAT_MIN_10_EXP;
+	}
+      if (d < 1.0)
+	{
+	  do
+	    {
+	      f *= 10.0;
+	      --exponent;
+	    }
+	  while (d * f < 1.0);
+
+	  value *= f;
+	}
+      else if (d >= 10.0)
+	{
+	  do
+	    {
+	      f *= 10;
+	      ++exponent;
+	    }
+	  while (d >= f * 10.0);
+
+	  value /= f;
+	}
+    }
+  else if (value == 0.0)
+    /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0.
+       This could be changed to -1 if we want to return 0.  */
+    exponent = 0;
+
+  if (ndigit <= 0 && len > 0)
+    {
+      buf[0] = '\0';
+      *decpt = 1;
+      *sign = isfinite (value) ? signbit (value) != 0 : 0;
+    }
+  else
+    if (__APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1,
+					decpt, sign, buf, len))
+      return -1;
+
+  *decpt += exponent;
+  return 0;
+}
diff --git a/misc/efgcvt_r.c b/misc/efgcvt_r.c
index 981249850c..ad78f153ba 100644
--- a/misc/efgcvt_r.c
+++ b/misc/efgcvt_r.c
@@ -1,4 +1,4 @@
-/* Compatibility functions for floating point formatting, reentrant versions.
+/* Double versions of reentrant *cvt_r functions.
    Copyright (C) 1995-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -16,241 +16,17 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <float.h>
-#include <stdio.h>
-#include <string.h>
-#include <ctype.h>
-#include <math.h>
-#include <stdlib.h>
-#include <sys/param.h>
-#include <math_ldbl_opt.h>
-
-#ifndef FLOAT_TYPE
-# define FLOAT_TYPE double
-# define FUNC_PREFIX
-# define FLOAT_FMT_FLAG
-# define FLOAT_NAME_EXT
-# define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
-# if DBL_MANT_DIG == 53
-#  define NDIGIT_MAX 17
-# elif DBL_MANT_DIG == 24
-#  define NDIGIT_MAX 9
-# elif DBL_MANT_DIG == 56
-#  define NDIGIT_MAX 18
-# else
-/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
-   compile time constant here, so we cannot use it.  */
-#  error "NDIGIT_MAX must be precomputed"
-#  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
-# endif
-# if DBL_MIN_10_EXP == -37
-#  define FLOAT_MIN_10_NORM	1.0e-37
-# elif DBL_MIN_10_EXP == -307
-#  define FLOAT_MIN_10_NORM	1.0e-307
-# elif DBL_MIN_10_EXP == -4931
-#  define FLOAT_MIN_10_NORM	1.0e-4931
-# else
-/* libc can't depend on libm.  */
-#  error "FLOAT_MIN_10_NORM must be precomputed"
-#  define FLOAT_MIN_10_NORM	exp10 (DBL_MIN_10_EXP)
-# endif
-#else
-# define LONG_DOUBLE_CVT
-#endif
-
-#define APPEND(a, b) APPEND2 (a, b)
-#define APPEND2(a, b) a##b
-#define __APPEND(a, b) __APPEND2 (a, b)
-#define __APPEND2(a, b) __##a##b
-
-#define FLOOR APPEND(floor, FLOAT_NAME_EXT)
-#define FABS APPEND(fabs, FLOAT_NAME_EXT)
-#define LOG10 APPEND(log10, FLOAT_NAME_EXT)
-#define EXP APPEND(exp, FLOAT_NAME_EXT)
-
-
-int
-__APPEND (FUNC_PREFIX, fcvt_r) (FLOAT_TYPE value, int ndigit, int *decpt,
-				int *sign, char *buf, size_t len)
-{
-  ssize_t n;
-  ssize_t i;
-  int left;
-
-  if (buf == NULL)
-    {
-      __set_errno (EINVAL);
-      return -1;
-    }
-
-  left = 0;
-  if (isfinite (value))
-    {
-      *sign = signbit (value) != 0;
-      if (*sign)
-	value = -value;
-
-      if (ndigit < 0)
-	{
-	  /* Rounding to the left of the decimal point.  */
-	  while (ndigit < 0)
-	    {
-	      FLOAT_TYPE new_value = value * 0.1;
-
-	      if (new_value < 1.0)
-		{
-		  ndigit = 0;
-		  break;
-		}
-
-	      value = new_value;
-	      ++left;
-	      ++ndigit;
-	    }
-	}
-    }
-  else
-    /* Value is Inf or NaN.  */
-    *sign = 0;
-
-  n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX),
-		  value);
-  /* Check for a too small buffer.  */
-  if (n >= (ssize_t) len)
-    return -1;
-
-  i = 0;
-  while (i < n && isdigit (buf[i]))
-    ++i;
-  *decpt = i;
-
-  if (i == 0)
-    /* Value is Inf or NaN.  */
-    return 0;
-
-  if (i < n)
-    {
-      do
-	++i;
-      while (i < n && !isdigit (buf[i]));
-
-      if (*decpt == 1 && buf[0] == '0' && value != 0.0)
-	{
-	  /* We must not have leading zeroes.  Strip them all out and
-	     adjust *DECPT if necessary.  */
-	  --*decpt;
-	  while (i < n && buf[i] == '0')
-	    {
-	      --*decpt;
-	      ++i;
-	    }
-	}
-
-      memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i);
-      buf[n - (i - MAX (*decpt, 0))] = '\0';
-    }
-
-  if (left)
-    {
-      *decpt += left;
-      if ((ssize_t) --len > n)
-	{
-	  while (left-- > 0 && n < (ssize_t) len)
-	    buf[n++] = '0';
-	  buf[n] = '\0';
-	}
-    }
-
-  return 0;
-}
-
-int
-__APPEND (FUNC_PREFIX, ecvt_r) (FLOAT_TYPE value, int ndigit, int *decpt,
-				int *sign, char *buf, size_t len)
-{
-  int exponent = 0;
-
-  if (isfinite (value) && value != 0.0)
-    {
-      /* Slow code that doesn't require -lm functions.  */
-      FLOAT_TYPE d;
-      FLOAT_TYPE f = 1.0;
-      if (value < 0.0)
-	d = -value;
-      else
-	d = value;
-      /* For denormalized numbers the d < 1.0 case below won't work,
-	 as f can overflow to +Inf.  */
-      if (d < FLOAT_MIN_10_NORM)
-	{
-	  value /= FLOAT_MIN_10_NORM;
-	  if (value < 0.0)
-	    d = -value;
-	  else
-	    d = value;
-	  exponent += FLOAT_MIN_10_EXP;
-	}
-      if (d < 1.0)
-	{
-	  do
-	    {
-	      f *= 10.0;
-	      --exponent;
-	    }
-	  while (d * f < 1.0);
-
-	  value *= f;
-	}
-      else if (d >= 10.0)
-	{
-	  do
-	    {
-	      f *= 10;
-	      ++exponent;
-	    }
-	  while (d >= f * 10.0);
-
-	  value /= f;
-	}
-    }
-  else if (value == 0.0)
-    /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0.
-       This could be changed to -1 if we want to return 0.  */
-    exponent = 0;
-
-  if (ndigit <= 0 && len > 0)
-    {
-      buf[0] = '\0';
-      *decpt = 1;
-      *sign = isfinite (value) ? signbit (value) != 0 : 0;
-    }
-  else
-    if (__APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1,
-					decpt, sign, buf, len))
-      return -1;
-
-  *decpt += exponent;
-  return 0;
-}
+#include <efgcvt-dbl-macros.h>
+#include <efgcvt_r-template.c>
 
 #if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
-# ifdef LONG_DOUBLE_CVT
-#  define cvt_symbol(symbol) \
-  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
-	      APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
-#  define cvt_symbol_1(lib, local, symbol, version) \
-    libc_hidden_def (local) \
-    versioned_symbol (lib, local, symbol, version)
-# else
-#  define cvt_symbol(symbol) \
+# define cvt_symbol(symbol) \
   cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
 	      APPEND (q, symbol), GLIBC_2_0); \
   weak_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
-#  define cvt_symbol_1(lib, local, symbol, version) \
+# define cvt_symbol_1(lib, local, symbol, version) \
   libc_hidden_def (local) \
   compat_symbol (lib, local, symbol, version)
-# endif
 #else
 # define cvt_symbol(symbol) \
   cvt_symbol_1 (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
diff --git a/misc/qefgcvt.c b/misc/qefgcvt.c
index 4fcadfcdc2..8f1582a50e 100644
--- a/misc/qefgcvt.c
+++ b/misc/qefgcvt.c
@@ -16,31 +16,19 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <float.h>
+#include <efgcvt-ldbl-macros.h>
+#include <efgcvt-template.c>
 
-#define FLOAT_TYPE long double
-#define FUNC_PREFIX q
-#define FLOAT_FMT_FLAG "L"
-/* Actually we have to write (LDBL_DIG + log10 (LDBL_MAX_10_EXP)) but
-   we don't have log10 available in the preprocessor.  Since we cannot
-   assume anything on the used `long double' format be generous.  */
-#define MAXDIG (NDIGIT_MAX + 12)
-#define FCVT_MAXDIG (LDBL_MAX_10_EXP + MAXDIG)
-#if LDBL_MANT_DIG == 64
-# define NDIGIT_MAX 21
-#elif LDBL_MANT_DIG == 53
-# define NDIGIT_MAX 17
-#elif LDBL_MANT_DIG == 113
-# define NDIGIT_MAX 36
-#elif LDBL_MANT_DIG == 106
-# define NDIGIT_MAX 34
-#elif LDBL_MANT_DIG == 56
-# define NDIGIT_MAX 18
+#if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
+# define cvt_symbol(symbol) \
+  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
+	      APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
+# define cvt_symbol_1(lib, local, symbol, version) \
+    versioned_symbol (lib, local, symbol, version)
 #else
-/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
-   compile time constant here, so we cannot use it.  */
-# error "NDIGIT_MAX must be precomputed"
-# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * LDBL_MANT_DIG + 1.0)))
+# define cvt_symbol(symbol) \
+  strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
 #endif
-
-#include "efgcvt.c"
+cvt_symbol(fcvt);
+cvt_symbol(ecvt);
+cvt_symbol(gcvt);
diff --git a/misc/qefgcvt_r.c b/misc/qefgcvt_r.c
index 8f4d8b9f7a..4240f1da2b 100644
--- a/misc/qefgcvt_r.c
+++ b/misc/qefgcvt_r.c
@@ -17,41 +17,22 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <float.h>
+#include <efgcvt-ldbl-macros.h>
+#include <efgcvt_r-template.c>
 
-#define FLOAT_TYPE long double
-#define FUNC_PREFIX q
-#define FLOAT_FMT_FLAG "L"
-#define FLOAT_NAME_EXT l
-#define FLOAT_MIN_10_EXP LDBL_MIN_10_EXP
-#if LDBL_MANT_DIG == 64
-# define NDIGIT_MAX 21
-#elif LDBL_MANT_DIG == 53
-# define NDIGIT_MAX 17
-#elif LDBL_MANT_DIG == 113
-# define NDIGIT_MAX 36
-#elif LDBL_MANT_DIG == 106
-# define NDIGIT_MAX 34
-#elif LDBL_MANT_DIG == 56
-# define NDIGIT_MAX 18
+#if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
+# define cvt_symbol(symbol) \
+  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
+	      APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
+# define cvt_symbol_1(lib, local, symbol, version) \
+  libc_hidden_def (local) \
+  versioned_symbol (lib, local, symbol, version)
 #else
-/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
-   compile time constant here, so we cannot use it.  */
-# error "NDIGIT_MAX must be precomputed"
-# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * LDBL_MANT_DIG + 1.0)))
+# define cvt_symbol(symbol) \
+  cvt_symbol_1 (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
+#  define cvt_symbol_1(local, symbol) \
+  libc_hidden_def (local) \
+  weak_alias (local, symbol)
 #endif
-#if LDBL_MIN_10_EXP == -37
-# define FLOAT_MIN_10_NORM	1.0e-37L
-#elif LDBL_MIN_10_EXP == -291
-# define FLOAT_MIN_10_NORM	1.0e-291L
-#elif LDBL_MIN_10_EXP == -307
-# define FLOAT_MIN_10_NORM	1.0e-307L
-#elif LDBL_MIN_10_EXP == -4931
-# define FLOAT_MIN_10_NORM	1.0e-4931L
-#else
-/* libc can't depend on libm.  */
-# error "FLOAT_MIN_10_NORM must be precomputed"
-# define FLOAT_MIN_10_NORM	exp10l (LDBL_MIN_10_EXP)
-#endif
-
-#include "efgcvt_r.c"
+cvt_symbol(fcvt_r);
+cvt_symbol(ecvt_r);