new module 'floorl'

[Bruno Haible]

Here's the module for the floorl() function. Very much like the truncl()
function.

Paolo, this replaces the floorl part of the 'mathl' module. I think the
following changes are all improvements:
  - Don't assume that LDBL_EPSILON is a power of two. If LDBL_EPSILON
    is not a power of two, I think the rounding will be incorrect for
    some numbers between 0.5/LDBL_EPSILON and 1.0/LDBL_EPSILON.
  - Forbid compiler optimizations: Compilers are allowed to rearrange
      y = 1.0L / LDBL_EPSILON + x - 1.0 / LDBL_EPSILON;
    into
      y = x,
    which would obviously break the function.
  - In math.h, do a "#define floorl rpl_floorl", in order to avoid
    possible undesired compiler optimizations.


2007-10-04  Bruno Haible  <address@hidden>

        * modules/floorl: New file.
        * lib/floorl.c: Replace entire file.
        * m4/floorl.m4: New file.
        * lib/math.in.h (floorl): Replace declaration.
        * m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize GNULIB_FLOORL.
        * modules/math (Makefile.am): Substitute also GNULIB_FLOORL.
        * doc/functions/floorl.texi: Mention the 'floorl' module.
        * modules/mathl (Files): Remove lib/floorl.c.
        (Depends-on): Add floorl.

*** doc/functions/floorl.texi.orig      2007-10-05 03:26:02.000000000 +0200
--- doc/functions/floorl.texi   2007-10-05 03:07:12.000000000 +0200
***************
*** 4,18 ****
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/floorl.html}
  
! Gnulib module: ---
  
  Portability problems fixed by Gnulib:
  @itemize
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
- @item
- This function is missing on some platforms:
- FreeBSD 5.2.1, NetBSD 3.0, OpenBSD 3.8, HP-UX 11, IRIX 6.5, Solaris 9, 
Cygwin, Interix 3.5, BeOS.
  @end itemize
--- 4,18 ----
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/floorl.html}
  
! Gnulib module: floorl
  
  Portability problems fixed by Gnulib:
  @itemize
+ @item
+ This function is missing on some platforms:
+ FreeBSD 5.2.1, NetBSD 3.0, OpenBSD 3.8, HP-UX 11, IRIX 6.5, Solaris 9, 
Cygwin, Interix 3.5, BeOS.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @end itemize
*** lib/floorl.c.orig   2007-10-05 03:26:02.000000000 +0200
--- lib/floorl.c        2007-10-05 03:08:38.000000000 +0200
***************
*** 1,9 ****
! /* Emulation for floorl.
!    Contributed by Paolo Bonzini
! 
!    Copyright 2002, 2003, 2007 Free Software Foundation, Inc.
! 
!    This file is part of gnulib.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
--- 1,5 ----
! /* Round towards negative infinity.
!    Copyright (C) 2007 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
***************
*** 19,46 ****
     with this program; if not, write to the Free Software Foundation,
     Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  
! #include <config.h>
! 
! /* Specification.  */
! #include <math.h>
! 
! #include <float.h>
! 
! /* To compute the integer part of X, sum a big enough
!    integer so that the precision of the floating point
!    number is exactly 1.  */
! 
! long double
! floorl(long double x)
! {
!   long double y;
!   if (x < 0.0L)
!     y = -(1.0L / LDBL_EPSILON - x - 1.0 / LDBL_EPSILON);
!   else
!     y = 1.0L / LDBL_EPSILON + x - 1.0 / LDBL_EPSILON;
  
!   if (y > x)
!     return y - 1.0L;
!   else
!     return y;
! }
--- 15,21 ----
     with this program; if not, write to the Free Software Foundation,
     Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  
! /* Written by Bruno Haible <address@hidden>, 2007.  */
  
! #define USE_LONG_DOUBLE
! #include "floor.c"
*** lib/math.in.h.orig  2007-10-05 03:26:02.000000000 +0200
--- lib/math.in.h       2007-10-05 03:19:54.000000000 +0200
***************
*** 139,152 ****
       floorf (x))
  #endif
  
! #if @GNULIB_MATHL@ || address@hidden@
  extern long double floorl (long double x);
! #endif
! #if address@hidden@ && defined GNULIB_POSIXCHECK
  # undef floorl
  # define floorl(x) \
      (GL_LINK_WARNING ("floorl is unportable - " \
!                       "use gnulib module mathl for portability"), \
       floorl (x))
  #endif
  
--- 139,154 ----
       floorf (x))
  #endif
  
! #if @GNULIB_FLOORL@
! # if address@hidden@
! #  define floorl rpl_floorl
  extern long double floorl (long double x);
! # endif
! #elif defined GNULIB_POSIXCHECK
  # undef floorl
  # define floorl(x) \
      (GL_LINK_WARNING ("floorl is unportable - " \
!                       "use gnulib module floorl for portability"), \
       floorl (x))
  #endif
  
Changing permissions from . to 100644
*** m4/floorl.m4.orig   2003-09-23 19:59:22.000000000 +0200
--- m4/floorl.m4        2007-10-05 03:22:37.000000000 +0200
***************
*** 0 ****
--- 1,48 ----
+ # floorl.m4 serial 1
+ dnl Copyright (C) 2007 Free Software Foundation, Inc.
+ dnl This file is free software; the Free Software Foundation
+ dnl gives unlimited permission to copy and/or distribute it,
+ dnl with or without modifications, as long as this notice is preserved.
+ 
+ AC_DEFUN([gl_FUNC_FLOORL],
+ [
+   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+   dnl Persuade glibc <math.h> to declare floorl().
+   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+   dnl Test whether floorl() is declared.
+   AC_CHECK_DECLS([floorl], , , [#include <math.h>])
+   if test "$ac_cv_have_decl_floorl" = yes; then
+     dnl Test whether floorl() can be used without libm.
+     FLOORL_LIBM=?
+     AC_TRY_LINK([
+        #ifndef __NO_MATH_INLINES
+        # define __NO_MATH_INLINES 1 /* for glibc */
+        #endif
+        #include <math.h>
+        long double x;],
+       [x = floorl(x);],
+       [FLOORL_LIBM=])
+     if test "$FLOORL_LIBM" = "?"; then
+       save_LIBS="$LIBS"
+       LIBS="$LIBS -lm"
+       AC_TRY_LINK([
+          #ifndef __NO_MATH_INLINES
+          # define __NO_MATH_INLINES 1 /* for glibc */
+          #endif
+          #include <math.h>
+          long double x;],
+         [x = floorl(x);],
+         [FLOORL_LIBM="-lm"])
+       LIBS="$save_LIBS"
+     fi
+     if test "$FLOORL_LIBM" = "?"; then
+       FLOORL_LIBM=
+     fi
+   else
+     HAVE_DECL_FLOORL=0
+     AC_LIBOBJ([floorl])
+     FLOORL_LIBM=
+   fi
+   AC_SUBST([HAVE_DECL_FLOORL])
+   AC_SUBST([FLOORL_LIBM])
+ ])
*** m4/math_h.m4.orig   2007-10-05 03:26:02.000000000 +0200
--- m4/math_h.m4        2007-10-05 03:18:35.000000000 +0200
***************
*** 20,25 ****
--- 20,26 ----
  AC_DEFUN([gl_MATH_H_DEFAULTS],
  [
    GNULIB_FLOORF=0;  AC_SUBST([GNULIB_FLOORF])
+   GNULIB_FLOORL=0;  AC_SUBST([GNULIB_FLOORL])
    GNULIB_FREXP=0;   AC_SUBST([GNULIB_FREXP])
    GNULIB_FREXPL=0;  AC_SUBST([GNULIB_FREXPL])
    GNULIB_LDEXPL=0;  AC_SUBST([GNULIB_LDEXPL])
Changing permissions from . to 100644
*** modules/floorl.orig 2003-09-23 19:59:22.000000000 +0200
--- modules/floorl      2007-10-05 03:11:34.000000000 +0200
***************
*** 0 ****
--- 1,31 ----
+ Description:
+ floorl() function: round towards negative infinity.
+ 
+ Files:
+ lib/floorl.c
+ lib/floor.c
+ m4/floorl.m4
+ 
+ Depends-on:
+ math
+ extensions
+ float
+ 
+ configure.ac:
+ gl_FUNC_FLOORL
+ gl_MATH_MODULE_INDICATOR([floorl])
+ 
+ Makefile.am:
+ 
+ Include:
+ <math.h>
+ 
+ Link:
+ $(FLOORL_LIBM)
+ 
+ License:
+ LGPL
+ 
+ Maintainer:
+ Bruno Haible
+ 
*** modules/math.orig   2007-10-05 03:26:02.000000000 +0200
--- modules/math        2007-10-05 03:18:23.000000000 +0200
***************
*** 23,28 ****
--- 23,29 ----
          sed -e 's/@''INCLUDE_NEXT''@/$(INCLUDE_NEXT)/g' \
              -e 's|@''NEXT_MATH_H''@|$(NEXT_MATH_H)|g' \
              -e 's|@''GNULIB_FLOORF''@|$(GNULIB_FLOORF)|g' \
+             -e 's|@''GNULIB_FLOORL''@|$(GNULIB_FLOORL)|g' \
              -e 's|@''GNULIB_FREXP''@|$(GNULIB_FREXP)|g' \
              -e 's|@''GNULIB_FREXPL''@|$(GNULIB_FREXPL)|g' \
              -e 's|@''GNULIB_LDEXPL''@|$(GNULIB_LDEXPL)|g' \
*** modules/mathl.orig  2007-10-05 03:26:02.000000000 +0200
--- modules/mathl       2007-10-05 03:17:20.000000000 +0200
***************
*** 8,14 ****
  lib/ceill.c
  lib/cosl.c
  lib/expl.c
- lib/floorl.c
  lib/logl.c
  lib/sincosl.c
  lib/sinl.c
--- 8,13 ----
***************
*** 24,29 ****
--- 23,29 ----
  frexpl
  isnanl
  ldexpl
+ floorl
  
  configure.ac:
  gl_FUNC_LONG_DOUBLE_MATH