[issue4258] Use 30-bit digits instead of 15-bit digits for Python integers.

configure.in

 dnl ***********************************************
 dnl * Please run autoreconf to test your changes! *
 dnl ***********************************************
 dnl NOTE: autoconf 2.64 doesn't seem to work (use 2.61).
 
 # Set VERSION so we only need to edit in one place (i.e., here)
 m4_define(PYTHON_VERSION, 3.1)
 
 AC_REVISION($Revision: 68924 $)
 AC_PREREQ(2.61)
@@ skipping 1270 matching lines @@
 #endif
 EOF
 
 # Type availability checks
 AC_TYPE_MODE_T
 AC_TYPE_OFF_T
 AC_TYPE_PID_T
 AC_TYPE_SIGNAL
 AC_TYPE_SIZE_T
 AC_TYPE_UID_T
+AC_TYPE_UINT32_T
+AC_TYPE_UINT64_T
+AC_TYPE_INT32_T
+AC_TYPE_INT64_T
 AC_CHECK_TYPE(ssize_t,
   AC_DEFINE(HAVE_SSIZE_T, 1, Define if your compiler provides ssize_t),,)
 
 # Sizes of various common basic types
 # ANSI C requires sizeof(char) == 1, so no need to check it
 AC_CHECK_SIZEOF(int, 4)
 AC_CHECK_SIZEOF(long, 4)
 AC_CHECK_SIZEOF(void *, 4)
 AC_CHECK_SIZEOF(short, 2)
 AC_CHECK_SIZEOF(float, 4)
@@ skipping 1817 matching lines @@
 then
   AC_DEFINE(TANH_PRESERVES_ZERO_SIGN, 1,
   [Define if tanh(-0.) is -0., or if platform doesn't have signed zeros])
 fi
 
 AC_CHECK_FUNCS([acosh asinh atanh copysign expm1 finite hypot log1p])
 AC_CHECK_DECLS([isinf, isnan, isfinite], [], [], [[#include <math.h>]])
 
 LIBS=$LIBS_SAVE
 
+# determine what size digit to use for Python's longs

[Martin v. Löwis, 2009/02/17 22:39:18]

I'm skeptical (-0) that we really need to have such a configure option.

[dickinsm, 2009/02/18 17:06:33]

I think it's potentially useful to be able to do --disable-big-digits
on platforms where the compiler isn't smart enough to translate
a 32-bit by 32-bit multiply into the appropriate CPU instruction,
so that using 30-bit digits might hurt performance.

I've also found it handy during debugging and testing.  But I guess
I'm only +0.5 on the configure option;  if others think that it's just
unnecessary clutter then I'll remove it.

+AC_MSG_CHECKING([digit size for Python's longs])
+AC_ARG_ENABLE(big-digits,
+AC_HELP_STRING([--enable-big-digits@<:@=BITS@:>@],[use big digits for Python longs [[BITS=30]]]),
+[case $enable_big_digits in
+yes)
+  enable_big_digits=30 ;;
+no)
+  enable_big_digits=15 ;;
+[15|30])
+  ;;
+*)
+  AC_MSG_ERROR([bad value $enable_big_digits for --enable-big-digits; value should be 15 or 30]) ;;
+esac
+AC_MSG_RESULT($enable_big_digits)
+AC_DEFINE_UNQUOTED(PYLONG_DIGIT_SIZE, $enable_big_digits, [Define as the preferred size in bits of long digits])
+],
+[AC_MSG_RESULT(no value specified)])
+
 # check for wchar.h
 AC_CHECK_HEADER(wchar.h, [
   AC_DEFINE(HAVE_WCHAR_H, 1,·
   [Define if the compiler provides a wchar.h header file.])·
   wchar_h="yes"
 ],
 wchar_h="no"
 )
 
 # determine wchar_t size
@@ skipping 569 matching lines @@
 if test ! -f Modules/Setup.local
 then
         echo "# Edit this file for local setup changes" >Modules/Setup.local
 fi
 
 echo "creating Makefile"
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
                         -s Modules Modules/Setup.config \
                         Modules/Setup.local Modules/Setup
 mv config.c Modules