?RCS: $Id: byteorder.U,v 3.0.1.2 1997/02/28 15:24:55 ram Exp $
?RCS:
?RCS: Copyright (c) 1991-1993, Raphael Manfredi
?RCS: 
?RCS: You may redistribute only under the terms of the Artistic Licence,
?RCS: as specified in the README file that comes with the distribution.
?RCS: You may reuse parts of this distribution only within the terms of
?RCS: that same Artistic Licence; a copy of which may be found at the root
?RCS: of the source tree for dist 3.0.
?RCS:
?RCS: $Log: byteorder.U,v $
?RCS: Revision 3.0.1.2  1997/02/28  15:24:55  ram
?RCS: patch61: no longer ask the user if the test runs ok
?RCS:
?RCS: Revision 3.0.1.1  1994/10/29  16:02:58  ram
?RCS: patch36: added ?F: line for metalint file checking
?RCS:
?RCS: Revision 3.0  1993/08/18  12:05:28  ram
?RCS: Baseline for dist 3.0 netwide release.
?RCS:
?MAKE:byteorder: cat Myread Oldconfig Loc Compile rm run \
	usecrosscompile multiarch uvtype uvsize i_stdlib
?MAKE:	-pick add $@ %<
?S:byteorder:
?S:	This variable holds the byte order in a UV. In the following,
?S:	larger digits indicate more significance.  The variable byteorder
?S:	is either 4321 on a big-endian machine, or 1234 on a little-endian,
?S:	or 87654321 on a Cray ... or 3412 with weird order !
?S:.
?C:BYTEORDER:
?C:	This symbol holds the hexadecimal constant defined in byteorder,
?C:	in a UV, i.e. 0x1234 or 0x4321 or 0x12345678, etc...
?C:	If the compiler supports cross-compiling or multiple-architecture
?C:	binaries (eg. on NeXT systems), use compiler-defined macros to
?C:	determine the byte order.
?C:	On NeXT 3.2 (and greater), you can build "Fat" Multiple Architecture
?C:	Binaries (MAB) on either big endian or little endian machines.
?C:	The endian-ness is available at compile-time.  This only matters
?C:	for perl, where the config.h can be generated and installed on 
?C:	one system, and used by a different architecture to build an
?C:	extension.  Older versions of NeXT that might not have
?C:	defined either *_ENDIAN__ were all on Motorola 680x0 series,
?C:	so the default case (for NeXT) is big endian to catch them. 
?C:	This might matter for NeXT 3.0.
?C:.
?H:?%<:#if defined(USE_CROSS_COMPILE) || defined(MULTIARCH)
?H:?%<:#  ifdef __LITTLE_ENDIAN__
?H:?%<:#    if LONGSIZE == 4
?H:?%<:#      define BYTEORDER 0x1234
?H:?%<:#    else
?H:?%<:#      if LONGSIZE == 8
?H:?%<:#        define BYTEORDER 0x12345678
?H:?%<:#      endif
?H:?%<:#    endif
?H:?%<:#  else
?H:?%<:#    ifdef __BIG_ENDIAN__
?H:?%<:#      if LONGSIZE == 4
?H:?%<:#        define BYTEORDER 0x4321
?H:?%<:#      else
?H:?%<:#        if LONGSIZE == 8
?H:?%<:#          define BYTEORDER 0x87654321
?H:?%<:#        endif
?H:?%<:#      endif
?H:?%<:#    endif
?H:?%<:#  endif
?H:?%<:#  if !defined(BYTEORDER) && (defined(NeXT) || defined(__NeXT__))
?H:?%<:#    define BYTEORDER 0x4321
?H:?%<:#  endif
?H:?%<:#else
?H:?%<:#define BYTEORDER 0x$byteorder	/* large digits for MSB */
?H:?%<:#endif /* NeXT */
?H:.
?T:xxx_prompt
: check for ordering of bytes in a UV
echo " "
case "$usecrosscompile$multiarch" in
*$define*)
	$cat <<EOM
You seem to be either cross-compiling or doing a multiarchitecture build,
skipping the byteorder check.

EOM
	byteorder='ffff'
	;;
*)
	case "$byteorder" in
	'')
		$cat <<'EOM'
In the following, larger digits indicate more significance.  A big-endian
machine like a Pyramid or a Motorola 680?0 chip will come out to 4321. A
little-endian machine like a Vax or an Intel 80?86 chip would be 1234. Other
machines may have weird orders like 3412.  A Cray will report 87654321,
an Alpha will report 12345678. If the test program works the default is
probably right.
I'm now running the test program...
EOM
		$cat >try.c <<EOCP
#include <stdio.h>
#$i_stdlib I_STDLIB
#ifdef I_STDLIB
#include <stdlib.h>
#endif
#include <sys/types.h>
typedef $uvtype UV;
int main()
{
	int i;
	union {
		UV l;
		char c[$uvsize];
	} u;

	if ($uvsize > 4)
		u.l = (((UV)0x08070605) << 32) | (UV)0x04030201;
	else
		u.l = (UV)0x04030201;
	for (i = 0; i < $uvsize; i++)
		printf("%c", u.c[i]+'0');
	printf("\n");
	exit(0);
}
EOCP
		xxx_prompt=y
		set try
		if eval $compile && $run ./try > /dev/null; then
			dflt=`$run ./try`
			case "$dflt" in
			[1-4][1-4][1-4][1-4]|12345678|87654321)
				echo "(The test program ran ok.)"
				echo "byteorder=$dflt"
				xxx_prompt=n
			;;
			????|????????) echo "(The test program ran ok.)" ;;
			*) echo "(The test program didn't run right for some reason.)" ;;
			esac
		else
			dflt='4321'
			cat <<'EOM'
(I can't seem to compile the test program.  Guessing big-endian...)
EOM
		fi
		case "$xxx_prompt" in
		y)
			rp="What is the order of bytes in $uvtype?"
			. ./myread
			byteorder="$ans"
			;;
		*)	byteorder=$dflt
			;;
		esac
		;;
	esac
	$rm -f try.c try
	;;
esac