diff --git a/ChangeLog b/ChangeLog
index db153f1..2f4dff1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2000-02-15  Andrew Cagney  <cagney@cygnus.com>
+
+	* config.guess: Rewrite NetBSD code.  Return *-*-netbsdelf* for
+	ELF systems and *-*-netbsd* for all others.  Provide a guideline
+	for how to match a NetBSD tupple.
+
 2000-02-15  Richard Henderson  <rth@cygnus.com>
 
 	* config.guess (alpha-osf, alpha-linux): Detect ev67.
diff --git a/config.guess b/config.guess
index 3049280..1ab5196 100755
--- a/config.guess
+++ b/config.guess
@@ -67,6 +67,43 @@ trap 'rm -f $dummy.c $dummy.o $dummy; exit 1' 1 2 15
 # Note: order is significant - the case branches are not exclusive.
 
 case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
+    *:NetBSD:*:*)
+	# Netbsd (nbsd) targets should (where applicable) match one or
+	# more of the tupples: *-*-netbsdelf*, *-*-netbsdaout*,
+	# *-*-netbsdecoff* and *-*-netbsd*.  For targets that recently
+	# switched to ELF, *-*-netbsd* would select select the old
+	# object file format.  This provides both forward
+	# compatibility and a consistent mechanism for selecting the
+	# object file format.
+	# Determine the machine/vendor (is the vendor relevant).
+	case "${UNAME_MACHINE}" in
+	    amiga) machine=m68k-cbm ;;
+	    arm32) machine=arm-unknown ;;
+	    atari*) machine=m68k-atari ;;
+	    sun3*) machine=m68k-sun ;;
+	    mac68k) machine=m68k-apple ;;
+	    macppc) machine=powerpc-apple ;;
+	    hp3[0-9][05]) machine=m68k-hp ;;
+	    ibmrt|romp-ibm) machine=romp-ibm ;;
+	    *) machine=${UNAME_MACHINE}-unknown ;;
+	esac
+	# The Operating System including object format.
+	if echo __ELF__ | $CC_FOR_BUILD -E - 2>/dev/null \
+		| grep __ELF__ >/dev/null
+	then
+	    # Once all utilities can be ECOFF (netbsdecoff) or a.out (netbsdaout).
+	    # Return netbsd for either.  FIX?
+	    os=netbsd
+	else
+	    os=netbsdelf
+	fi
+	# The OS release
+	release=`echo ${UNAME_RELEASE}|sed -e 's/[-_].*/\./'`
+	# Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
+	# contains redundant information, the shorter form:
+	# CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM is used.
+	echo "${machine}-${os}${release}"
+	exit 0 ;;
     alpha:OSF1:*:*)
 	if test $UNAME_RELEASE = "V4.0"; then
 		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
@@ -138,9 +175,6 @@ EOF
     Amiga*:UNIX_System_V:4.0:*)
 	echo m68k-cbm-sysv4
 	exit 0;;
-    amiga:NetBSD:*:*)
-      echo m68k-cbm-netbsd${UNAME_RELEASE}
-      exit 0 ;;
     amiga:OpenBSD:*:*)
 	echo m68k-unknown-openbsd${UNAME_RELEASE}
 	exit 0 ;;
@@ -171,9 +205,6 @@ EOF
     arm:RISC*:1.[012]*:*|arm:riscix:1.[012]*:*)
 	echo arm-acorn-riscix${UNAME_RELEASE}
 	exit 0;;
-    arm32:NetBSD:*:*)
-	echo arm-unknown-netbsd`echo ${UNAME_RELEASE}|sed -e 's/[-_].*/\./'`
-	exit 0 ;;
     SR2?01:HI-UX/MPP:*:*)
 	echo hppa1.1-hitachi-hiuxmpp
 	exit 0;;
@@ -230,9 +261,6 @@ EOF
     aushp:SunOS:*:*)
 	echo sparc-auspex-sunos${UNAME_RELEASE}
 	exit 0 ;;
-    atari*:NetBSD:*:*)
-	echo m68k-atari-netbsd${UNAME_RELEASE}
-	exit 0 ;;
     atari*:OpenBSD:*:*)
 	echo m68k-unknown-openbsd${UNAME_RELEASE}
 	exit 0 ;;
@@ -262,15 +290,9 @@ EOF
     *:*MiNT:*:* | *:*mint:*:* | *:*TOS:*:*)
         echo m68k-unknown-mint${UNAME_RELEASE}
         exit 0 ;;
-    sun3*:NetBSD:*:*)
-	echo m68k-sun-netbsd${UNAME_RELEASE}
-	exit 0 ;;
     sun3*:OpenBSD:*:*)
 	echo m68k-unknown-openbsd${UNAME_RELEASE}
 	exit 0 ;;
-    mac68k:NetBSD:*:*)
-	echo m68k-apple-netbsd${UNAME_RELEASE}
-	exit 0 ;;
     mac68k:OpenBSD:*:*)
 	echo m68k-unknown-openbsd${UNAME_RELEASE}
 	exit 0 ;;
@@ -283,9 +305,6 @@ EOF
     powerpc:machten:*:*)
 	echo powerpc-apple-machten${UNAME_RELEASE}
 	exit 0 ;;
-    macppc:NetBSD:*:*)
-        echo powerpc-apple-netbsd${UNAME_RELEASE}
-        exit 0 ;;
     RISC*:Mach:*:*)
 	echo mips-dec-mach_bsd4.3
 	exit 0 ;;
@@ -418,7 +437,7 @@ EOF
     ibmrt:4.4BSD:*|romp-ibm:BSD:*)
 	echo romp-ibm-bsd4.4
 	exit 0 ;;
-    ibmrt:*BSD:*|romp-ibm:BSD:*)            # covers RT/PC NetBSD and
+    ibmrt:*BSD:*|romp-ibm:BSD:*)            # covers RT/PC BSD and
 	echo romp-ibm-bsd${UNAME_RELEASE}   # 4.3 with uname added to
 	exit 0 ;;                           # report: romp-ibm BSD 4.3
     *:BOSX:*:*)
@@ -582,9 +601,6 @@ EOF
     F301:UNIX_System_V:*:*)
        echo f301-fujitsu-uxpv`echo $UNAME_RELEASE | sed 's/ .*//'`
        exit 0 ;;
-    hp3[0-9][05]:NetBSD:*:*)
-	echo m68k-hp-netbsd${UNAME_RELEASE}
-	exit 0 ;;
     hp300:OpenBSD:*:*)
 	echo m68k-unknown-openbsd${UNAME_RELEASE}
 	exit 0 ;;
@@ -606,9 +622,6 @@ EOF
 	fi
 	echo ${UNAME_MACHINE}-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`
 	exit 0 ;;
-    *:NetBSD:*:*)
-	echo ${UNAME_MACHINE}-unknown-netbsd`echo ${UNAME_RELEASE}|sed -e 's/[-_].*//'`
-	exit 0 ;;
     *:OpenBSD:*:*)
 	echo ${UNAME_MACHINE}-unknown-openbsd`echo ${UNAME_RELEASE}|sed -e 's/[-_].*/\./'`
 	exit 0 ;;