diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 61470bb5add..5382a0672c5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2005-12-29  Paul Brook  <paul@codesourcery.com>
+
+	* config/m68k/fpgnulib.c (__extendsfdf2): Handle negative zero.
+	(__truncdfsf2): Ditto.
+	(__extenddfxf2): Ditto.
+	(__truncxfdf2): Ditto.
+	* config/m68k/lb1sf68.asm (__addsf3): Return -0.0 for -0.0 + -0.0.
+	(__adddf3): Ditto.
+
 2005-12-29  Daniel Jacobowitz  <dan@codesourcery.com>
 	Paul Brook  <paul@codesourcery.com>
 
diff --git a/gcc/config/m68k/fpgnulib.c b/gcc/config/m68k/fpgnulib.c
index a3ebc21608e..1ef43c758f0 100644
--- a/gcc/config/m68k/fpgnulib.c
+++ b/gcc/config/m68k/fpgnulib.c
@@ -241,13 +241,13 @@ __extendsfdf2 (float a1)
 
   fl1.f = a1;
 
-  if (!fl1.l)
+  dl.l.upper = SIGN (fl1.l);
+  if ((fl1.l & ~SIGNBIT) == 0)
     {
-      dl.l.upper = dl.l.lower = 0;
+      dl.l.lower = 0;
       return dl.d;
     }
 
-  dl.l.upper = SIGN (fl1.l);
   exp = EXP(fl1.l);
   mant = MANT (fl1.l) & ~HIDDEN;
   if (exp == 0)
@@ -280,8 +280,11 @@ __truncdfsf2 (double a1)
 
   dl1.d = a1;
 
-  if (!dl1.l.upper && !dl1.l.lower)
-    return 0;
+  if ((dl1.l.upper & ~SIGNBIT) == 0 && !dl1.l.lower)
+    {
+      fl.l = SIGND(dl1);
+      return fl.f;
+    }
 
   exp = EXPD (dl1) - EXCESSD + EXCESS;
 
@@ -398,10 +401,14 @@ __extenddfxf2 (double d)
   dl.d = d;
   /*printf ("dfxf in: %g\n", d);*/
 
-  if (!dl.l.upper && !dl.l.lower)
-    return 0;
-
   ldl.l.upper = SIGND (dl);
+  if ((dl.l.upper & ~SIGNBIT) == 0 && !dl.l.lower)
+    {
+      ldl.l.middle = 0;
+      ldl.l.lower = 0;
+      return ldl.ld;
+    }
+
   exp = EXPD (dl) - EXCESSD + EXCESSX;
   ldl.l.upper |= exp << 16;
   ldl.l.middle = HIDDENX;
@@ -427,14 +434,17 @@ __truncxfdf2 (long double ld)
   ldl.ld = ld;
   /*printf ("xfdf in: %s\n", dumpxf (ld));*/
 
-  if (!ldl.l.upper && !ldl.l.middle && !ldl.l.lower)
-    return 0;
+  dl.l.upper = SIGNX (ldl);
+  if ((ldl.l.upper & ~SIGNBIT) == 0 && !ldl.l.middle && !ldl.l.lower)
+    {
+      dl.l.lower = 0;
+      return dl.d;
+    }
 
   exp = EXPX (ldl) - EXCESSX + EXCESSD;
   /* ??? quick and dirty: keep `exp' sane */
   if (exp >= EXPDMASK)
     exp = EXPDMASK - 1;
-  dl.l.upper = SIGNX (ldl);
   dl.l.upper |= exp << (32 - (EXPDBITS + 1));
   /* +1-1: add one for sign bit, but take one off for explicit-integer-bit */
   dl.l.upper |= (ldl.l.middle & MANTXMASK) >> (EXPDBITS + 1 - 1);
diff --git a/gcc/config/m68k/lb1sf68.asm b/gcc/config/m68k/lb1sf68.asm
index e1b4c2fcc3d..2e239b33387 100644
--- a/gcc/config/m68k/lb1sf68.asm
+++ b/gcc/config/m68k/lb1sf68.asm
@@ -1285,7 +1285,12 @@ Ladddf$b:
 | Return b (if a is zero)
 	movel	d2,d0
 	movel	d3,d1
-	bra	1f
+	bne	1f			| Check if b is -0
+	cmpl	IMM (0x80000000),d0
+	bne	1f
+	andl	IMM (0x80000000),d7	| Use the sign of a
+	clrl	d0
+	bra	Ladddf$ret
 Ladddf$a:
 	movel	a6@(8),d0
 	movel	a6@(12),d1
@@ -2570,16 +2575,13 @@ SYM (__addsf3):
 #endif
 	movel	a6@(8),d0	| get first operand
 	movel	a6@(12),d1	| get second operand
-	movel	d0,d6		| get d0's sign bit '
+	movel	d0,a0		| get d0's sign bit '
 	addl	d0,d0		| check and clear sign bit of a
 	beq	Laddsf$b	| if zero return second operand
-	movel	d1,d7		| save b's sign bit '
+	movel	d1,a1		| save b's sign bit '
 	addl	d1,d1		| get rid of sign bit
 	beq	Laddsf$a	| if zero return first operand
 
-	movel	d6,a0		| save signs in address registers
-	movel	d7,a1		| so we can use d6 and d7
-
 | Get the exponents and check for denormalized and/or infinity.
 
 	movel	IMM (0x00ffffff),d4	| mask to get fraction
@@ -2950,7 +2952,12 @@ Laddsf$b$den:
 Laddsf$b:
 | Return b (if a is zero).
 	movel	a6@(12),d0
-	bra	1f
+	cmpl	IMM (0x80000000),d0	| Check if b is -0
+	bne	1f
+	movel	a0,d7
+	andl	IMM (0x80000000),d7	| Use the sign of a
+	clrl	d0
+	bra	Laddsf$ret
 Laddsf$a:
 | Return a (if b is zero).
 	movel	a6@(8),d0