after  uintptr
	}
	var m uint64 = magic64
	magicptr := uintptr(m)
	x.before = magicptr
	x.after = magicptr
	var j unsafe.Pointer

	for _, p := range testPointers() {
		k := SwapPointer(&x.i, p)
		if x.i != p || k != j {
			t.Fatalf("p=%p i=%p j=%p k=%p", p, x.i, j, k)
		}
		j = p
	}
	if x.before != magicptr || x.after != magicptr {