// but neither ptr nor end point into one themselves.

	return checkptrBase(ptr) != checkptrBase(end)
}

func checkptrArithmetic(p unsafe.Pointer, originals []unsafe.Pointer) {
	if 0 < uintptr(p) && uintptr(p) < minLegalPointer {
		throw("checkptr: pointer arithmetic computed bad pointer value")
	}

	// Check that if the computed pointer p points into a heap
	// object, then one of the original pointers must have pointed

	// buffer, or just track globally whether there are any
	// un-shaded stacks and flush after each stack scan.
	gcw := &pp.gcw
	pos := 0
	for _, ptr := range ptrs {
		if ptr < minLegalPointer {
			// nil pointers are very common, especially
			// for the "old" values. Filter out these and
			// other "obvious" non-heap pointers ASAP.
			//
			// TODO: Should we filter out nils in the fast

			nonNilValues[node.ptr.ID] = nil
			continue
		}
	}
}

// All platforms are guaranteed to fault if we load/store to anything smaller than this address.
//
// This should agree with minLegalPointer in the runtime.
const minZeroPage = 4096

// faultOnLoad is true if a load to an address below minZeroPage will trigger a SIGSEGV.
var faultOnLoad = buildcfg.GOOS != "aix"

	// collector scales well to 32 cpus.
	_MaxGcproc = 32

	// minLegalPointer is the smallest possible legal pointer.
	// This is the smallest possible architectural page size,
	// since we assume that the first page is never mapped.
	//
	// This should agree with minZeroPage in the compiler.
	minLegalPointer uintptr = 4096

	// minHeapForMetadataHugePages sets a threshold on when certain kinds of

		for b != 0 {
			j := uintptr(sys.TrailingZeros8(b))
			b &= b - 1
			pp := (*uintptr)(add(scanp, (i+j)*goarch.PtrSize))
		retry:
			p := *pp
			if f.valid() && 0 < p && p < minLegalPointer && debug.invalidptr != 0 {
				// Looks like a junk value in a pointer slot.
				// Live analysis wrong?
				getg().m.traceback = 2
				print("runtime: bad pointer in frame ", funcname(f), " at ", pp, ": ", hex(p), "\n")