}

// alignDown rounds n down to a multiple of a. a must be a power of 2.
//
//go:nosplit
func alignDown(n, a uintptr) uintptr {
	return n &^ (a - 1)
}

// divRoundUp returns ceil(n / a).
func divRoundUp(n, a uintptr) uintptr {
	// a is generally a power of two. This will get inlined and
	// the compiler will optimize the division.
	return (n + a - 1) / a
}

	bytep, mask := (*gcBits)(p).bitp(n * 2)
	byteVal := atomic.Load8(bytep)
	return pinState{bytep, byteVal, mask}
}

func (s *mspan) pinnerBitSize() uintptr {
	return divRoundUp(uintptr(s.nelems)*2, 8)
}

// newPinnerBits returns a pointer to 8 byte aligned bytes to be used for this
// span's pinner bits. newPinnerBits is used to mark objects that are pinned.

		obj := uintptr(s.freeindex)
		if (*s.gcmarkBits.bytep(obj / 8)&^*s.allocBits.bytep(obj / 8))>>(obj%8) != 0 {
			s.reportZombies()
		}
		// Check remaining bytes.
		for i := obj/8 + 1; i < divRoundUp(uintptr(s.nelems), 8); i++ {
			if *s.gcmarkBits.bytep(i)&^*s.allocBits.bytep(i) != 0 {
				s.reportZombies()
			}
		}
	}

	// Count the number of free objects in this span.