return 0
		}
		// n > 0
		esize := s.Sizeof(t.elem)
		if esize < 0 {
			return -1 // element too large
		}
		if esize == 0 {
			return 0 // 0-size element
		}
		// esize > 0
		// Final size is esize * n; and size must be <= maxInt64.
		const maxInt64 = 1<<63 - 1
		if esize > maxInt64/n {
			return -1 // esize * n overflows
		}
		return esize * n
	case *Slice:
		return s.WordSize * 3

			return 0
		}
		// n > 0
		esize := s.Sizeof(t.elem)
		if esize < 0 {
			return -1 // element too large
		}
		if esize == 0 {
			return 0 // 0-size element
		}
		// esize > 0
		// Final size is esize * n; and size must be <= maxInt64.
		const maxInt64 = 1<<63 - 1
		if esize > maxInt64/n {
			return -1 // esize * n overflows
		}
		return esize * n
	case *Slice:
		return s.WordSize * 3

			return 0
		}
		// n > 0
		esize := s.Sizeof(t.elem)
		if esize < 0 {
			return -1 // element too large
		}
		if esize == 0 {
			return 0 // 0-size element
		}
		// esize > 0
		a := s.Alignof(t.elem)
		ea := align(esize, a) // possibly < 0 if align overflows
		if ea < 0 {
			return -1
		}
		// ea >= 1
		n1 := n - 1 // n1 >= 0
		// Final size is ea*n1 + esize; and size must be <= maxInt64.

			return 0
		}
		// n > 0
		esize := s.Sizeof(t.elem)
		if esize < 0 {
			return -1 // element too large
		}
		if esize == 0 {
			return 0 // 0-size element
		}
		// esize > 0
		a := s.Alignof(t.elem)
		ea := align(esize, a) // possibly < 0 if align overflows
		if ea < 0 {
			return -1
		}
		// ea >= 1
		n1 := n - 1 // n1 >= 0
		// Final size is ea*n1 + esize; and size must be <= maxInt64.

func quotToFloat32(a, b nat) (f float32, exact bool) {
	const (
		// float size in bits
		Fsize = 32

		// mantissa
		Msize  = 23
		Msize1 = Msize + 1 // incl. implicit 1
		Msize2 = Msize1 + 1

		// exponent
		Esize = Fsize - Msize1
		Ebias = 1<<(Esize-1) - 1
		Emin  = 1 - Ebias
		Emax  = Ebias
	)

	// TODO(adonovan): specialize common degenerate cases: 1.0, integers.

		return missing(fmt.Errorf("decoding output ID: %v", err))
	}
	i := 0
	for i < len(esize) && esize[i] == ' ' {
		i++
	}
	size, err := strconv.ParseInt(string(esize[i:]), 10, 64)
	if err != nil {
		return missing(fmt.Errorf("parsing size: %v", err))
	} else if size < 0 {
		return missing(errors.New("negative size"))
	}
	i = 0
	for i < len(etime) && etime[i] == ' ' {
		i++
	}

		if size == 0 {
			return H0 + Reg(Rd)
		} else if size == 1 {
			return S0 + Reg(Rd)
		} else if size == 2 {
			return D0 + Reg(Rd)
		} else {
			return nil
		}

	case arg_Vd_22_2__H_1__S_2:
		size := (x >> 22) & (1<<2 - 1)
		Rd := x & (1<<5 - 1)
		if size == 1 {
			return H0 + Reg(Rd)
		} else if size == 2 {
			return S0 + Reg(Rd)
		} else {
			return nil
		}

		r := int((p.Reg) & 31)

		Q := 0
		size := 0
		switch af {
		case ARNG_16B:
			Q = 1
			size = 0
		case ARNG_2D:
			Q = 1
			size = 3
		case ARNG_2S:
			Q = 0
			size = 2
		case ARNG_4H:
			Q = 0
			size = 1
		case ARNG_4S:
			Q = 1
			size = 2
		case ARNG_8B:
			Q = 0
			size = 0
		case ARNG_8H:
			Q = 1
			size = 1

		comparable = comparable && (ft.Equal != nil)

		offset := align(size, uintptr(ft.Align_))
		if offset < size {
			panic("reflect.StructOf: struct size would exceed virtual address space")
		}
		if ft.Align_ > typalign {
			typalign = ft.Align_
		}
		size = offset + ft.Size_
		if size < offset {
			panic("reflect.StructOf: struct size would exceed virtual address space")
		}
		f.Offset = offset

	"testing"
)

// randInt returns a pseudo-random Int in the range [1<<(size-1), (1<<size) - 1]
func randInt(r *rand.Rand, size uint) *Int {
	n := new(Int).Lsh(intOne, size-1)
	x := new(Int).Rand(r, n)
	return x.Add(x, n) // make sure result > 1<<(size-1)
}

func runGCD(b *testing.B, aSize, bSize uint) {
	if isRaceBuilder && (aSize > 1000 || bSize > 1000) {
		b.Skip("skipping on race builder")
	}