if c.instoffset >= 0 {
			sbits := bits.Len64(uint64(c.instoffset))
			switch {
			case sbits <= 5:
				return C_ZCON + sbits
			case sbits <= 8:
				return C_U8CON
			case sbits <= 15:
				return C_U15CON
			case sbits <= 16:
				return C_U16CON
			case sbits <= 31:
				return C_U31CON
			case sbits <= 32:
				return C_U32CON
			case sbits <= 33:
				return C_S34CON

	}

	switch x.form {
	case finite:
		// 0 < |x| < +Inf

		const (
			fbits = 32                //        float size
			mbits = 23                //        mantissa size (excluding implicit msb)
			ebits = fbits - mbits - 1 //     8  exponent size
			bias  = 1<<(ebits-1) - 1  //   127  exponent bias
			dmin  = 1 - bias - mbits  //  -149  smallest unbiased exponent (denormal)

func bitSetTest(x int) bool {
	// amd64:"ANDL\t[$]9, AX"
	// amd64:"CMPQ\tAX, [$]9"
	return x&9 == 9
}

// mask contiguous one bits
func cont1Mask64U(x uint64) uint64 {
	// s390x:"RISBGZ\t[$]16, [$]47, [$]0,"
	return x & 0x0000ffffffff0000
}

// mask contiguous zero bits
func cont0Mask64U(x uint64) uint64 {
	// s390x:"RISBGZ\t[$]48, [$]15, [$]0,"
	return x & 0xffff00000000ffff
}

	if traceAllocFreeEnabled() || debug.clobberfree != 0 || raceenabled || msanenabled || asanenabled {
		// Find all newly freed objects.
		mbits := s.markBitsForBase()
		abits := s.allocBitsForIndex(0)
		for i := uintptr(0); i < uintptr(s.nelems); i++ {
			if !mbits.isMarked() && (abits.index < uintptr(s.freeindex) || abits.isMarked()) {
				x := s.base() + i*s.elemsize
				if traceAllocFreeEnabled() {
					trace := traceAcquire()

// addition/subtraction of arguments represented by Bits values with the
// respective Float addition/subtraction for a variety of precisions
// and rounding modes.
func TestFloatAdd(t *testing.T) {
	for _, xbits := range bitsList {
		for _, ybits := range bitsList {
			// exact values
			x := xbits.Float()
			y := ybits.Float()
			zbits := xbits.add(ybits)
			z := zbits.Float()

			for ; c >= npattern; c -= npattern {
				bits |= pattern << nbits
				nbits += npattern
				for nbits >= 8 {
					*dst = uint8(bits)
					dst = add1(dst)
					bits >>= 8
					nbits -= 8
				}
			}

			// Add final fragment to bit buffer.
			if c > 0 {
				pattern &= 1<<c - 1
				bits |= pattern << nbits
				nbits += c
			}
			continue Run
		}

}

// writeLSB writes the code c for "Least Significant Bits first" data.
func (w *Writer) writeLSB(c uint32) error {
	w.bits |= c << w.nBits
	w.nBits += w.width
	for w.nBits >= 8 {
		if err := w.w.WriteByte(uint8(w.bits)); err != nil {
			return err
		}
		w.bits >>= 8
		w.nBits -= 8
	}
	return nil
}

// writeMSB writes the code c for "Most Significant Bits first" data.
func (w *Writer) writeMSB(c uint32) error {

	var p Bits
	for _, x := range x {
		for _, y := range y {
			p = append(p, x+y)
		}
	}
	return p
}

func TestMulBits(t *testing.T) {
	for _, test := range []struct {
		x, y, want Bits
	}{
		{nil, nil, nil},
		{Bits{}, Bits{}, nil},
		{Bits{0}, Bits{0}, Bits{0}},
		{Bits{0}, Bits{1}, Bits{1}},
		{Bits{1}, Bits{1, 2, 3}, Bits{2, 3, 4}},
		{Bits{-1}, Bits{1}, Bits{0}},

		{11, 2048 - 1024},
		{12, 4096 - 2048},
	}
	nCodes, nBits := 0, 0
	for _, e := range iterations {
		nCodes += e.n
		nBits += e.n * e.width
	}
	if nCodes != 3839 {
		t.Fatalf("nCodes: got %v, want %v", nCodes, 3839)
	}
	if nBits != 43255 {
		t.Fatalf("nBits: got %v, want %v", nBits, 43255)
	}

	// Construct our input of 43255 zero bits (which gets d.hi and d.width up

}

// setCheckmark throws if marking object is a checkmarks violation,
// and otherwise sets obj's checkmark. It returns true if obj was
// already checkmarked.
func setCheckmark(obj, base, off uintptr, mbits markBits) bool {
	if !mbits.isMarked() {
		printlock()
		print("runtime: checkmarks found unexpected unmarked object obj=", hex(obj), "\n")
		print("runtime: found obj at *(", hex(base), "+", hex(off), ")\n")