if w.err != nil {
		return
	}
	w.bits |= uint64(b) << w.nbits
	w.nbits += nb
	if w.nbits >= 48 {
		bits := w.bits
		w.bits >>= 48
		w.nbits -= 48
		n := w.nbytes
		bytes := w.bytes[n : n+6]
		bytes[0] = byte(bits)
		bytes[1] = byte(bits >> 8)
		bytes[2] = byte(bits >> 16)
		bytes[3] = byte(bits >> 24)
		bytes[4] = byte(bits >> 32)
		bytes[5] = byte(bits >> 40)
		n += 6
		if n >= bufferFlushSize {

	// table with the first 10 bits from the mantissa.
	xExp := int64((xBits>>52)&0x7FF) - 1023
	xManIndex := (xBits >> (52 - fastlogNumBits)) % (1 << fastlogNumBits)
	xManScale := (xBits >> (52 - fastlogNumBits - fastlogScaleBits)) % (1 << fastlogScaleBits)

	low, high := fastlog2Table[xManIndex], fastlog2Table[xManIndex+1]
	return float64(xExp) + low + (high-low)*float64(xManScale)*fastlogScaleRatio

}

// 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 {

}

// readLSB returns the next code for "Least Significant Bits first" data.
func (r *Reader) readLSB() (uint16, error) {
	for r.nBits < r.width {
		x, err := r.r.ReadByte()
		if err != nil {
			return 0, err
		}
		r.bits |= uint32(x) << r.nBits
		r.nBits += 8
	}
	code := uint16(r.bits & (1<<r.width - 1))
	r.bits >>= r.width
	r.nBits -= r.width
	return code, nil
}

	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()

		{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

// bytes, and throws if it finds an unpinned Go pointer. The gcbits mark each
// pointer value. The src pointer is off bytes into the gcbits.
//
//go:nosplit
//go:nowritebarrier
func cgoCheckBits(src unsafe.Pointer, gcbits *byte, off, size uintptr) {
	skipMask := off / goarch.PtrSize / 8
	skipBytes := skipMask * goarch.PtrSize * 8
	ptrmask := addb(gcbits, skipMask)
	src = add(src, skipBytes)
	off -= skipBytes

	var vectors = []struct {
		nbits uint // Number of bits to read
		value int  // Expected output value (0 for error)
		fail  bool // Expected operation failure?
	}{
		{nbits: 1, value: 1},
		{nbits: 1, value: 0},
		{nbits: 1, value: 1},
		{nbits: 5, value: 11},
		{nbits: 32, value: 0x12345678},
		{nbits: 15, value: 14495},
		{nbits: 3, value: 6},
		{nbits: 6, value: 13},
		{nbits: 1, fail: true},
	}

}

// 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")

				nbits -= shift
			}

			// convert any partial leading digit and advance to next word
			if nbits == 0 {
				// no partial digit remaining, just advance
				w = x[k]
				nbits = _W
			} else {
				// partial digit in current word w (== x[k-1]) and next word x[k]
				w |= x[k] << nbits
				i--
				s[i] = digits[w&mask]

				// advance
				w = x[k] >> (shift - nbits)