func extractDigit() int64 {
	if big.CmpInt(numer, accum) > 0 {
		return -1
	}
	tmp1.Lsh(numer, 1).Add(tmp1, numer).Add(tmp1, accum)
	big.DivModInt(tmp1, tmp2, tmp1, denom)
	tmp2.Add(tmp2, numer)
	if big.CmpInt(tmp2, denom) >= 0 {
		return -1
	}
	return tmp1.Int64()
}

func nextTerm(k int64) {
	y2 := k*2 + 1
	accum.Add(accum, tmp1.Lsh(numer, 1))
	accum.Mul(accum, tmp1.SetInt64(y2))
	numer.Mul(numer, tmp1.SetInt64(k))

// returned by text/scanner.Scanner, plus a couple of extra values.
type ScanToken rune

const (
	// Asm defines some two-character lexemes. We make up
	// a rune/ScanToken value for them - ugly but simple.
	LSH          ScanToken = -1000 - iota // << Left shift.
	RSH                                   // >> Logical right shift.
	ARR                                   // -> Used on ARM for shift type 3, arithmetic right shift.

	ext := ""
	if p.peek() == lex.LSH {
		// (Rn)(Rm<<2), the shifted offset register.
		ext = "LSL"
	} else {
		// (Rn)(Rm.UXTW<1), the extended offset register.
		// Rm.UXTW<<3, the extended register.
		p.get('.')
		tok := p.next()
		ext = tok.String()
	}
	if p.peek() == lex.LSH {
		// parses left shift amount applied after extension: <<Amount
		p.get(lex.LSH)
		tok := p.get(scanner.Int)

	if err != nil {
		return nil, nil, fmt.Errorf("failed to generate private key: %w", err)
	}

	notBefore := time.Now()
	notAfter := notBefore.Add(validFor)

	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
	serialNumber, err := crand.Int(crand.Reader, serialNumberLimit)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to generate serial number: %w", err)
	}

	template := x509.Certificate{

*   Fixes an undefined behavior arising from null pointer dereference in TFLite
    MLIR optimizations
    ([CVE-2021-37689](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-37689))
*   Fixes a FPE in LSH in TFLite
    ([CVE-2021-37691](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-37691))
*   Fixes a segfault on strings tensors with mismatched dimensions, arising in
    Go code