BNE	negZeroOddInt		// y is an odd integer and y < 0
	BR	zeroNotOdd			// y is not an (odd) integer and y < 0

negZeroGtZero:
	// special case Pow(-0, y) = -0 for y an odd integer > 0
	// special case Pow(±0, y) = +0 for finite y > 0 and not an odd integer
	FIDBR	$5, F2, F4      //F2 translate to integer F4
	FCMPU	F2, F4
	BNE	zeroNotOddGtZero    // y is not an (odd) integer and y > 0
	FMOVD	$(2.0), F4

//
// To extend this to even integers, consider c = d0 * 2^k where d0 is odd.
// We can test whether x is divisible by both d0 and 2^k.
// For d0, the test is the same as above.  Let m be such that m*d0 mod 2^n == 1
// Then x*m mod 2^n <= ⎣(2^n - 1)/d0⎦ is the first test.
// The test for divisibility by 2^k is a check for k trailing zeroes.
// Note that since d0 is odd, m is odd and thus x*m will have the same number of

	{
		vcs:     "git",
		path:    "vcs-test.golang.org/git/odd-tags.git",
		rev:     "v0.1.0+build-metadata",
		version: "v0.1.1-0.20220223184835-9d863d525bbf",
		name:    "9d863d525bbfcc8eda09364738c4032393711a56",
		short:   "9d863d525bbf",
		time:    time.Date(2022, 2, 23, 18, 48, 35, 0, time.UTC),
	},
	{
		vcs:     "git",
		path:    "vcs-test.golang.org/git/odd-tags.git",
		rev:     "9d863d525bbf",

	extra := uint(-dexp2)
	extraMask := uint32(1<<extra - 1)

	di, dfrac := di>>extra, di&extraMask
	roundUp := false
	if exact {
		// If we computed an exact product, d + 1/2
		// should round to d+1 if 'd' is odd.
		roundUp = dfrac > 1<<(extra-1) ||
			(dfrac == 1<<(extra-1) && !d0) ||
			(dfrac == 1<<(extra-1) && d0 && di&1 == 1)
	} else {
		// otherwise, d+1/2 always rounds up because
		// we truncated below.

	}
}

// ModSqrt sets z to a square root of x mod p if such a square root exists, and
// returns z. The modulus p must be an odd prime. If x is not a square mod p,
// ModSqrt leaves z unchanged and returns nil. This function panics if p is
// not an odd integer, its behavior is undefined if p is odd but not prime.
func (z *Int) ModSqrt(x, p *Int) *Int {
	switch Jacobi(x, p) {
	case -1:
		return nil // x is not a square mod p

	// 386:"IMUL3L\t[$]678152731",-"ROLL",-"DIVQ"
	// arm64:"MOVD\t[$]-8737931403336103397","MUL",-"ROR",-"DIV"
	// arm:"MUL","CMP\t[$]226050910",-".*udiv"
	// ppc64x:"MULLD",-"ROTL"
	odd := n%19 == 0

	return even, odd
}

func Divisible(n int) (bool, bool) {
	// amd64:"IMULQ","ADD","ROLQ\t[$]63",-"DIVQ"
	// 386:"IMUL3L\t[$]-1431655765","ADDL\t[$]715827882","ROLL\t[$]31",-"DIVQ"

    int bTwos = Integer.numberOfTrailingZeros(b);
    b >>= bTwos; // divide out all 2s
    while (a != b) { // both a, b are odd
      // The key to the binary GCD algorithm is as follows:
      // Both a and b are odd. Assume a > b; then gcd(a - b, b) = gcd(a, b).
      // But in gcd(a - b, b), a - b is even and b is odd, so we can divide out powers of two.

      // We bend over backwards to avoid branching, adapting a technique from

    int bTwos = Integer.numberOfTrailingZeros(b);
    b >>= bTwos; // divide out all 2s
    while (a != b) { // both a, b are odd
      // The key to the binary GCD algorithm is as follows:
      // Both a and b are odd. Assume a > b; then gcd(a - b, b) = gcd(a, b).
      // But in gcd(a - b, b), a - b is even and b is odd, so we can divide out powers of two.

      // We bend over backwards to avoid branching, adapting a technique from

//
// Example:
//
// We want to calculate the sum (h) for a 64 byte message (m):
//
//   h = m[0:16]r⁴ + m[16:32]r³ + m[32:48]r² + m[48:64]r
//
// To do this we split the calculation into the even indices
// and odd indices of the message. These form our SIMD 'lanes':
//
//   h = m[ 0:16]r⁴ + m[32:48]r² +   <- lane 0
//       m[16:32]r³ + m[48:64]r      <- lane 1
//
// To calculate this iteratively we refactor so that both lanes

				// The characters at even offsets from the beginning of the
				// sequence are upper case; the ones at odd offsets are lower.
				// The correct mapping can be done by clearing or setting the low
				// bit in the sequence offset.
				// The constants UpperCase and TitleCase are even while LowerCase
				// is odd so we take the low bit from _case.
				return rune(cr.Lo) + ((r-rune(cr.Lo))&^1 | rune(_case&1)), true
			}