package big_test

import (
	"fmt"
	"math"
	"math/big"
)

func ExampleFloat_Add() {
	// Operate on numbers of different precision.
	var x, y, z big.Float
	x.SetInt64(1000)          // x is automatically set to 64bit precision
	y.SetFloat64(2.718281828) // y is automatically set to 53bit precision
	z.SetPrec(32)
	z.Add(&x, &y)

	}

	// Bits 0:51 (bytes 0:8, bits 0:64, shift 0, mask 51).
	v.l0 = byteorder.LeUint64(x[0:8])
	v.l0 &= maskLow51Bits
	// Bits 51:102 (bytes 6:14, bits 48:112, shift 3, mask 51).
	v.l1 = byteorder.LeUint64(x[6:14]) >> 3
	v.l1 &= maskLow51Bits
	// Bits 102:153 (bytes 12:20, bits 96:160, shift 6, mask 51).
	v.l2 = byteorder.LeUint64(x[12:20]) >> 6
	v.l2 &= maskLow51Bits

func euclidExtGCD(a, b *Int) (g, x, y *Int) {
	A := new(Int).Set(a)
	B := new(Int).Set(b)

	// A = Ua*a + Va*b
	// B = Ub*a + Vb*b
	Ua := new(Int).SetInt64(1)
	Va := new(Int)

	Ub := new(Int)
	Vb := new(Int).SetInt64(1)

	q := new(Int)
	temp := new(Int)

	r := new(Int)
	for len(B.abs) > 0 {
		q, r = q.QuoRem(A, B, r)

		A, B, r = B, r, A

		// Ua, Ub = Ub, Ua-q*Ub

	}
}

func TestIssue6866(t *testing.T) {
	for _, prec := range precList {
		two := new(Float).SetPrec(prec).SetInt64(2)
		one := new(Float).SetPrec(prec).SetInt64(1)
		three := new(Float).SetPrec(prec).SetInt64(3)
		msix := new(Float).SetPrec(prec).SetInt64(-6)
		psix := new(Float).SetPrec(prec).SetInt64(+6)

		p := new(Float).SetPrec(prec)
		z1 := new(Float).SetPrec(prec)
		z2 := new(Float).SetPrec(prec)

	// changes must be reviewed by a security expert.
	if len(x.abs) == 0 {
		return 0
	}
	if x.neg {
		return -1
	}
	return 1
}

// SetInt64 sets z to x and returns z.
func (z *Int) SetInt64(x int64) *Int {
	neg := false
	if x < 0 {
		neg = true
		x = -x
	}
	z.abs = z.abs.setUint64(uint64(x))
	z.neg = neg
	return z
}

// SetUint64 sets z to x and returns z.

		bufA[i], bufB[i] = a[len(a)-i-1], b[len(b)-i-1]
	}

	// Perform a subtraction with borrow.
	var borrow uint64
	for i := 0; i < len(bufA); i += 8 {
		limbA, limbB := byteorder.LeUint64(bufA[i:]), byteorder.LeUint64(bufB[i:])
		_, borrow = bits.Sub64(limbA, limbB, borrow)
	}

	// If there is a borrow at the end of the operation, then a < b.
	return borrow == 1
}

	if b == 0 {
		panic("division by zero")
	}
	z.a.SetInt64(a)
	if b < 0 {
		b = -b
		z.a.neg = !z.a.neg
	}
	z.b.abs = z.b.abs.setUint64(uint64(b))
	return z.norm()
}

// SetInt sets z to x (by making a copy of x) and returns z.
func (z *Rat) SetInt(x *Int) *Rat {
	z.a.Set(x)
	z.b.abs = z.b.abs.setWord(1)
	return z
}

// SetInt64 sets z to x and returns z.

		return errors.New("crypto/dsa: invalid ParameterSizes")
	}

	qBytes := make([]byte, N/8)
	pBytes := make([]byte, L/8)

	q := new(big.Int)
	p := new(big.Int)
	rem := new(big.Int)
	one := new(big.Int)
	one.SetInt64(1)

GeneratePrimes:
	for {
		if _, err := io.ReadFull(rand, qBytes); err != nil {
			return err
		}

		qBytes[len(qBytes)-1] |= 1
		qBytes[0] |= 0x80
		q.SetBytes(qBytes)

	ConstPrec = 512
)

func BigFloat(v constant.Value) *big.Float {
	f := new(big.Float)
	f.SetPrec(ConstPrec)
	switch u := constant.Val(v).(type) {
	case int64:
		f.SetInt64(u)
	case *big.Int:
		f.SetInt(u)
	case *big.Float:
		f.Set(u)
	case *big.Rat:
		f.SetRat(u)
	default:
		base.Fatalf("unexpected: %v", u)
	}
	return f
}

// 0) is not on the any of the curves handled here.
func zForAffine(x, y *big.Int) *big.Int {
	z := new(big.Int)
	if x.Sign() != 0 || y.Sign() != 0 {
		z.SetInt64(1)
	}
	return z
}

// affineFromJacobian reverses the Jacobian transform. See the comment at the
// top of the file. If the point is ∞ it returns 0, 0.