{"4.0", "2.0"},

		{"1p512", "1p256"},
		{"4p1024", "2p512"},
		{"9p2048", "3p1024"},

		{"1p-1024", "1p-512"},
		{"4p-2048", "2p-1024"},
		{"9p-4096", "3p-2048"},
	} {

	"errors"
	"sync"
)

// p256ElementLength is the length of an element of the base or scalar field,
// which have the same bytes length for all NIST P curves.
const p256ElementLength = 32

// P256Point is a P256 point. The zero value is NOT valid.
type P256Point struct {
	// The point is represented in projective coordinates (X:Y:Z),
	// where x = X/Z and y = Y/Z.
	x, y, z *fiat.P256Element
}

	})
	return _p224
}

var p256Once sync.Once
var _p256 *nistCurve[*nistec.P256Point]

func p256() *nistCurve[*nistec.P256Point] {
	p256Once.Do(func() {
		_p256 = &nistCurve[*nistec.P256Point]{
			newPoint: func() *nistec.P256Point { return nistec.NewP256Point() },
		}
		precomputeParams(_p256, elliptic.P256())
	})
	return _p256
}

var p384Once sync.Once
var _p384 *nistCurve[*nistec.P384Point]

Filippo Valsorda <******@****.***> 1650474738 -0400

//go:build (amd64 || arm64) && !purego

package nistec_test

import (
	"bytes"
	"crypto/elliptic"
	"crypto/internal/nistec"
	"math/big"
	"testing"
)

func TestP256OrdInverse(t *testing.T) {
	N := elliptic.P256().Params().N

	// inv(0) is expected to be 0.
	zero := make([]byte, 32)
	out, err := nistec.P256OrdInverse(zero)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(out, zero) {

Filippo Valsorda <******@****.***> 1684936196 +0200

DATA p256ord<>+0x18(SB)/8, $0xf3b9cac2fc632551
DATA p256<>+0x00(SB)/8, $0xffffffff00000001 // P256
DATA p256<>+0x08(SB)/8, $0x0000000000000000 // P256
DATA p256<>+0x10(SB)/8, $0x00000000ffffffff // P256
DATA p256<>+0x18(SB)/8, $0xffffffffffffffff // P256
DATA p256<>+0x20(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x28(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x30(SB)/8, $0x0000000010111213 // SEL 0  d1 d0  0

Filippo Valsorda <******@****.***> 1684886145 +0200

	}

	p256, ok := P256().(combinedMult)
	if !ok {
		p256 = &synthCombinedMult{P256()}
	}

	gx := p256.Params().Gx
	gy := p256.Params().Gy

	zero := make([]byte, 32)
	one := make([]byte, 32)
	one[31] = 1
	two := make([]byte, 32)
	two[31] = 2

	// 0×G + 0×G = ∞
	x, y := p256.CombinedMult(gx, gy, zero, zero)
	if x.Sign() != 0 || y.Sign() != 0 {

// on little endian.
DATA p256<>+0x00(SB)/8, $0xffffffff00000001 // P256
DATA p256<>+0x08(SB)/8, $0x0000000000000000 // P256
DATA p256<>+0x10(SB)/8, $0x00000000ffffffff // P256
DATA p256<>+0x18(SB)/8, $0xffffffffffffffff // P256
DATA p256<>+0x20(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x28(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x30(SB)/8, $0x0000000010111213 // SEL 0  d1 d0  0