mirror of
https://github.com/emmansun/gmsm.git
synced 2025-04-25 19:56:18 +08:00
602 lines
20 KiB
Go
602 lines
20 KiB
Go
// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build ignore
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package main
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// Running this generator requires addchain v0.4.0, which can be installed with
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//
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// go install github.com/mmcloughlin/addchain/cmd/addchain@v0.4.0
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//
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import (
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"bytes"
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"crypto/elliptic"
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"fmt"
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"go/format"
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"io"
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"log"
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"math/big"
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"os"
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"os/exec"
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"strings"
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"text/template"
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_sm2ec "github.com/emmansun/gmsm/sm2/sm2ec"
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)
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var curves = []struct {
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P string
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Element string
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Params *elliptic.CurveParams
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BuildTags string
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}{
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{
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P: "SM2P256",
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Element: "fiat.SM2P256Element",
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Params: _sm2ec.P256().Params(),
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BuildTags: "",
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},
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}
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func main() {
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t := template.Must(template.New("tmplNISTEC").Parse(tmplNISTEC))
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tmplAddchainFile, err := os.CreateTemp("", "addchain-template")
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if err != nil {
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log.Fatal(err)
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}
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defer os.Remove(tmplAddchainFile.Name())
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if _, err := io.WriteString(tmplAddchainFile, tmplAddchain); err != nil {
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log.Fatal(err)
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}
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if err := tmplAddchainFile.Close(); err != nil {
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log.Fatal(err)
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}
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for _, c := range curves {
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p := strings.ToLower(c.P)
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elementLen := (c.Params.BitSize + 7) / 8
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B := fmt.Sprintf("%#v", c.Params.B.FillBytes(make([]byte, elementLen)))
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Gx := fmt.Sprintf("%#v", c.Params.Gx.FillBytes(make([]byte, elementLen)))
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Gy := fmt.Sprintf("%#v", c.Params.Gy.FillBytes(make([]byte, elementLen)))
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log.Printf("Generating %s.go...", p)
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f, err := os.Create(p + ".go")
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if err != nil {
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log.Fatal(err)
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}
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defer f.Close()
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buf := &bytes.Buffer{}
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if err := t.Execute(buf, map[string]any{
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"P": c.P, "p": p, "B": B, "Gx": Gx, "Gy": Gy,
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"Element": c.Element, "ElementLen": elementLen,
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"BuildTags": c.BuildTags,
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}); err != nil {
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log.Fatal(err)
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}
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out, err := format.Source(buf.Bytes())
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if err != nil {
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log.Fatal(err)
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}
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if _, err := f.Write(out); err != nil {
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log.Fatal(err)
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}
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// If p = 3 mod 4, implement modular square root by exponentiation.
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mod4 := new(big.Int).Mod(c.Params.P, big.NewInt(4))
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if mod4.Cmp(big.NewInt(3)) != 0 {
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continue
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}
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exp := new(big.Int).Add(c.Params.P, big.NewInt(1))
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exp.Div(exp, big.NewInt(4))
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tmp, err := os.CreateTemp("", "addchain-"+p)
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if err != nil {
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log.Fatal(err)
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}
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defer os.Remove(tmp.Name())
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cmd := exec.Command("addchain", "search", fmt.Sprintf("%d", exp))
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cmd.Stderr = os.Stderr
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cmd.Stdout = tmp
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if err := cmd.Run(); err != nil {
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log.Fatal(err)
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}
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if err := tmp.Close(); err != nil {
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log.Fatal(err)
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}
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cmd = exec.Command("addchain", "gen", "-tmpl", tmplAddchainFile.Name(), tmp.Name())
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cmd.Stderr = os.Stderr
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out, err = cmd.Output()
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if err != nil {
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log.Fatal(err)
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}
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out = bytes.Replace(out, []byte("Element"), []byte(c.Element), -1)
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out = bytes.Replace(out, []byte("sqrtCandidate"), []byte(p+"SqrtCandidate"), -1)
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out, err = format.Source(out)
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if err != nil {
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log.Fatal(err)
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}
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if _, err := f.Write(out); err != nil {
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log.Fatal(err)
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}
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}
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}
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const tmplNISTEC = `// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Code generated by generate.go. DO NOT EDIT.
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{{ if .BuildTags }}
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//go:build {{ .BuildTags }}
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{{ end }}
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package sm2ec
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import (
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"github.com/emmansun/gmsm/internal/sm2ec/fiat"
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"crypto/subtle"
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"errors"
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"sync"
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)
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// {{.p}}ElementLength is the length of an element of the base or scalar field,
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// which have the same bytes length for all NIST P curves.
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const {{.p}}ElementLength = {{ .ElementLen }}
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// {{.P}}Point is a {{.P}} point. The zero value is NOT valid.
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type {{.P}}Point struct {
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// The point is represented in projective coordinates (X:Y:Z),
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// where x = X/Z and y = Y/Z.
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x, y, z *{{.Element}}
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}
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// New{{.P}}Point returns a new {{.P}}Point representing the point at infinity point.
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func New{{.P}}Point() *{{.P}}Point {
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return &{{.P}}Point{
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x: new({{.Element}}),
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y: new({{.Element}}).One(),
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z: new({{.Element}}),
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}
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}
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// SetGenerator sets p to the canonical generator and returns p.
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func (p *{{.P}}Point) SetGenerator() *{{.P}}Point {
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p.x.SetBytes({{.Gx}})
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p.y.SetBytes({{.Gy}})
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p.z.One()
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return p
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}
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// Set sets p = q and returns p.
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func (p *{{.P}}Point) Set(q *{{.P}}Point) *{{.P}}Point {
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p.x.Set(q.x)
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p.y.Set(q.y)
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p.z.Set(q.z)
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return p
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}
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// SetBytes sets p to the compressed, uncompressed, or infinity value encoded in
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// b, as specified in SEC 1, Version 2.0, Section 2.3.4. If the point is not on
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// the curve, it returns nil and an error, and the receiver is unchanged.
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// Otherwise, it returns p.
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func (p *{{.P}}Point) SetBytes(b []byte) (*{{.P}}Point, error) {
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switch {
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// Point at infinity.
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case len(b) == 1 && b[0] == 0:
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return p.Set(New{{.P}}Point()), nil
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// Uncompressed form.
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case len(b) == 1+2*{{.p}}ElementLength && b[0] == 4:
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x, err := new({{.Element}}).SetBytes(b[1 : 1+{{.p}}ElementLength])
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if err != nil {
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return nil, err
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}
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y, err := new({{.Element}}).SetBytes(b[1+{{.p}}ElementLength:])
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if err != nil {
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return nil, err
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}
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if err := {{.p}}CheckOnCurve(x, y); err != nil {
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return nil, err
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}
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p.x.Set(x)
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p.y.Set(y)
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p.z.One()
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return p, nil
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// Compressed form.
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case len(b) == 1+{{.p}}ElementLength && (b[0] == 2 || b[0] == 3):
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x, err := new({{.Element}}).SetBytes(b[1:])
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if err != nil {
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return nil, err
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}
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// y² = x³ - 3x + b
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y := {{.p}}Polynomial(new({{.Element}}), x)
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if !{{.p}}Sqrt(y, y) {
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return nil, errors.New("invalid {{.P}} compressed point encoding")
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}
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// Select the positive or negative root, as indicated by the least
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// significant bit, based on the encoding type byte.
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otherRoot := new({{.Element}})
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otherRoot.Sub(otherRoot, y)
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cond := y.Bytes()[{{.p}}ElementLength-1]&1 ^ b[0]&1
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y.Select(otherRoot, y, int(cond))
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p.x.Set(x)
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p.y.Set(y)
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p.z.One()
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return p, nil
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default:
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return nil, errors.New("invalid {{.P}} point encoding")
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}
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}
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var _{{.p}}B *{{.Element}}
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var _{{.p}}BOnce sync.Once
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func {{.p}}B() *{{.Element}} {
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_{{.p}}BOnce.Do(func() {
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_{{.p}}B, _ = new({{.Element}}).SetBytes({{.B}})
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})
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return _{{.p}}B
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}
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// {{.p}}Polynomial sets y2 to x³ - 3x + b, and returns y2.
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func {{.p}}Polynomial(y2, x *{{.Element}}) *{{.Element}} {
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y2.Square(x)
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y2.Mul(y2, x)
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threeX := new({{.Element}}).Add(x, x)
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threeX.Add(threeX, x)
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y2.Sub(y2, threeX)
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return y2.Add(y2, {{.p}}B())
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}
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func {{.p}}CheckOnCurve(x, y *{{.Element}}) error {
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// y² = x³ - 3x + b
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rhs := {{.p}}Polynomial(new({{.Element}}), x)
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lhs := new({{.Element}}).Square(y)
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if rhs.Equal(lhs) != 1 {
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return errors.New("{{.P}} point not on curve")
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}
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return nil
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}
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// Bytes returns the uncompressed or infinity encoding of p, as specified in
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// SEC 1, Version 2.0, Section 2.3.3. Note that the encoding of the point at
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// infinity is shorter than all other encodings.
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func (p *{{.P}}Point) Bytes() []byte {
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// This function is outlined to make the allocations inline in the caller
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// rather than happen on the heap.
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var out [1+2*{{.p}}ElementLength]byte
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return p.bytes(&out)
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}
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func (p *{{.P}}Point) bytes(out *[1+2*{{.p}}ElementLength]byte) []byte {
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if p.z.IsZero() == 1 {
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return append(out[:0], 0)
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}
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zinv := new({{.Element}}).Invert(p.z)
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x := new({{.Element}}).Mul(p.x, zinv)
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y := new({{.Element}}).Mul(p.y, zinv)
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buf := append(out[:0], 4)
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buf = append(buf, x.Bytes()...)
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buf = append(buf, y.Bytes()...)
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return buf
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}
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// BytesX returns the encoding of the x-coordinate of p, as specified in SEC 1,
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// Version 2.0, Section 2.3.5, or an error if p is the point at infinity.
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func (p *{{.P}}Point) BytesX() ([]byte, error) {
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// This function is outlined to make the allocations inline in the caller
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// rather than happen on the heap.
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var out [{{.p}}ElementLength]byte
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return p.bytesX(&out)
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}
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func (p *{{.P}}Point) bytesX(out *[{{.p}}ElementLength]byte) ([]byte, error) {
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if p.z.IsZero() == 1 {
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return nil, errors.New("{{.P}} point is the point at infinity")
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}
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zinv := new({{.Element}}).Invert(p.z)
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x := new({{.Element}}).Mul(p.x, zinv)
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return append(out[:0], x.Bytes()...), nil
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}
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// BytesCompressed returns the compressed or infinity encoding of p, as
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// specified in SEC 1, Version 2.0, Section 2.3.3. Note that the encoding of the
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// point at infinity is shorter than all other encodings.
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func (p *{{.P}}Point) BytesCompressed() []byte {
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// This function is outlined to make the allocations inline in the caller
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// rather than happen on the heap.
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var out [1 + {{.p}}ElementLength]byte
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return p.bytesCompressed(&out)
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}
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func (p *{{.P}}Point) bytesCompressed(out *[1 + {{.p}}ElementLength]byte) []byte {
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if p.z.IsZero() == 1 {
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return append(out[:0], 0)
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}
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zinv := new({{.Element}}).Invert(p.z)
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x := new({{.Element}}).Mul(p.x, zinv)
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y := new({{.Element}}).Mul(p.y, zinv)
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// Encode the sign of the y coordinate (indicated by the least significant
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// bit) as the encoding type (2 or 3).
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buf := append(out[:0], 2)
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buf[0] |= y.Bytes()[{{.p}}ElementLength-1] & 1
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buf = append(buf, x.Bytes()...)
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return buf
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}
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// Add sets q = p1 + p2, and returns q. The points may overlap.
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func (q *{{.P}}Point) Add(p1, p2 *{{.P}}Point) *{{.P}}Point {
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// Complete addition formula for a = -3 from "Complete addition formulas for
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// prime order elliptic curves" (https://eprint.iacr.org/2015/1060), §A.2.
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t0 := new({{.Element}}).Mul(p1.x, p2.x) // t0 := X1 * X2
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t1 := new({{.Element}}).Mul(p1.y, p2.y) // t1 := Y1 * Y2
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t2 := new({{.Element}}).Mul(p1.z, p2.z) // t2 := Z1 * Z2
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t3 := new({{.Element}}).Add(p1.x, p1.y) // t3 := X1 + Y1
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t4 := new({{.Element}}).Add(p2.x, p2.y) // t4 := X2 + Y2
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t3.Mul(t3, t4) // t3 := t3 * t4
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t4.Add(t0, t1) // t4 := t0 + t1
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t3.Sub(t3, t4) // t3 := t3 - t4
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t4.Add(p1.y, p1.z) // t4 := Y1 + Z1
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x3 := new({{.Element}}).Add(p2.y, p2.z) // X3 := Y2 + Z2
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t4.Mul(t4, x3) // t4 := t4 * X3
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x3.Add(t1, t2) // X3 := t1 + t2
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t4.Sub(t4, x3) // t4 := t4 - X3
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x3.Add(p1.x, p1.z) // X3 := X1 + Z1
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y3 := new({{.Element}}).Add(p2.x, p2.z) // Y3 := X2 + Z2
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x3.Mul(x3, y3) // X3 := X3 * Y3
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y3.Add(t0, t2) // Y3 := t0 + t2
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y3.Sub(x3, y3) // Y3 := X3 - Y3
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z3 := new({{.Element}}).Mul({{.p}}B(), t2) // Z3 := b * t2
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x3.Sub(y3, z3) // X3 := Y3 - Z3
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z3.Add(x3, x3) // Z3 := X3 + X3
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x3.Add(x3, z3) // X3 := X3 + Z3
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z3.Sub(t1, x3) // Z3 := t1 - X3
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x3.Add(t1, x3) // X3 := t1 + X3
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y3.Mul({{.p}}B(), y3) // Y3 := b * Y3
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t1.Add(t2, t2) // t1 := t2 + t2
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t2.Add(t1, t2) // t2 := t1 + t2
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y3.Sub(y3, t2) // Y3 := Y3 - t2
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y3.Sub(y3, t0) // Y3 := Y3 - t0
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t1.Add(y3, y3) // t1 := Y3 + Y3
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y3.Add(t1, y3) // Y3 := t1 + Y3
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t1.Add(t0, t0) // t1 := t0 + t0
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t0.Add(t1, t0) // t0 := t1 + t0
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t0.Sub(t0, t2) // t0 := t0 - t2
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t1.Mul(t4, y3) // t1 := t4 * Y3
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t2.Mul(t0, y3) // t2 := t0 * Y3
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y3.Mul(x3, z3) // Y3 := X3 * Z3
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y3.Add(y3, t2) // Y3 := Y3 + t2
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x3.Mul(t3, x3) // X3 := t3 * X3
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x3.Sub(x3, t1) // X3 := X3 - t1
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z3.Mul(t4, z3) // Z3 := t4 * Z3
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t1.Mul(t3, t0) // t1 := t3 * t0
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z3.Add(z3, t1) // Z3 := Z3 + t1
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q.x.Set(x3)
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q.y.Set(y3)
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q.z.Set(z3)
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return q
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}
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// Double sets q = p + p, and returns q. The points may overlap.
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func (q *{{.P}}Point) Double(p *{{.P}}Point) *{{.P}}Point {
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// Complete addition formula for a = -3 from "Complete addition formulas for
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// prime order elliptic curves" (https://eprint.iacr.org/2015/1060), §A.2.
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t0 := new({{.Element}}).Square(p.x) // t0 := X ^ 2
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t1 := new({{.Element}}).Square(p.y) // t1 := Y ^ 2
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t2 := new({{.Element}}).Square(p.z) // t2 := Z ^ 2
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t3 := new({{.Element}}).Mul(p.x, p.y) // t3 := X * Y
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t3.Add(t3, t3) // t3 := t3 + t3
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z3 := new({{.Element}}).Mul(p.x, p.z) // Z3 := X * Z
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z3.Add(z3, z3) // Z3 := Z3 + Z3
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y3 := new({{.Element}}).Mul({{.p}}B(), t2) // Y3 := b * t2
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y3.Sub(y3, z3) // Y3 := Y3 - Z3
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x3 := new({{.Element}}).Add(y3, y3) // X3 := Y3 + Y3
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y3.Add(x3, y3) // Y3 := X3 + Y3
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x3.Sub(t1, y3) // X3 := t1 - Y3
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y3.Add(t1, y3) // Y3 := t1 + Y3
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y3.Mul(x3, y3) // Y3 := X3 * Y3
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x3.Mul(x3, t3) // X3 := X3 * t3
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t3.Add(t2, t2) // t3 := t2 + t2
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t2.Add(t2, t3) // t2 := t2 + t3
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z3.Mul({{.p}}B(), z3) // Z3 := b * Z3
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z3.Sub(z3, t2) // Z3 := Z3 - t2
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z3.Sub(z3, t0) // Z3 := Z3 - t0
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t3.Add(z3, z3) // t3 := Z3 + Z3
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z3.Add(z3, t3) // Z3 := Z3 + t3
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t3.Add(t0, t0) // t3 := t0 + t0
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t0.Add(t3, t0) // t0 := t3 + t0
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t0.Sub(t0, t2) // t0 := t0 - t2
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t0.Mul(t0, z3) // t0 := t0 * Z3
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y3.Add(y3, t0) // Y3 := Y3 + t0
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t0.Mul(p.y, p.z) // t0 := Y * Z
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t0.Add(t0, t0) // t0 := t0 + t0
|
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z3.Mul(t0, z3) // Z3 := t0 * Z3
|
||
x3.Sub(x3, z3) // X3 := X3 - Z3
|
||
z3.Mul(t0, t1) // Z3 := t0 * t1
|
||
z3.Add(z3, z3) // Z3 := Z3 + Z3
|
||
z3.Add(z3, z3) // Z3 := Z3 + Z3
|
||
|
||
q.x.Set(x3)
|
||
q.y.Set(y3)
|
||
q.z.Set(z3)
|
||
return q
|
||
}
|
||
|
||
// Select sets q to p1 if cond == 1, and to p2 if cond == 0.
|
||
func (q *{{.P}}Point) Select(p1, p2 *{{.P}}Point, cond int) *{{.P}}Point {
|
||
q.x.Select(p1.x, p2.x, cond)
|
||
q.y.Select(p1.y, p2.y, cond)
|
||
q.z.Select(p1.z, p2.z, cond)
|
||
return q
|
||
}
|
||
|
||
// A {{.p}}Table holds the first 15 multiples of a point at offset -1, so [1]P
|
||
// is at table[0], [15]P is at table[14], and [0]P is implicitly the identity
|
||
// point.
|
||
type {{.p}}Table [15]*{{.P}}Point
|
||
|
||
// Select selects the n-th multiple of the table base point into p. It works in
|
||
// constant time by iterating over every entry of the table. n must be in [0, 15].
|
||
func (table *{{.p}}Table) Select(p *{{.P}}Point, n uint8) {
|
||
if n >= 16 {
|
||
panic("sm2ec: internal error: {{.p}}Table called with out-of-bounds value")
|
||
}
|
||
p.Set(New{{.P}}Point())
|
||
for i := uint8(1); i < 16; i++ {
|
||
cond := subtle.ConstantTimeByteEq(i, n)
|
||
p.Select(table[i-1], p, cond)
|
||
}
|
||
}
|
||
|
||
// ScalarMult sets p = scalar * q, and returns p.
|
||
func (p *{{.P}}Point) ScalarMult(q *{{.P}}Point, scalar []byte) (*{{.P}}Point, error) {
|
||
// Compute a {{.p}}Table for the base point q. The explicit New{{.P}}Point
|
||
// calls get inlined, letting the allocations live on the stack.
|
||
var table = {{.p}}Table{New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point(),
|
||
New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point(),
|
||
New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point(),
|
||
New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point(), New{{.P}}Point()}
|
||
table[0].Set(q)
|
||
for i := 1; i < 15; i += 2 {
|
||
table[i].Double(table[i/2])
|
||
table[i+1].Add(table[i], q)
|
||
}
|
||
// Instead of doing the classic double-and-add chain, we do it with a
|
||
// four-bit window: we double four times, and then add [0-15]P.
|
||
t := New{{.P}}Point()
|
||
p.Set(New{{.P}}Point())
|
||
for i, byte := range scalar {
|
||
// No need to double on the first iteration, as p is the identity at
|
||
// this point, and [N]∞ = ∞.
|
||
if i != 0 {
|
||
p.Double(p)
|
||
p.Double(p)
|
||
p.Double(p)
|
||
p.Double(p)
|
||
}
|
||
windowValue := byte >> 4
|
||
table.Select(t, windowValue)
|
||
p.Add(p, t)
|
||
p.Double(p)
|
||
p.Double(p)
|
||
p.Double(p)
|
||
p.Double(p)
|
||
windowValue = byte & 0b1111
|
||
table.Select(t, windowValue)
|
||
p.Add(p, t)
|
||
}
|
||
return p, nil
|
||
}
|
||
|
||
var {{.p}}GeneratorTable *[{{.p}}ElementLength * 2]{{.p}}Table
|
||
var {{.p}}GeneratorTableOnce sync.Once
|
||
|
||
// generatorTable returns a sequence of {{.p}}Tables. The first table contains
|
||
// multiples of G. Each successive table is the previous table doubled four
|
||
// times.
|
||
func (p *{{.P}}Point) generatorTable() *[{{.p}}ElementLength * 2]{{.p}}Table {
|
||
{{.p}}GeneratorTableOnce.Do(func() {
|
||
{{.p}}GeneratorTable = new([{{.p}}ElementLength * 2]{{.p}}Table)
|
||
base := New{{.P}}Point().SetGenerator()
|
||
for i := 0; i < {{.p}}ElementLength*2; i++ {
|
||
{{.p}}GeneratorTable[i][0] = New{{.P}}Point().Set(base)
|
||
for j := 1; j < 15; j++ {
|
||
{{.p}}GeneratorTable[i][j] = New{{.P}}Point().Add({{.p}}GeneratorTable[i][j-1], base)
|
||
}
|
||
base.Double(base)
|
||
base.Double(base)
|
||
base.Double(base)
|
||
base.Double(base)
|
||
}
|
||
})
|
||
return {{.p}}GeneratorTable
|
||
}
|
||
|
||
// ScalarBaseMult sets p = scalar * B, where B is the canonical generator, and
|
||
// returns p.
|
||
func (p *{{.P}}Point) ScalarBaseMult(scalar []byte) (*{{.P}}Point, error) {
|
||
if len(scalar) != {{.p}}ElementLength {
|
||
return nil, errors.New("invalid scalar length")
|
||
}
|
||
tables := p.generatorTable()
|
||
// This is also a scalar multiplication with a four-bit window like in
|
||
// ScalarMult, but in this case the doublings are precomputed. The value
|
||
// [windowValue]G added at iteration k would normally get doubled
|
||
// (totIterations-k)×4 times, but with a larger precomputation we can
|
||
// instead add [2^((totIterations-k)×4)][windowValue]G and avoid the
|
||
// doublings between iterations.
|
||
t := New{{.P}}Point()
|
||
p.Set(New{{.P}}Point())
|
||
tableIndex := len(tables) - 1
|
||
for _, byte := range scalar {
|
||
windowValue := byte >> 4
|
||
tables[tableIndex].Select(t, windowValue)
|
||
p.Add(p, t)
|
||
tableIndex--
|
||
|
||
windowValue = byte & 0b1111
|
||
tables[tableIndex].Select(t, windowValue)
|
||
p.Add(p, t)
|
||
tableIndex--
|
||
}
|
||
|
||
return p, nil
|
||
}
|
||
|
||
// {{.p}}Sqrt sets e to a square root of x. If x is not a square, {{.p}}Sqrt returns
|
||
// false and e is unchanged. e and x can overlap.
|
||
func {{.p}}Sqrt(e, x *{{ .Element }}) (isSquare bool) {
|
||
candidate := new({{ .Element }})
|
||
{{.p}}SqrtCandidate(candidate, x)
|
||
square := new({{ .Element }}).Square(candidate)
|
||
if square.Equal(x) != 1 {
|
||
return false
|
||
}
|
||
e.Set(candidate)
|
||
return true
|
||
}
|
||
`
|
||
|
||
const tmplAddchain = `
|
||
// sqrtCandidate sets z to a square root candidate for x. z and x must not overlap.
|
||
func sqrtCandidate(z, x *Element) {
|
||
// Since p = 3 mod 4, exponentiation by (p + 1) / 4 yields a square root candidate.
|
||
//
|
||
// The sequence of {{ .Ops.Adds }} multiplications and {{ .Ops.Doubles }} squarings is derived from the
|
||
// following addition chain generated with {{ .Meta.Module }} {{ .Meta.ReleaseTag }}.
|
||
//
|
||
{{- range lines (format .Script) }}
|
||
// {{ . }}
|
||
{{- end }}
|
||
//
|
||
{{- range .Program.Temporaries }}
|
||
var {{ . }} = new(Element)
|
||
{{- end }}
|
||
{{ range $i := .Program.Instructions -}}
|
||
{{- with add $i.Op }}
|
||
{{ $i.Output }}.Mul({{ .X }}, {{ .Y }})
|
||
{{- end -}}
|
||
{{- with double $i.Op }}
|
||
{{ $i.Output }}.Square({{ .X }})
|
||
{{- end -}}
|
||
{{- with shift $i.Op -}}
|
||
{{- $first := 0 -}}
|
||
{{- if ne $i.Output.Identifier .X.Identifier }}
|
||
{{ $i.Output }}.Square({{ .X }})
|
||
{{- $first = 1 -}}
|
||
{{- end }}
|
||
for s := {{ $first }}; s < {{ .S }}; s++ {
|
||
{{ $i.Output }}.Square({{ $i.Output }})
|
||
}
|
||
{{- end -}}
|
||
{{- end }}
|
||
}
|
||
`
|