| // Copyright 2021 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Code generated by addchain. DO NOT EDIT. |
| |
| package fiat |
| |
| // Invert sets e = 1/x, and returns e. |
| // |
| // If x == 0, Invert returns e = 0. |
| func (e *P384Element) Invert(x *P384Element) *P384Element { |
| // Inversion is implemented as exponentiation with exponent p − 2. |
| // The sequence of 15 multiplications and 383 squarings is derived from the |
| // following addition chain generated with github.com/mmcloughlin/addchain v0.4.0. |
| // |
| // _10 = 2*1 |
| // _11 = 1 + _10 |
| // _110 = 2*_11 |
| // _111 = 1 + _110 |
| // _111000 = _111 << 3 |
| // _111111 = _111 + _111000 |
| // x12 = _111111 << 6 + _111111 |
| // x24 = x12 << 12 + x12 |
| // x30 = x24 << 6 + _111111 |
| // x31 = 2*x30 + 1 |
| // x32 = 2*x31 + 1 |
| // x63 = x32 << 31 + x31 |
| // x126 = x63 << 63 + x63 |
| // x252 = x126 << 126 + x126 |
| // x255 = x252 << 3 + _111 |
| // i397 = ((x255 << 33 + x32) << 94 + x30) << 2 |
| // return 1 + i397 |
| // |
| |
| var z = new(P384Element).Set(e) |
| var t0 = new(P384Element) |
| var t1 = new(P384Element) |
| var t2 = new(P384Element) |
| var t3 = new(P384Element) |
| |
| z.Square(x) |
| z.Mul(x, z) |
| z.Square(z) |
| t1.Mul(x, z) |
| z.Square(t1) |
| for s := 1; s < 3; s++ { |
| z.Square(z) |
| } |
| z.Mul(t1, z) |
| t0.Square(z) |
| for s := 1; s < 6; s++ { |
| t0.Square(t0) |
| } |
| t0.Mul(z, t0) |
| t2.Square(t0) |
| for s := 1; s < 12; s++ { |
| t2.Square(t2) |
| } |
| t0.Mul(t0, t2) |
| for s := 0; s < 6; s++ { |
| t0.Square(t0) |
| } |
| z.Mul(z, t0) |
| t0.Square(z) |
| t2.Mul(x, t0) |
| t0.Square(t2) |
| t0.Mul(x, t0) |
| t3.Square(t0) |
| for s := 1; s < 31; s++ { |
| t3.Square(t3) |
| } |
| t2.Mul(t2, t3) |
| t3.Square(t2) |
| for s := 1; s < 63; s++ { |
| t3.Square(t3) |
| } |
| t2.Mul(t2, t3) |
| t3.Square(t2) |
| for s := 1; s < 126; s++ { |
| t3.Square(t3) |
| } |
| t2.Mul(t2, t3) |
| for s := 0; s < 3; s++ { |
| t2.Square(t2) |
| } |
| t1.Mul(t1, t2) |
| for s := 0; s < 33; s++ { |
| t1.Square(t1) |
| } |
| t0.Mul(t0, t1) |
| for s := 0; s < 94; s++ { |
| t0.Square(t0) |
| } |
| z.Mul(z, t0) |
| for s := 0; s < 2; s++ { |
| z.Square(z) |
| } |
| z.Mul(x, z) |
| |
| return e.Set(z) |
| } |