P2Pool/edwards25519
P2Pool/edwards25519
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crypto/internal/edwards25519: reduce Point size by reordering fields

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Updates #58483

Tested on Linux amd64:
  type Element struct {
    l0, l1, l2, l3, l4 uint64
  }

  type PointAfter struct {
    x, y, z, t Element
    _          incomparable
  }

  type PointBefore struct {
    _          incomparable
    x, y, z, t Element
  }

  type incomparable [0]func()

  func main() {
    fmt.Println(unsafe.Sizeof(PointAfter{})) // 168
    fmt.Println(unsafe.Sizeof(PointBefore{})) // 160
  }

Change-Id: I6c4fcb586bbf3febf62b6e54608496ff81685e43
Reviewed-on: https://go-review.googlesource.com/c/go/+/467616
Reviewed-by: Roland Shoemaker <roland@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
This commit is contained in:
Jorropo 2023-02-13 01:48:57 +01:00 committed by Filippo Valsorda
parent daffb31912
commit c901e5ec3c
1 changed files with 4 additions and 4 deletions
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8
edwards25519.go
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@ -27,13 +27,13 @@ type projP2 struct {
//
// The zero value is NOT valid, and it may be used only as a receiver.
type Point struct {
// The point is internally represented in extended coordinates (X, Y, Z, T)
// where x = X/Z, y = Y/Z, and xy = T/Z per https://eprint.iacr.org/2008/522.
x, y, z, t field.Element
// Make the type not comparable (i.e. used with == or as a map key), as
// equivalent points can be represented by different Go values.
_ incomparable
// The point is internally represented in extended coordinates (X, Y, Z, T)
// where x = X/Z, y = Y/Z, and xy = T/Z per https://eprint.iacr.org/2008/522.
x, y, z, t field.Element
}
type incomparable [0]func()