Merge pull request #367 from OffchainLabs/re-add-bls12381

Re-add kilic BLS12-381 library

crypto/bls12381/arithmetic_decl.go

@@ -0,0 +1,84 @@
+// Copyright 2020 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+//go:build (amd64 && blsasm) || (amd64 && blsadx)
+// +build amd64,blsasm amd64,blsadx
+
+package bls12381
+
+import (
+	"golang.org/x/sys/cpu"
+)
+
+func init() {
+	if !enableADX || !cpu.X86.HasADX || !cpu.X86.HasBMI2 {
+		mul = mulNoADX
+	}
+}
+
+// Use ADX backend for default
+var mul func(c, a, b *fe) = mulADX
+
+func square(c, a *fe) {
+	mul(c, a, a)
+}
+
+func neg(c, a *fe) {
+	if a.isZero() {
+		c.set(a)
+	} else {
+		_neg(c, a)
+	}
+}
+
+//go:noescape
+func add(c, a, b *fe)
+
+//go:noescape
+func addAssign(a, b *fe)
+
+//go:noescape
+func ladd(c, a, b *fe)
+
+//go:noescape
+func laddAssign(a, b *fe)
+
+//go:noescape
+func double(c, a *fe)
+
+//go:noescape
+func doubleAssign(a *fe)
+
+//go:noescape
+func ldouble(c, a *fe)
+
+//go:noescape
+func sub(c, a, b *fe)
+
+//go:noescape
+func subAssign(a, b *fe)
+
+//go:noescape
+func lsubAssign(a, b *fe)
+
+//go:noescape
+func _neg(c, a *fe)
+
+//go:noescape
+func mulNoADX(c, a, b *fe)
+
+//go:noescape
+func mulADX(c, a, b *fe)