open-nomad/vendor/golang.org/x/crypto/poly1305/bits_compat.go
Seth Hoenig 435c0d9fc8 deps: Switch to Go modules for dependency management
This PR switches the Nomad repository from using govendor to Go modules
for managing dependencies. Aspects of the Nomad workflow remain pretty
much the same. The usual Makefile targets should continue to work as
they always did. The API submodule simply defers to the parent Nomad
version on the repository, keeping the semantics of API versioning that
currently exists.
2020-06-02 14:30:36 -05:00

40 lines
937 B
Go

// Copyright 2019 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.
// +build !go1.13
package poly1305
// Generic fallbacks for the math/bits intrinsics, copied from
// src/math/bits/bits.go. They were added in Go 1.12, but Add64 and Sum64 had
// variable time fallbacks until Go 1.13.
func bitsAdd64(x, y, carry uint64) (sum, carryOut uint64) {
sum = x + y + carry
carryOut = ((x & y) | ((x | y) &^ sum)) >> 63
return
}
func bitsSub64(x, y, borrow uint64) (diff, borrowOut uint64) {
diff = x - y - borrow
borrowOut = ((^x & y) | (^(x ^ y) & diff)) >> 63
return
}
func bitsMul64(x, y uint64) (hi, lo uint64) {
const mask32 = 1<<32 - 1
x0 := x & mask32
x1 := x >> 32
y0 := y & mask32
y1 := y >> 32
w0 := x0 * y0
t := x1*y0 + w0>>32
w1 := t & mask32
w2 := t >> 32
w1 += x0 * y1
hi = x1*y1 + w2 + w1>>32
lo = x * y
return
}