ran go mod vendor on the whole project

vendor/golang.org/x/crypto/poly1305/sum_amd64.go

@@ -6,63 +6,17 @@
 
 package poly1305
 
+// This function is implemented in sum_amd64.s
 //go:noescape
-func initialize(state *[7]uint64, key *[32]byte)
-
-//go:noescape
-func update(state *[7]uint64, msg []byte)
-
-//go:noescape
-func finalize(tag *[TagSize]byte, state *[7]uint64)
+func poly1305(out *[16]byte, m *byte, mlen uint64, key *[32]byte)
 
 // Sum generates an authenticator for m using a one-time key and puts the
 // 16-byte result into out. Authenticating two different messages with the same
 // key allows an attacker to forge messages at will.
 func Sum(out *[16]byte, m []byte, key *[32]byte) {
-	h := newMAC(key)
-	h.Write(m)
-	h.Sum(out)
-}
-
-func newMAC(key *[32]byte) (h mac) {
-	initialize(&h.state, key)
-	return
-}
-
-type mac struct {
-	state [7]uint64 // := uint64{ h0, h1, h2, r0, r1, pad0, pad1 }
-
-	buffer [TagSize]byte
-	offset int
-}
-
-func (h *mac) Write(p []byte) (n int, err error) {
-	n = len(p)
-	if h.offset > 0 {
-		remaining := TagSize - h.offset
-		if n < remaining {
-			h.offset += copy(h.buffer[h.offset:], p)
-			return n, nil
-		}
-		copy(h.buffer[h.offset:], p[:remaining])
-		p = p[remaining:]
-		h.offset = 0
-		update(&h.state, h.buffer[:])
+	var mPtr *byte
+	if len(m) > 0 {
+		mPtr = &m[0]
 	}
-	if nn := len(p) - (len(p) % TagSize); nn > 0 {
-		update(&h.state, p[:nn])
-		p = p[nn:]
-	}
-	if len(p) > 0 {
-		h.offset += copy(h.buffer[h.offset:], p)
-	}
-	return n, nil
-}
-
-func (h *mac) Sum(out *[16]byte) {
-	state := h.state
-	if h.offset > 0 {
-		update(&state, h.buffer[:h.offset])
-	}
-	finalize(out, &state)
+	poly1305(out, mPtr, uint64(len(m)), key)
 }