openssl/crypto/poly1305/poly1305_arm.c - platform/external/chromium_org/third_party/openssl - Git at Google

 /* ====================================================================
  * Copyright (c) 2011-2013 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. All advertising materials mentioning features or use of this
  *    software must display the following acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  *
  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  *    endorse or promote products derived from this software without
  *    prior written permission. For written permission, please contact
  *    licensing@OpenSSL.org.
  *
  * 5. Products derived from this software may not be called "OpenSSL"
  *    nor may "OpenSSL" appear in their names without prior written
  *    permission of the OpenSSL Project.
  *
  * 6. Redistributions of any form whatsoever must retain the following
  *    acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  *
  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  * ====================================================================
  */

 /* This implementation was taken from the public domain, neon2 version in
  * SUPERCOP by D. J. Bernstein and Peter Schwabe. */

 #include <stdint.h>
 #include <string.h>

 #include <openssl/poly1305.h>

 #if !defined(OPENSSL_NO_POLY1305)

 typedef struct {
   uint32_t v[12]; /* for alignment; only using 10 */
 } fe1305x2;

 #define addmulmod openssl_poly1305_neon2_addmulmod
 #define blocks openssl_poly1305_neon2_blocks

 extern void addmulmod(fe1305x2 *r, const fe1305x2 *x, const fe1305x2 *y, const fe1305x2 *c);

 extern int blocks(fe1305x2 *h, const fe1305x2 *precomp, const unsigned char *in, unsigned int inlen);

 static void freeze(fe1305x2 *r)
 	{
 	int i;

 	uint32_t x0 = r->v[0];
 	uint32_t x1 = r->v[2];
 	uint32_t x2 = r->v[4];
 	uint32_t x3 = r->v[6];
 	uint32_t x4 = r->v[8];
 	uint32_t y0;
 	uint32_t y1;
 	uint32_t y2;
 	uint32_t y3;
 	uint32_t y4;
 	uint32_t swap;

 	for (i = 0;i < 3;++i)
 		{
 		x1 += x0 >> 26; x0 &= 0x3ffffff;
 		x2 += x1 >> 26; x1 &= 0x3ffffff;
 		x3 += x2 >> 26; x2 &= 0x3ffffff;
 		x4 += x3 >> 26; x3 &= 0x3ffffff;
 		x0 += 5*(x4 >> 26); x4 &= 0x3ffffff;
 		}

 	y0 = x0 + 5;
 	y1 = x1 + (y0 >> 26); y0 &= 0x3ffffff;
 	y2 = x2 + (y1 >> 26); y1 &= 0x3ffffff;
 	y3 = x3 + (y2 >> 26); y2 &= 0x3ffffff;
 	y4 = x4 + (y3 >> 26); y3 &= 0x3ffffff;
 	swap = -(y4 >> 26); y4 &= 0x3ffffff;

 	y0 ^= x0;
 	y1 ^= x1;
 	y2 ^= x2;
 	y3 ^= x3;
 	y4 ^= x4;

 	y0 &= swap;
 	y1 &= swap;
 	y2 &= swap;
 	y3 &= swap;
 	y4 &= swap;

 	y0 ^= x0;
 	y1 ^= x1;
 	y2 ^= x2;
 	y3 ^= x3;
 	y4 ^= x4;

 	r->v[0] = y0;
 	r->v[2] = y1;
 	r->v[4] = y2;
 	r->v[6] = y3;
 	r->v[8] = y4;
 	}

 static void fe1305x2_tobytearray(unsigned char *r, fe1305x2 *x)
 	{
 	uint32_t x0 = x->v[0];
 	uint32_t x1 = x->v[2];
 	uint32_t x2 = x->v[4];
 	uint32_t x3 = x->v[6];
 	uint32_t x4 = x->v[8];

 	x1 += x0 >> 26;
 	x0 &= 0x3ffffff;
 	x2 += x1 >> 26;
 	x1 &= 0x3ffffff;
 	x3 += x2 >> 26;
 	x2 &= 0x3ffffff;
 	x4 += x3 >> 26;
 	x3 &= 0x3ffffff;

 	*(uint32_t *) r = x0 + (x1 << 26);
 	*(uint32_t *) (r + 4) = (x1 >> 6) + (x2 << 20);
 	*(uint32_t *) (r + 8) = (x2 >> 12) + (x3 << 14);
 	*(uint32_t *) (r + 12) = (x3 >> 18) + (x4 << 8);
 	}

 /* load32 exists to avoid breaking strict aliasing rules in
  * fe1305x2_frombytearray. */
 static uint32_t load32(unsigned char *t)
 	{
 	uint32_t tmp;
 	memcpy(&tmp, t, sizeof(tmp));
 	return tmp;
 	}

 static void fe1305x2_frombytearray(fe1305x2 *r, const unsigned char *x, unsigned long long xlen)
 	{
 	int i;
 	unsigned char t[17];

 	for (i = 0; (i < 16) && (i < xlen); i++)
 		t[i] = x[i];
 	xlen -= i;
 	x += i;
 	t[i++] = 1;
 	for (; i<17; i++)
 		t[i] = 0;

 	r->v[0] = 0x3ffffff & load32(t);
 	r->v[2] = 0x3ffffff & (load32(t + 3) >> 2);
 	r->v[4] = 0x3ffffff & (load32(t + 6) >> 4);
 	r->v[6] = 0x3ffffff & (load32(t + 9) >> 6);
 	r->v[8] = load32(t + 13);

 	if (xlen)
 		{
 		for (i = 0; (i < 16) && (i < xlen); i++)
 			t[i] = x[i];
 		t[i++] = 1;
 		for (; i<17; i++)
 			t[i] = 0;

 		r->v[1] = 0x3ffffff & load32(t);
 		r->v[3] = 0x3ffffff & (load32(t + 3) >> 2);
 		r->v[5] = 0x3ffffff & (load32(t + 6) >> 4);
 		r->v[7] = 0x3ffffff & (load32(t + 9) >> 6);
 		r->v[9] = load32(t + 13);
 		}
 	else
 		r->v[1] = r->v[3] = r->v[5] = r->v[7] = r->v[9] = 0;
 	}

 static const fe1305x2 zero __attribute__ ((aligned (16)));

 struct poly1305_state_st {
 	unsigned char data[sizeof(fe1305x2[5]) + 128];
 	unsigned char buf[32];
 	unsigned int buf_used;
 	unsigned char key[16];
 };

 void CRYPTO_poly1305_init_neon(poly1305_state *state,
 			       const unsigned char key[32])
 	{
 	struct poly1305_state_st *st = (struct poly1305_state_st*) (state);
 	fe1305x2 *const r = (fe1305x2 *) (st->data + (15 & (-(int) st->data)));
 	fe1305x2 *const h = r + 1;
 	fe1305x2 *const c = h + 1;
 	fe1305x2 *const precomp = c + 1;
 	unsigned int j;

 	r->v[1] = r->v[0] = 0x3ffffff & *(uint32_t *) key;
 	r->v[3] = r->v[2] = 0x3ffff03 & ((*(uint32_t *) (key + 3)) >> 2);
 	r->v[5] = r->v[4] = 0x3ffc0ff & ((*(uint32_t *) (key + 6)) >> 4);
 	r->v[7] = r->v[6] = 0x3f03fff & ((*(uint32_t *) (key + 9)) >> 6);
 	r->v[9] = r->v[8] = 0x00fffff & ((*(uint32_t *) (key + 12)) >> 8);

 	for (j = 0; j < 10; j++)
 		h->v[j] = 0; /* XXX: should fast-forward a bit */

 	addmulmod(precomp,r,r,&zero);                 /* precompute r^2 */
 	addmulmod(precomp + 1,precomp,precomp,&zero); /* precompute r^4 */

 	memcpy(st->key, key + 16, 16);
 	st->buf_used = 0;
 	}

 void CRYPTO_poly1305_update_neon(poly1305_state *state, const unsigned char *in,
 				 size_t in_len)
 	{
 	struct poly1305_state_st *st = (struct poly1305_state_st*) (state);
 	fe1305x2 *const r = (fe1305x2 *) (st->data + (15 & (-(int) st->data)));
 	fe1305x2 *const h = r + 1;
 	fe1305x2 *const c = h + 1;
 	fe1305x2 *const precomp = c + 1;
 	unsigned int i;

 	if (st->buf_used)
 		{
 		unsigned int todo = 32 - st->buf_used;
 		if (todo > in_len)
 			todo = in_len;
 		for (i = 0; i < todo; i++)
 			st->buf[st->buf_used + i] = in[i];
 		st->buf_used += todo;
 		in_len -= todo;
 		in += todo;

 		if (st->buf_used == sizeof(st->buf) && in_len)
 			{
 			addmulmod(h,h,precomp,&zero);
 			fe1305x2_frombytearray(c, st->buf, sizeof(st->buf));
 			for (i = 0; i < 10; i++)
 				h->v[i] += c->v[i];
 			st->buf_used = 0;
 			}
 		}

 	while (in_len > 32)
 		{
 		unsigned int tlen = 1048576;
 		if (in_len < tlen)
 			tlen = in_len;
 		tlen -= blocks(h, precomp, in, tlen);
 		in_len -= tlen;
 		in += tlen;
 		}

 	if (in_len)
 		{
 		for (i = 0; i < in_len; i++)
 			st->buf[i] = in[i];
 		st->buf_used = in_len;
 		}
 	}

 void CRYPTO_poly1305_finish_neon(poly1305_state* state, unsigned char mac[16])
 	{
 	struct poly1305_state_st *st = (struct poly1305_state_st*) (state);
 	fe1305x2 *const r = (fe1305x2 *) (st->data + (15 & (-(int) st->data)));
 	fe1305x2 *const h = r + 1;
 	fe1305x2 *const c = h + 1;
 	fe1305x2 *const precomp = c + 1;

 	addmulmod(h,h,precomp,&zero);

 	if (st->buf_used > 16)
 		{
 		fe1305x2_frombytearray(c, st->buf, st->buf_used);
 		precomp->v[1] = r->v[1];
 		precomp->v[3] = r->v[3];
 		precomp->v[5] = r->v[5];
 		precomp->v[7] = r->v[7];
 		precomp->v[9] = r->v[9];
 		addmulmod(h,h,precomp,c);
 		}
 	else if (st->buf_used > 0)
 		{
 		fe1305x2_frombytearray(c, st->buf, st->buf_used);
 		r->v[1] = 1;
 		r->v[3] = 0;
 		r->v[5] = 0;
 		r->v[7] = 0;
 		r->v[9] = 0;
 		addmulmod(h,h,r,c);
 		}

 	h->v[0] += h->v[1];
 	h->v[2] += h->v[3];
 	h->v[4] += h->v[5];
 	h->v[6] += h->v[7];
 	h->v[8] += h->v[9];
 	freeze(h);

 	fe1305x2_frombytearray(c, st->key, 16);
 	c->v[8] ^= (1 << 24);

 	h->v[0] += c->v[0];
 	h->v[2] += c->v[2];
 	h->v[4] += c->v[4];
 	h->v[6] += c->v[6];
 	h->v[8] += c->v[8];
 	fe1305x2_tobytearray(mac, h);
 	}

 #endif  /* !OPENSSL_NO_POLY1305 */
	/* ====================================================================
	* Copyright (c) 2011-2013 The OpenSSL Project. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. All advertising materials mentioning features or use of this
	* software must display the following acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
	*
	* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
	* endorse or promote products derived from this software without
	* prior written permission. For written permission, please contact
	* licensing@OpenSSL.org.
	*
	* 5. Products derived from this software may not be called "OpenSSL"
	* nor may "OpenSSL" appear in their names without prior written
	* permission of the OpenSSL Project.
	*
	* 6. Redistributions of any form whatsoever must retain the following
	* acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
	*
	* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
	* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	* OF THE POSSIBILITY OF SUCH DAMAGE.
	* ====================================================================
	*/

	/* This implementation was taken from the public domain, neon2 version in
	* SUPERCOP by D. J. Bernstein and Peter Schwabe. */

	#include <stdint.h>
	#include <string.h>

	#include <openssl/poly1305.h>

	#if !defined(OPENSSL_NO_POLY1305)

	typedef struct {
	uint32_t v[12]; /* for alignment; only using 10 */
	} fe1305x2;

	#define addmulmod openssl_poly1305_neon2_addmulmod
	#define blocks openssl_poly1305_neon2_blocks

	extern void addmulmod(fe1305x2 r, const fe1305x2 x, const fe1305x2 y, const fe1305x2 c);

	extern int blocks(fe1305x2 h, const fe1305x2 precomp, const unsigned char *in, unsigned int inlen);

	static void freeze(fe1305x2 *r)
	{
	int i;

	uint32_t x0 = r->v[0];
	uint32_t x1 = r->v[2];
	uint32_t x2 = r->v[4];
	uint32_t x3 = r->v[6];
	uint32_t x4 = r->v[8];
	uint32_t y0;
	uint32_t y1;
	uint32_t y2;
	uint32_t y3;
	uint32_t y4;
	uint32_t swap;

	for (i = 0;i < 3;++i)
	{
	x1 += x0 >> 26; x0 &= 0x3ffffff;
	x2 += x1 >> 26; x1 &= 0x3ffffff;
	x3 += x2 >> 26; x2 &= 0x3ffffff;
	x4 += x3 >> 26; x3 &= 0x3ffffff;
	x0 += 5*(x4 >> 26); x4 &= 0x3ffffff;
	}

	y0 = x0 + 5;
	y1 = x1 + (y0 >> 26); y0 &= 0x3ffffff;
	y2 = x2 + (y1 >> 26); y1 &= 0x3ffffff;
	y3 = x3 + (y2 >> 26); y2 &= 0x3ffffff;
	y4 = x4 + (y3 >> 26); y3 &= 0x3ffffff;
	swap = -(y4 >> 26); y4 &= 0x3ffffff;

	y0 ^= x0;
	y1 ^= x1;
	y2 ^= x2;
	y3 ^= x3;
	y4 ^= x4;

	y0 &= swap;
	y1 &= swap;
	y2 &= swap;
	y3 &= swap;
	y4 &= swap;

	y0 ^= x0;
	y1 ^= x1;
	y2 ^= x2;
	y3 ^= x3;
	y4 ^= x4;

	r->v[0] = y0;
	r->v[2] = y1;
	r->v[4] = y2;
	r->v[6] = y3;
	r->v[8] = y4;
	}

	static void fe1305x2_tobytearray(unsigned char r, fe1305x2 x)
	{
	uint32_t x0 = x->v[0];
	uint32_t x1 = x->v[2];
	uint32_t x2 = x->v[4];
	uint32_t x3 = x->v[6];
	uint32_t x4 = x->v[8];

	x1 += x0 >> 26;
	x0 &= 0x3ffffff;
	x2 += x1 >> 26;
	x1 &= 0x3ffffff;
	x3 += x2 >> 26;
	x2 &= 0x3ffffff;
	x4 += x3 >> 26;
	x3 &= 0x3ffffff;

	(uint32_t ) r = x0 + (x1 << 26);
	(uint32_t ) (r + 4) = (x1 >> 6) + (x2 << 20);
	(uint32_t ) (r + 8) = (x2 >> 12) + (x3 << 14);
	(uint32_t ) (r + 12) = (x3 >> 18) + (x4 << 8);
	}

	/* load32 exists to avoid breaking strict aliasing rules in
	* fe1305x2_frombytearray. */
	static uint32_t load32(unsigned char *t)
	{
	uint32_t tmp;
	memcpy(&tmp, t, sizeof(tmp));
	return tmp;
	}

	static void fe1305x2_frombytearray(fe1305x2 r, const unsigned char x, unsigned long long xlen)
	{
	int i;
	unsigned char t[17];

	for (i = 0; (i < 16) && (i < xlen); i++)
	t[i] = x[i];
	xlen -= i;
	x += i;
	t[i++] = 1;
	for (; i<17; i++)
	t[i] = 0;

	r->v[0] = 0x3ffffff & load32(t);
	r->v[2] = 0x3ffffff & (load32(t + 3) >> 2);
	r->v[4] = 0x3ffffff & (load32(t + 6) >> 4);
	r->v[6] = 0x3ffffff & (load32(t + 9) >> 6);
	r->v[8] = load32(t + 13);

	if (xlen)
	{
	for (i = 0; (i < 16) && (i < xlen); i++)
	t[i] = x[i];
	t[i++] = 1;
	for (; i<17; i++)
	t[i] = 0;

	r->v[1] = 0x3ffffff & load32(t);
	r->v[3] = 0x3ffffff & (load32(t + 3) >> 2);
	r->v[5] = 0x3ffffff & (load32(t + 6) >> 4);
	r->v[7] = 0x3ffffff & (load32(t + 9) >> 6);
	r->v[9] = load32(t + 13);
	}
	else
	r->v[1] = r->v[3] = r->v[5] = r->v[7] = r->v[9] = 0;
	}

	static const fe1305x2 zero __attribute__ ((aligned (16)));

	struct poly1305_state_st {
	unsigned char data[sizeof(fe1305x2[5]) + 128];
	unsigned char buf[32];
	unsigned int buf_used;
	unsigned char key[16];
	};

	void CRYPTO_poly1305_init_neon(poly1305_state *state,
	const unsigned char key[32])
	{
	struct poly1305_state_st st = (struct poly1305_state_st) (state);
	fe1305x2 const r = (fe1305x2 ) (st->data + (15 & (-(int) st->data)));
	fe1305x2 *const h = r + 1;
	fe1305x2 *const c = h + 1;
	fe1305x2 *const precomp = c + 1;
	unsigned int j;

	r->v[1] = r->v[0] = 0x3ffffff & (uint32_t ) key;
	r->v[3] = r->v[2] = 0x3ffff03 & (((uint32_t ) (key + 3)) >> 2);
	r->v[5] = r->v[4] = 0x3ffc0ff & (((uint32_t ) (key + 6)) >> 4);
	r->v[7] = r->v[6] = 0x3f03fff & (((uint32_t ) (key + 9)) >> 6);
	r->v[9] = r->v[8] = 0x00fffff & (((uint32_t ) (key + 12)) >> 8);

	for (j = 0; j < 10; j++)
	h->v[j] = 0; /* XXX: should fast-forward a bit */

	addmulmod(precomp,r,r,&zero); /* precompute r^2 */
	addmulmod(precomp + 1,precomp,precomp,&zero); /* precompute r^4 */

	memcpy(st->key, key + 16, 16);
	st->buf_used = 0;
	}

	void CRYPTO_poly1305_update_neon(poly1305_state state, const unsigned char in,
	size_t in_len)
	{
	struct poly1305_state_st st = (struct poly1305_state_st) (state);
	fe1305x2 const r = (fe1305x2 ) (st->data + (15 & (-(int) st->data)));
	fe1305x2 *const h = r + 1;
	fe1305x2 *const c = h + 1;
	fe1305x2 *const precomp = c + 1;
	unsigned int i;

	if (st->buf_used)
	{
	unsigned int todo = 32 - st->buf_used;
	if (todo > in_len)
	todo = in_len;
	for (i = 0; i < todo; i++)
	st->buf[st->buf_used + i] = in[i];
	st->buf_used += todo;
	in_len -= todo;
	in += todo;

	if (st->buf_used == sizeof(st->buf) && in_len)
	{
	addmulmod(h,h,precomp,&zero);
	fe1305x2_frombytearray(c, st->buf, sizeof(st->buf));
	for (i = 0; i < 10; i++)
	h->v[i] += c->v[i];
	st->buf_used = 0;
	}
	}

	while (in_len > 32)
	{
	unsigned int tlen = 1048576;
	if (in_len < tlen)
	tlen = in_len;
	tlen -= blocks(h, precomp, in, tlen);
	in_len -= tlen;
	in += tlen;
	}

	if (in_len)
	{
	for (i = 0; i < in_len; i++)
	st->buf[i] = in[i];
	st->buf_used = in_len;
	}
	}

	void CRYPTO_poly1305_finish_neon(poly1305_state* state, unsigned char mac[16])
	{
	struct poly1305_state_st st = (struct poly1305_state_st) (state);
	fe1305x2 const r = (fe1305x2 ) (st->data + (15 & (-(int) st->data)));
	fe1305x2 *const h = r + 1;
	fe1305x2 *const c = h + 1;
	fe1305x2 *const precomp = c + 1;

	addmulmod(h,h,precomp,&zero);

	if (st->buf_used > 16)
	{
	fe1305x2_frombytearray(c, st->buf, st->buf_used);
	precomp->v[1] = r->v[1];
	precomp->v[3] = r->v[3];
	precomp->v[5] = r->v[5];
	precomp->v[7] = r->v[7];
	precomp->v[9] = r->v[9];
	addmulmod(h,h,precomp,c);
	}
	else if (st->buf_used > 0)
	{
	fe1305x2_frombytearray(c, st->buf, st->buf_used);
	r->v[1] = 1;
	r->v[3] = 0;
	r->v[5] = 0;
	r->v[7] = 0;
	r->v[9] = 0;
	addmulmod(h,h,r,c);
	}

	h->v[0] += h->v[1];
	h->v[2] += h->v[3];
	h->v[4] += h->v[5];
	h->v[6] += h->v[7];
	h->v[8] += h->v[9];
	freeze(h);

	fe1305x2_frombytearray(c, st->key, 16);
	c->v[8] ^= (1 << 24);

	h->v[0] += c->v[0];
	h->v[2] += c->v[2];
	h->v[4] += c->v[4];
	h->v[6] += c->v[6];
	h->v[8] += c->v[8];
	fe1305x2_tobytearray(mac, h);
	}

	#endif /* !OPENSSL_NO_POLY1305 */