Staging: add echo cancelation module

This is used by mISDN and Zaptel drivers.

From: Steve Underwood <[e-mail]>
From: David Rowe <[e-mail]>
Cc: Tzafrir Cohen <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/Kconfig

···
 
 source "drivers/staging/wlan-ng/Kconfig"
 
+source "drivers/staging/echo/Kconfig"
+
 endif # STAGING

drivers/staging/Makefile

···
 obj-$(CONFIG_USB_IP_COMMON)	+= usbip/
 obj-$(CONFIG_W35UND)		+= winbond/
 obj-$(CONFIG_PRISM2_USB)	+= wlan-ng/
+obj-$(CONFIG_ECHO)		+= echo/

drivers/staging/echo/Kconfig

···
+config ECHO
+	tristate "Line Echo Canceller support"
+	default n
+	---help---
+	  This driver provides line echo cancelling support for mISDN and
+	  Zaptel drivers.
+
+	  To compile this driver as a module, choose M here. The module
+	  will be called echo.

drivers/staging/echo/Makefile

···
+obj-$(CONFIG_ECHO) += echo.o

drivers/staging/echo/TODO

···
+TODO:
+	- checkpatch.pl cleanups
+	- Lindent
+	- typedef removals
+	- handle bit_operations.h (merge in or make part of common code?)
+	- remove proc interface, only use echo.h interface (proc interface is
+	  racy and not correct.)
+
+Please send patches to Greg Kroah-Hartman <[e-mail]> and Cc: Steve
+Underwood <[e-mail]> and David Rowe <[e-mail]>

drivers/staging/echo/bit_operations.h

···
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * bit_operations.h - Various bit level operations, such as bit reversal
+ *
+ * Written by Steve Underwood <[e-mail]>
+ *
+ * Copyright (C) 2006 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: bit_operations.h,v 1.11 2006/11/28 15:37:03 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_BIT_OPERATIONS_H_)
+#define _BIT_OPERATIONS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(__i386__)  ||  defined(__x86_64__)
+/*! \brief Find the bit position of the highest set bit in a word
+    \param bits The word to be searched
+    \return The bit number of the highest set bit, or -1 if the word is zero. */
+static __inline__ int top_bit(unsigned int bits)
+{
+    int res;
+
+    __asm__ (" xorl %[res],%[res];\n"
+             " decl %[res];\n"
+             " bsrl %[bits],%[res]\n"
+             : [res] "=&r" (res)
+             : [bits] "rm" (bits));
+    return res;
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the bit position of the lowest set bit in a word
+    \param bits The word to be searched
+    \return The bit number of the lowest set bit, or -1 if the word is zero. */
+static __inline__ int bottom_bit(unsigned int bits)
+{
+    int res;
+
+    __asm__ (" xorl %[res],%[res];\n"
+             " decl %[res];\n"
+             " bsfl %[bits],%[res]\n"
+             : [res] "=&r" (res)
+             : [bits] "rm" (bits));
+    return res;
+}
+/*- End of function --------------------------------------------------------*/
+#else
+static __inline__ int top_bit(unsigned int bits)
+{
+    int i;
+
+    if (bits == 0)
+        return -1;
+    i = 0;
+    if (bits & 0xFFFF0000)
+    {
+        bits &= 0xFFFF0000;
+        i += 16;
+    }
+    if (bits & 0xFF00FF00)
+    {
+        bits &= 0xFF00FF00;
+        i += 8;
+    }
+    if (bits & 0xF0F0F0F0)
+    {
+        bits &= 0xF0F0F0F0;
+        i += 4;
+    }
+    if (bits & 0xCCCCCCCC)
+    {
+        bits &= 0xCCCCCCCC;
+        i += 2;
+    }
+    if (bits & 0xAAAAAAAA)
+    {
+        bits &= 0xAAAAAAAA;
+        i += 1;
+    }
+    return i;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int bottom_bit(unsigned int bits)
+{
+    int i;
+
+    if (bits == 0)
+        return -1;
+    i = 32;
+    if (bits & 0x0000FFFF)
+    {
+        bits &= 0x0000FFFF;
+        i -= 16;
+    }
+    if (bits & 0x00FF00FF)
+    {
+        bits &= 0x00FF00FF;
+        i -= 8;
+    }
+    if (bits & 0x0F0F0F0F)
+    {
+        bits &= 0x0F0F0F0F;
+        i -= 4;
+    }
+    if (bits & 0x33333333)
+    {
+        bits &= 0x33333333;
+        i -= 2;
+    }
+    if (bits & 0x55555555)
+    {
+        bits &= 0x55555555;
+        i -= 1;
+    }
+    return i;
+}
+/*- End of function --------------------------------------------------------*/
+#endif
+
+/*! \brief Bit reverse a byte.
+    \param data The byte to be reversed.
+    \return The bit reversed version of data. */
+static __inline__ uint8_t bit_reverse8(uint8_t x)
+{
+#if defined(__i386__)  ||  defined(__x86_64__)
+    /* If multiply is fast */
+    return ((x*0x0802U & 0x22110U) | (x*0x8020U & 0x88440U))*0x10101U >> 16;
+#else
+    /* If multiply is slow, but we have a barrel shifter */
+    x = (x >> 4) | (x << 4);
+    x = ((x & 0xCC) >> 2) | ((x & 0x33) << 2);
+    return ((x & 0xAA) >> 1) | ((x & 0x55) << 1);
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Bit reverse a 16 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+uint16_t bit_reverse16(uint16_t data);
+
+/*! \brief Bit reverse a 32 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+uint32_t bit_reverse32(uint32_t data);
+
+/*! \brief Bit reverse each of the four bytes in a 32 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+uint32_t bit_reverse_4bytes(uint32_t data);
+
+/*! \brief Find the number of set bits in a 32 bit word.
+    \param x The word to be searched.
+    \return The number of set bits. */
+int one_bits32(uint32_t x);
+
+/*! \brief Create a mask as wide as the number in a 32 bit word.
+    \param x The word to be searched.
+    \return The mask. */
+uint32_t make_mask32(uint32_t x);
+
+/*! \brief Create a mask as wide as the number in a 16 bit word.
+    \param x The word to be searched.
+    \return The mask. */
+uint16_t make_mask16(uint16_t x);
+
+/*! \brief Find the least significant one in a word, and return a word
+           with just that bit set.
+    \param x The word to be searched.
+    \return The word with the single set bit. */
+static __inline__ uint32_t least_significant_one32(uint32_t x)
+{
+    return (x & (-(int32_t) x));
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the most significant one in a word, and return a word
+           with just that bit set.
+    \param x The word to be searched.
+    \return The word with the single set bit. */
+static __inline__ uint32_t most_significant_one32(uint32_t x)
+{
+#if defined(__i386__)  ||  defined(__x86_64__)
+    return 1 << top_bit(x);
+#else
+    x = make_mask32(x);
+    return (x ^ (x >> 1));
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the parity of a byte.
+    \param x The byte to be checked.
+    \return 1 for odd, or 0 for even. */
+static __inline__ int parity8(uint8_t x)
+{
+    x = (x ^ (x >> 4)) & 0x0F;
+    return (0x6996 >> x) & 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the parity of a 16 bit word.
+    \param x The word to be checked.
+    \return 1 for odd, or 0 for even. */
+static __inline__ int parity16(uint16_t x)
+{
+    x ^= (x >> 8);
+    x = (x ^ (x >> 4)) & 0x0F;
+    return (0x6996 >> x) & 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the parity of a 32 bit word.
+    \param x The word to be checked.
+    \return 1 for odd, or 0 for even. */
+static __inline__ int parity32(uint32_t x)
+{
+    x ^= (x >> 16);
+    x ^= (x >> 8);
+    x = (x ^ (x >> 4)) & 0x0F;
+    return (0x6996 >> x) & 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/

drivers/staging/echo/echo.c

···
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * echo.c - A line echo canceller.  This code is being developed
+ *          against and partially complies with G168.
+ *
+ * Written by Steve Underwood <[e-mail]>
+ *         and David Rowe <david_at_rowetel_dot_com>
+ *
+ * Copyright (C) 2001, 2003 Steve Underwood, 2007 David Rowe
+ *
+ * Based on a bit from here, a bit from there, eye of toad, ear of
+ * bat, 15 years of failed attempts by David and a few fried brain
+ * cells.
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: echo.c,v 1.20 2006/12/01 18:00:48 steveu Exp $
+ */
+
+/*! \file */
+
+/* Implementation Notes
+   David Rowe
+   April 2007
+
+   This code started life as Steve's NLMS algorithm with a tap
+   rotation algorithm to handle divergence during double talk.  I
+   added a Geigel Double Talk Detector (DTD) [2] and performed some
+   G168 tests.  However I had trouble meeting the G168 requirements,
+   especially for double talk - there were always cases where my DTD
+   failed, for example where near end speech was under the 6dB
+   threshold required for declaring double talk.
+
+   So I tried a two path algorithm [1], which has so far given better
+   results.  The original tap rotation/Geigel algorithm is available
+   in SVN http://svn.rowetel.com/software/oslec/tags/before_16bit.
+   It's probably possible to make it work if some one wants to put some
+   serious work into it.
+
+   At present no special treatment is provided for tones, which
+   generally cause NLMS algorithms to diverge.  Initial runs of a
+   subset of the G168 tests for tones (e.g ./echo_test 6) show the
+   current algorithm is passing OK, which is kind of surprising.  The
+   full set of tests needs to be performed to confirm this result.
+
+   One other interesting change is that I have managed to get the NLMS
+   code to work with 16 bit coefficients, rather than the original 32
+   bit coefficents.  This reduces the MIPs and storage required.
+   I evaulated the 16 bit port using g168_tests.sh and listening tests
+   on 4 real-world samples.
+
+   I also attempted the implementation of a block based NLMS update
+   [2] but although this passes g168_tests.sh it didn't converge well
+   on the real-world samples.  I have no idea why, perhaps a scaling
+   problem.  The block based code is also available in SVN
+   http://svn.rowetel.com/software/oslec/tags/before_16bit.  If this
+   code can be debugged, it will lead to further reduction in MIPS, as
+   the block update code maps nicely onto DSP instruction sets (it's a
+   dot product) compared to the current sample-by-sample update.
+
+   Steve also has some nice notes on echo cancellers in echo.h
+
+
+   References:
+
+   [1] Ochiai, Areseki, and Ogihara, "Echo Canceller with Two Echo
+       Path Models", IEEE Transactions on communications, COM-25,
+       No. 6, June
+       1977.
+       http://www.rowetel.com/images/echo/dual_path_paper.pdf
+
+   [2] The classic, very useful paper that tells you how to
+       actually build a real world echo canceller:
+         Messerschmitt, Hedberg, Cole, Haoui, Winship, "Digital Voice
+         Echo Canceller with a TMS320020,
+         http://www.rowetel.com/images/echo/spra129.pdf
+
+   [3] I have written a series of blog posts on this work, here is
+       Part 1: http://www.rowetel.com/blog/?p=18
+
+   [4] The source code http://svn.rowetel.com/software/oslec/
+
+   [5] A nice reference on LMS filters:
+         http://en.wikipedia.org/wiki/Least_mean_squares_filter
+
+   Credits:
+
+   Thanks to Steve Underwood, Jean-Marc Valin, and Ramakrishnan
+   Muthukrishnan for their suggestions and email discussions.  Thanks
+   also to those people who collected echo samples for me such as
+   Mark, Pawel, and Pavel.
+*/
+
+#include <linux/kernel.h>       /* We're doing kernel work */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#define malloc(a) kmalloc((a), GFP_KERNEL)
+#define free(a) kfree(a)
+
+#include "bit_operations.h"
+#include "echo.h"
+
+#define MIN_TX_POWER_FOR_ADAPTION   64
+#define MIN_RX_POWER_FOR_ADAPTION   64
+#define DTD_HANGOVER               600     /* 600 samples, or 75ms     */
+#define DC_LOG2BETA                  3     /* log2() of DC filter Beta */
+
+/*-----------------------------------------------------------------------*\
+                               FUNCTIONS
+\*-----------------------------------------------------------------------*/
+
+/* adapting coeffs using the traditional stochastic descent (N)LMS algorithm */
+
+
+#ifdef __BLACKFIN_ASM__
+static void __inline__ lms_adapt_bg(echo_can_state_t *ec, int clean, int shift)
+{
+    int i, j;
+    int offset1;
+    int offset2;
+    int factor;
+    int exp;
+    int16_t *phist;
+    int n;
+
+    if (shift > 0)
+	factor = clean << shift;
+    else
+	factor = clean >> -shift;
+
+    /* Update the FIR taps */
+
+    offset2 = ec->curr_pos;
+    offset1 = ec->taps - offset2;
+    phist = &ec->fir_state_bg.history[offset2];
+
+    /* st: and en: help us locate the assembler in echo.s */
+
+    //asm("st:");
+    n = ec->taps;
+    for (i = 0, j = offset2;  i < n;  i++, j++)
+    {
+       exp = *phist++ * factor;
+       ec->fir_taps16[1][i] += (int16_t) ((exp+(1<<14)) >> 15);
+    }
+    //asm("en:");
+
+    /* Note the asm for the inner loop above generated by Blackfin gcc
+       4.1.1 is pretty good (note even parallel instructions used):
+
+    	R0 = W [P0++] (X);
+	R0 *= R2;
+	R0 = R0 + R3 (NS) ||
+	R1 = W [P1] (X) ||
+	nop;
+	R0 >>>= 15;
+	R0 = R0 + R1;
+	W [P1++] = R0;
+
+	A block based update algorithm would be much faster but the
+	above can't be improved on much.  Every instruction saved in
+	the loop above is 2 MIPs/ch!  The for loop above is where the
+	Blackfin spends most of it's time - about 17 MIPs/ch measured
+	with speedtest.c with 256 taps (32ms).  Write-back and
+	Write-through cache gave about the same performance.
+    */
+}
+
+/*
+   IDEAS for further optimisation of lms_adapt_bg():
+
+   1/ The rounding is quite costly.  Could we keep as 32 bit coeffs
+   then make filter pluck the MS 16-bits of the coeffs when filtering?
+   However this would lower potential optimisation of filter, as I
+   think the dual-MAC architecture requires packed 16 bit coeffs.
+
+   2/ Block based update would be more efficient, as per comments above,
+   could use dual MAC architecture.
+
+   3/ Look for same sample Blackfin LMS code, see if we can get dual-MAC
+   packing.
+
+   4/ Execute the whole e/c in a block of say 20ms rather than sample
+   by sample.  Processing a few samples every ms is inefficient.
+*/
+
+#else
+static __inline__ void lms_adapt_bg(echo_can_state_t *ec, int clean, int shift)
+{
+    int i;
+
+    int offset1;
+    int offset2;
+    int factor;
+    int exp;
+
+    if (shift > 0)
+	factor = clean << shift;
+    else
+	factor = clean >> -shift;
+
+    /* Update the FIR taps */
+
+    offset2 = ec->curr_pos;
+    offset1 = ec->taps - offset2;
+
+    for (i = ec->taps - 1;  i >= offset1;  i--)
+    {
+       exp = (ec->fir_state_bg.history[i - offset1]*factor);
+       ec->fir_taps16[1][i] += (int16_t) ((exp+(1<<14)) >> 15);
+    }
+    for (  ;  i >= 0;  i--)
+    {
+       exp = (ec->fir_state_bg.history[i + offset2]*factor);
+       ec->fir_taps16[1][i] += (int16_t) ((exp+(1<<14)) >> 15);
+    }
+}
+#endif
+
+/*- End of function --------------------------------------------------------*/
+
+echo_can_state_t *echo_can_create(int len, int adaption_mode)
+{
+    echo_can_state_t *ec;
+    int i;
+    int j;
+
+    ec = kmalloc(sizeof(*ec), GFP_KERNEL);
+    if (ec == NULL)
+        return  NULL;
+    memset(ec, 0, sizeof(*ec));
+
+    ec->taps = len;
+    ec->log2taps = top_bit(len);
+    ec->curr_pos = ec->taps - 1;
+
+    for (i = 0;  i < 2;  i++)
+    {
+        if ((ec->fir_taps16[i] = (int16_t *) malloc((ec->taps)*sizeof(int16_t))) == NULL)
+        {
+            for (j = 0;  j < i;  j++)
+                kfree(ec->fir_taps16[j]);
+            kfree(ec);
+            return  NULL;
+        }
+        memset(ec->fir_taps16[i], 0, (ec->taps)*sizeof(int16_t));
+    }
+
+    fir16_create(&ec->fir_state,
+                 ec->fir_taps16[0],
+                 ec->taps);
+    fir16_create(&ec->fir_state_bg,
+                 ec->fir_taps16[1],
+                 ec->taps);
+
+    for(i=0; i<5; i++) {
+      ec->xvtx[i] = ec->yvtx[i] = ec->xvrx[i] = ec->yvrx[i] = 0;
+    }
+
+    ec->cng_level = 1000;
+    echo_can_adaption_mode(ec, adaption_mode);
+
+    ec->snapshot = (int16_t*)malloc(ec->taps*sizeof(int16_t));
+    memset(ec->snapshot, 0, sizeof(int16_t)*ec->taps);
+
+    ec->cond_met = 0;
+    ec->Pstates = 0;
+    ec->Ltxacc = ec->Lrxacc = ec->Lcleanacc = ec->Lclean_bgacc = 0;
+    ec->Ltx = ec->Lrx = ec->Lclean = ec->Lclean_bg = 0;
+    ec->tx_1 = ec->tx_2 = ec->rx_1 = ec->rx_2 = 0;
+    ec->Lbgn = ec->Lbgn_acc = 0;
+    ec->Lbgn_upper = 200;
+    ec->Lbgn_upper_acc = ec->Lbgn_upper << 13;
+
+    return  ec;
+}
+/*- End of function --------------------------------------------------------*/
+
+void echo_can_free(echo_can_state_t *ec)
+{
+	int i;
+
+	fir16_free(&ec->fir_state);
+	fir16_free(&ec->fir_state_bg);
+	for (i = 0;  i < 2;  i++)
+		kfree(ec->fir_taps16[i]);
+	kfree(ec->snapshot);
+	kfree(ec);
+}
+/*- End of function --------------------------------------------------------*/
+
+void echo_can_adaption_mode(echo_can_state_t *ec, int adaption_mode)
+{
+    ec->adaption_mode = adaption_mode;
+}
+/*- End of function --------------------------------------------------------*/
+
+void echo_can_flush(echo_can_state_t *ec)
+{
+    int i;
+
+    ec->Ltxacc = ec->Lrxacc = ec->Lcleanacc = ec->Lclean_bgacc = 0;
+    ec->Ltx = ec->Lrx = ec->Lclean = ec->Lclean_bg = 0;
+    ec->tx_1 = ec->tx_2 = ec->rx_1 = ec->rx_2 = 0;
+
+    ec->Lbgn = ec->Lbgn_acc = 0;
+    ec->Lbgn_upper = 200;
+    ec->Lbgn_upper_acc = ec->Lbgn_upper << 13;
+
+    ec->nonupdate_dwell = 0;
+
+    fir16_flush(&ec->fir_state);
+    fir16_flush(&ec->fir_state_bg);
+    ec->fir_state.curr_pos = ec->taps - 1;
+    ec->fir_state_bg.curr_pos = ec->taps - 1;
+    for (i = 0;  i < 2;  i++)
+        memset(ec->fir_taps16[i], 0, ec->taps*sizeof(int16_t));
+
+    ec->curr_pos = ec->taps - 1;
+    ec->Pstates = 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+void echo_can_snapshot(echo_can_state_t *ec) {
+    memcpy(ec->snapshot, ec->fir_taps16[0], ec->taps*sizeof(int16_t));
+}
+/*- End of function --------------------------------------------------------*/
+
+/* Dual Path Echo Canceller ------------------------------------------------*/
+
+int16_t echo_can_update(echo_can_state_t *ec, int16_t tx, int16_t rx)
+{
+    int32_t echo_value;
+    int clean_bg;
+    int tmp, tmp1;
+
+    /* Input scaling was found be required to prevent problems when tx
+       starts clipping.  Another possible way to handle this would be the
+       filter coefficent scaling. */
+
+    ec->tx = tx; ec->rx = rx;
+    tx >>=1;
+    rx >>=1;
+
+    /*
+       Filter DC, 3dB point is 160Hz (I think), note 32 bit precision required
+       otherwise values do not track down to 0. Zero at DC, Pole at (1-Beta)
+       only real axis.  Some chip sets (like Si labs) don't need
+       this, but something like a $10 X100P card does.  Any DC really slows
+       down convergence.
+
+       Note: removes some low frequency from the signal, this reduces
+       the speech quality when listening to samples through headphones
+       but may not be obvious through a telephone handset.
+
+       Note that the 3dB frequency in radians is approx Beta, e.g. for
+       Beta = 2^(-3) = 0.125, 3dB freq is 0.125 rads = 159Hz.
+    */
+
+    if (ec->adaption_mode & ECHO_CAN_USE_RX_HPF) {
+      tmp = rx << 15;
+#if 1
+        /* Make sure the gain of the HPF is 1.0. This can still saturate a little under
+           impulse conditions, and it might roll to 32768 and need clipping on sustained peak
+           level signals. However, the scale of such clipping is small, and the error due to
+           any saturation should not markedly affect the downstream processing. */
+        tmp -= (tmp >> 4);
+#endif
+      ec->rx_1 += -(ec->rx_1>>DC_LOG2BETA) + tmp - ec->rx_2;
+
+      /* hard limit filter to prevent clipping.  Note that at this stage
+	 rx should be limited to +/- 16383 due to right shift above */
+      tmp1 = ec->rx_1 >> 15;
+      if (tmp1 > 16383) tmp1 = 16383;
+      if (tmp1 < -16383) tmp1 = -16383;
+      rx = tmp1;
+      ec->rx_2 = tmp;
+    }
+
+    /* Block average of power in the filter states.  Used for
+       adaption power calculation. */
+
+    {
+	int new, old;
+
+	/* efficient "out with the old and in with the new" algorithm so
+	   we don't have to recalculate over the whole block of
+	   samples. */
+	new = (int)tx * (int)tx;
+	old = (int)ec->fir_state.history[ec->fir_state.curr_pos] *
+              (int)ec->fir_state.history[ec->fir_state.curr_pos];
+	ec->Pstates += ((new - old) + (1<<ec->log2taps)) >> ec->log2taps;
+	if (ec->Pstates < 0) ec->Pstates = 0;
+    }
+
+    /* Calculate short term average levels using simple single pole IIRs */
+
+    ec->Ltxacc += abs(tx) - ec->Ltx;
+    ec->Ltx = (ec->Ltxacc + (1<<4)) >> 5;
+    ec->Lrxacc += abs(rx) - ec->Lrx;
+    ec->Lrx = (ec->Lrxacc + (1<<4)) >> 5;
+
+    /* Foreground filter ---------------------------------------------------*/
+
+    ec->fir_state.coeffs = ec->fir_taps16[0];
+    echo_value = fir16(&ec->fir_state, tx);
+    ec->clean = rx - echo_value;
+    ec->Lcleanacc += abs(ec->clean) - ec->Lclean;
+    ec->Lclean = (ec->Lcleanacc + (1<<4)) >> 5;
+
+    /* Background filter ---------------------------------------------------*/
+
+    echo_value = fir16(&ec->fir_state_bg, tx);
+    clean_bg = rx - echo_value;
+    ec->Lclean_bgacc += abs(clean_bg) - ec->Lclean_bg;
+    ec->Lclean_bg = (ec->Lclean_bgacc + (1<<4)) >> 5;
+
+    /* Background Filter adaption -----------------------------------------*/
+
+    /* Almost always adap bg filter, just simple DT and energy
+       detection to minimise adaption in cases of strong double talk.
+       However this is not critical for the dual path algorithm.
+    */
+    ec->factor = 0;
+    ec->shift = 0;
+    if ((ec->nonupdate_dwell == 0)) {
+	int   P, logP, shift;
+
+	/* Determine:
+
+	   f = Beta * clean_bg_rx/P ------ (1)
+
+	   where P is the total power in the filter states.
+
+	   The Boffins have shown that if we obey (1) we converge
+	   quickly and avoid instability.
+
+	   The correct factor f must be in Q30, as this is the fixed
+	   point format required by the lms_adapt_bg() function,
+	   therefore the scaled version of (1) is:
+
+	   (2^30) * f  = (2^30) * Beta * clean_bg_rx/P
+	       factor  = (2^30) * Beta * clean_bg_rx/P         ----- (2)
+
+	   We have chosen Beta = 0.25 by experiment, so:
+
+	       factor  = (2^30) * (2^-2) * clean_bg_rx/P
+
+                                       (30 - 2 - log2(P))
+	       factor  = clean_bg_rx 2                         ----- (3)
+
+	   To avoid a divide we approximate log2(P) as top_bit(P),
+	   which returns the position of the highest non-zero bit in
+	   P.  This approximation introduces an error as large as a
+	   factor of 2, but the algorithm seems to handle it OK.
+
+	   Come to think of it a divide may not be a big deal on a
+	   modern DSP, so its probably worth checking out the cycles
+	   for a divide versus a top_bit() implementation.
+	*/
+
+	P = MIN_TX_POWER_FOR_ADAPTION + ec->Pstates;
+	logP = top_bit(P) + ec->log2taps;
+	shift = 30 - 2 - logP;
+	ec->shift = shift;
+
+	lms_adapt_bg(ec, clean_bg, shift);
+    }
+
+    /* very simple DTD to make sure we dont try and adapt with strong
+       near end speech */
+
+    ec->adapt = 0;
+    if ((ec->Lrx > MIN_RX_POWER_FOR_ADAPTION) && (ec->Lrx > ec->Ltx))
+	ec->nonupdate_dwell = DTD_HANGOVER;
+    if (ec->nonupdate_dwell)
+	ec->nonupdate_dwell--;
+
+    /* Transfer logic ------------------------------------------------------*/
+
+    /* These conditions are from the dual path paper [1], I messed with
+       them a bit to improve performance. */
+
+    if ((ec->adaption_mode & ECHO_CAN_USE_ADAPTION) &&
+	(ec->nonupdate_dwell == 0) &&
+	(8*ec->Lclean_bg < 7*ec->Lclean) /* (ec->Lclean_bg < 0.875*ec->Lclean) */ &&
+	(8*ec->Lclean_bg < ec->Ltx)      /* (ec->Lclean_bg < 0.125*ec->Ltx)    */ )
+    {
+	if (ec->cond_met == 6) {
+	    /* BG filter has had better results for 6 consecutive samples */
+	    ec->adapt = 1;
+	    memcpy(ec->fir_taps16[0], ec->fir_taps16[1], ec->taps*sizeof(int16_t));
+	}
+	else
+	    ec->cond_met++;
+    }
+    else
+	ec->cond_met = 0;
+
+    /* Non-Linear Processing ---------------------------------------------------*/
+
+    ec->clean_nlp = ec->clean;
+    if (ec->adaption_mode & ECHO_CAN_USE_NLP)
+    {
+        /* Non-linear processor - a fancy way to say "zap small signals, to avoid
+           residual echo due to (uLaw/ALaw) non-linearity in the channel.". */
+
+      if ((16*ec->Lclean < ec->Ltx))
+      {
+	/* Our e/c has improved echo by at least 24 dB (each factor of 2 is 6dB,
+	   so 2*2*2*2=16 is the same as 6+6+6+6=24dB) */
+        if (ec->adaption_mode & ECHO_CAN_USE_CNG)
+	{
+	    ec->cng_level = ec->Lbgn;
+
+	    /* Very elementary comfort noise generation.  Just random
+	       numbers rolled off very vaguely Hoth-like.  DR: This
+	       noise doesn't sound quite right to me - I suspect there
+	       are some overlfow issues in the filtering as it's too
+	       "crackly".  TODO: debug this, maybe just play noise at
+	       high level or look at spectrum.
+	    */
+
+	    ec->cng_rndnum = 1664525U*ec->cng_rndnum + 1013904223U;
+	    ec->cng_filter = ((ec->cng_rndnum & 0xFFFF) - 32768 + 5*ec->cng_filter) >> 3;
+	    ec->clean_nlp = (ec->cng_filter*ec->cng_level*8) >> 14;
+
+        }
+        else if (ec->adaption_mode & ECHO_CAN_USE_CLIP)
+	{
+	    /* This sounds much better than CNG */
+	    if (ec->clean_nlp > ec->Lbgn)
+	      ec->clean_nlp = ec->Lbgn;
+	    if (ec->clean_nlp < -ec->Lbgn)
+	      ec->clean_nlp = -ec->Lbgn;
+	}
+	else
+        {
+	  /* just mute the residual, doesn't sound very good, used mainly
+	     in G168 tests */
+          ec->clean_nlp = 0;
+        }
+      }
+      else {
+	  /* Background noise estimator.  I tried a few algorithms
+	     here without much luck.  This very simple one seems to
+	     work best, we just average the level using a slow (1 sec
+	     time const) filter if the current level is less than a
+	     (experimentally derived) constant.  This means we dont
+	     include high level signals like near end speech.  When
+	     combined with CNG or especially CLIP seems to work OK.
+	  */
+	  if (ec->Lclean < 40) {
+	      ec->Lbgn_acc += abs(ec->clean) - ec->Lbgn;
+	      ec->Lbgn = (ec->Lbgn_acc + (1<<11)) >> 12;
+	  }
+       }
+    }
+
+    /* Roll around the taps buffer */
+    if (ec->curr_pos <= 0)
+        ec->curr_pos = ec->taps;
+    ec->curr_pos--;
+
+    if (ec->adaption_mode & ECHO_CAN_DISABLE)
+      ec->clean_nlp = rx;
+
+    /* Output scaled back up again to match input scaling */
+
+    return (int16_t) ec->clean_nlp << 1;
+}
+
+/*- End of function --------------------------------------------------------*/
+
+/* This function is seperated from the echo canceller is it is usually called
+   as part of the tx process.  See rx HP (DC blocking) filter above, it's
+   the same design.
+
+   Some soft phones send speech signals with a lot of low frequency
+   energy, e.g. down to 20Hz.  This can make the hybrid non-linear
+   which causes the echo canceller to fall over.  This filter can help
+   by removing any low frequency before it gets to the tx port of the
+   hybrid.
+
+   It can also help by removing and DC in the tx signal.  DC is bad
+   for LMS algorithms.
+
+   This is one of the classic DC removal filters, adjusted to provide sufficient
+   bass rolloff to meet the above requirement to protect hybrids from things that
+   upset them. The difference between successive samples produces a lousy HPF, and
+   then a suitably placed pole flattens things out. The final result is a nicely
+   rolled off bass end. The filtering is implemented with extended fractional
+   precision, which noise shapes things, giving very clean DC removal.
+*/
+
+int16_t echo_can_hpf_tx(echo_can_state_t *ec, int16_t tx) {
+    int tmp, tmp1;
+
+    if (ec->adaption_mode & ECHO_CAN_USE_TX_HPF) {
+        tmp = tx << 15;
+#if 1
+        /* Make sure the gain of the HPF is 1.0. The first can still saturate a little under
+           impulse conditions, and it might roll to 32768 and need clipping on sustained peak
+           level signals. However, the scale of such clipping is small, and the error due to
+           any saturation should not markedly affect the downstream processing. */
+        tmp -= (tmp >> 4);
+#endif
+        ec->tx_1 += -(ec->tx_1>>DC_LOG2BETA) + tmp - ec->tx_2;
+        tmp1 = ec->tx_1 >> 15;
+	if (tmp1 > 32767) tmp1 = 32767;
+	if (tmp1 < -32767) tmp1 = -32767;
+	tx = tmp1;
+        ec->tx_2 = tmp;
+    }
+
+    return tx;
+}

drivers/staging/echo/echo.h

···
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * echo.c - A line echo canceller.  This code is being developed
+ *          against and partially complies with G168.
+ *
+ * Written by Steve Underwood <[e-mail]>
+ *         and David Rowe <david_at_rowetel_dot_com>
+ *
+ * Copyright (C) 2001 Steve Underwood and 2007 David Rowe
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: echo.h,v 1.9 2006/10/24 13:45:28 steveu Exp $
+ */
+
+#ifndef __ECHO_H
+#define __ECHO_H
+
+/*! \page echo_can_page Line echo cancellation for voice
+
+\section echo_can_page_sec_1 What does it do?
+This module aims to provide G.168-2002 compliant echo cancellation, to remove
+electrical echoes (e.g. from 2-4 wire hybrids) from voice calls.
+
+\section echo_can_page_sec_2 How does it work?
+The heart of the echo cancellor is FIR filter. This is adapted to match the
+echo impulse response of the telephone line. It must be long enough to
+adequately cover the duration of that impulse response. The signal transmitted
+to the telephone line is passed through the FIR filter. Once the FIR is
+properly adapted, the resulting output is an estimate of the echo signal
+received from the line. This is subtracted from the received signal. The result
+is an estimate of the signal which originated at the far end of the line, free
+from echos of our own transmitted signal.
+
+The least mean squares (LMS) algorithm is attributed to Widrow and Hoff, and
+was introduced in 1960. It is the commonest form of filter adaption used in
+things like modem line equalisers and line echo cancellers. There it works very
+well.  However, it only works well for signals of constant amplitude. It works
+very poorly for things like speech echo cancellation, where the signal level
+varies widely.  This is quite easy to fix. If the signal level is normalised -
+similar to applying AGC - LMS can work as well for a signal of varying
+amplitude as it does for a modem signal. This normalised least mean squares
+(NLMS) algorithm is the commonest one used for speech echo cancellation. Many
+other algorithms exist - e.g. RLS (essentially the same as Kalman filtering),
+FAP, etc. Some perform significantly better than NLMS.  However, factors such
+as computational complexity and patents favour the use of NLMS.
+
+A simple refinement to NLMS can improve its performance with speech. NLMS tends
+to adapt best to the strongest parts of a signal. If the signal is white noise,
+the NLMS algorithm works very well. However, speech has more low frequency than
+high frequency content. Pre-whitening (i.e. filtering the signal to flatten its
+spectrum) the echo signal improves the adapt rate for speech, and ensures the
+final residual signal is not heavily biased towards high frequencies. A very
+low complexity filter is adequate for this, so pre-whitening adds little to the
+compute requirements of the echo canceller.
+
+An FIR filter adapted using pre-whitened NLMS performs well, provided certain
+conditions are met:
+
+    - The transmitted signal has poor self-correlation.
+    - There is no signal being generated within the environment being
+      cancelled.
+
+The difficulty is that neither of these can be guaranteed.
+
+If the adaption is performed while transmitting noise (or something fairly
+noise like, such as voice) the adaption works very well. If the adaption is
+performed while transmitting something highly correlative (typically narrow
+band energy such as signalling tones or DTMF), the adaption can go seriously
+wrong. The reason is there is only one solution for the adaption on a near
+random signal - the impulse response of the line. For a repetitive signal,
+there are any number of solutions which converge the adaption, and nothing
+guides the adaption to choose the generalised one. Allowing an untrained
+canceller to converge on this kind of narrowband energy probably a good thing,
+since at least it cancels the tones. Allowing a well converged canceller to
+continue converging on such energy is just a way to ruin its generalised
+adaption. A narrowband detector is needed, so adapation can be suspended at
+appropriate times.
+
+The adaption process is based on trying to eliminate the received signal. When
+there is any signal from within the environment being cancelled it may upset
+the adaption process. Similarly, if the signal we are transmitting is small,
+noise may dominate and disturb the adaption process. If we can ensure that the
+adaption is only performed when we are transmitting a significant signal level,
+and the environment is not, things will be OK. Clearly, it is easy to tell when
+we are sending a significant signal. Telling, if the environment is generating
+a significant signal, and doing it with sufficient speed that the adaption will
+not have diverged too much more we stop it, is a little harder.
+
+The key problem in detecting when the environment is sourcing significant
+energy is that we must do this very quickly. Given a reasonably long sample of
+the received signal, there are a number of strategies which may be used to
+assess whether that signal contains a strong far end component. However, by the
+time that assessment is complete the far end signal will have already caused
+major mis-convergence in the adaption process. An assessment algorithm is
+needed which produces a fairly accurate result from a very short burst of far
+end energy.
+
+\section echo_can_page_sec_3 How do I use it?
+The echo cancellor processes both the transmit and receive streams sample by
+sample. The processing function is not declared inline. Unfortunately,
+cancellation requires many operations per sample, so the call overhead is only
+a minor burden.
+*/
+
+#include "fir.h"
+
+/* Mask bits for the adaption mode */
+#define ECHO_CAN_USE_ADAPTION	0x01
+#define ECHO_CAN_USE_NLP	0x02
+#define ECHO_CAN_USE_CNG	0x04
+#define ECHO_CAN_USE_CLIP	0x08
+#define ECHO_CAN_USE_TX_HPF	0x10
+#define ECHO_CAN_USE_RX_HPF	0x20
+#define ECHO_CAN_DISABLE	0x40
+
+/*!
+    G.168 echo canceller descriptor. This defines the working state for a line
+    echo canceller.
+*/
+typedef struct
+{
+	int16_t tx,rx;
+	int16_t clean;
+	int16_t clean_nlp;
+
+	int nonupdate_dwell;
+	int curr_pos;
+	int taps;
+	int log2taps;
+	int adaption_mode;
+
+	int cond_met;
+	int32_t Pstates;
+	int16_t adapt;
+	int32_t factor;
+	int16_t shift;
+
+	/* Average levels and averaging filter states */
+	int Ltxacc, Lrxacc, Lcleanacc, Lclean_bgacc;
+	int Ltx, Lrx;
+	int Lclean;
+	int Lclean_bg;
+	int Lbgn, Lbgn_acc, Lbgn_upper, Lbgn_upper_acc;
+
+	/* foreground and background filter states */
+	fir16_state_t fir_state;
+	fir16_state_t fir_state_bg;
+	int16_t *fir_taps16[2];
+
+	/* DC blocking filter states */
+	int tx_1, tx_2, rx_1, rx_2;
+
+	/* optional High Pass Filter states */
+	int32_t xvtx[5], yvtx[5];
+	int32_t xvrx[5], yvrx[5];
+
+	/* Parameters for the optional Hoth noise generator */
+	int cng_level;
+	int cng_rndnum;
+	int cng_filter;
+
+	/* snapshot sample of coeffs used for development */
+	int16_t *snapshot;
+} echo_can_state_t;
+
+/*! Create a voice echo canceller context.
+    \param len The length of the canceller, in samples.
+    \return The new canceller context, or NULL if the canceller could not be created.
+*/
+echo_can_state_t *echo_can_create(int len, int adaption_mode);
+
+/*! Free a voice echo canceller context.
+    \param ec The echo canceller context.
+*/
+void echo_can_free(echo_can_state_t *ec);
+
+/*! Flush (reinitialise) a voice echo canceller context.
+    \param ec The echo canceller context.
+*/
+void echo_can_flush(echo_can_state_t *ec);
+
+/*! Set the adaption mode of a voice echo canceller context.
+    \param ec The echo canceller context.
+    \param adapt The mode.
+*/
+void echo_can_adaption_mode(echo_can_state_t *ec, int adaption_mode);
+
+void echo_can_snapshot(echo_can_state_t *ec);
+
+/*! Process a sample through a voice echo canceller.
+    \param ec The echo canceller context.
+    \param tx The transmitted audio sample.
+    \param rx The received audio sample.
+    \return The clean (echo cancelled) received sample.
+*/
+int16_t echo_can_update(echo_can_state_t *ec, int16_t tx, int16_t rx);
+
+/*! Process to high pass filter the tx signal.
+    \param ec The echo canceller context.
+    \param tx The transmitted auio sample.
+    \return The HP filtered transmit sample, send this to your D/A.
+*/
+int16_t echo_can_hpf_tx(echo_can_state_t *ec, int16_t tx);
+
+#endif	/* __ECHO_H */

drivers/staging/echo/fir.h

···
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * fir.h - General telephony FIR routines
+ *
+ * Written by Steve Underwood <[e-mail]>
+ *
+ * Copyright (C) 2002 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: fir.h,v 1.8 2006/10/24 13:45:28 steveu Exp $
+ */
+
+/*! \page fir_page FIR filtering
+\section fir_page_sec_1 What does it do?
+???.
+
+\section fir_page_sec_2 How does it work?
+???.
+*/
+
+#if !defined(_FIR_H_)
+#define _FIR_H_
+
+/*
+   Blackfin NOTES & IDEAS:
+
+   A simple dot product function is used to implement the filter.  This performs
+   just one MAC/cycle which is inefficient but was easy to implement as a first
+   pass.  The current Blackfin code also uses an unrolled form of the filter
+   history to avoid 0 length hardware loop issues.  This is wasteful of
+   memory.
+
+   Ideas for improvement:
+
+   1/ Rewrite filter for dual MAC inner loop.  The issue here is handling
+   history sample offsets that are 16 bit aligned - the dual MAC needs
+   32 bit aligmnent.  There are some good examples in libbfdsp.
+
+   2/ Use the hardware circular buffer facility tohalve memory usage.
+
+   3/ Consider using internal memory.
+
+   Using less memory might also improve speed as cache misses will be
+   reduced. A drop in MIPs and memory approaching 50% should be
+   possible.
+
+   The foreground and background filters currenlty use a total of
+   about 10 MIPs/ch as measured with speedtest.c on a 256 TAP echo
+   can.
+*/
+
+#if defined(USE_MMX)  ||  defined(USE_SSE2)
+#include "mmx.h"
+#endif
+
+/*!
+    16 bit integer FIR descriptor. This defines the working state for a single
+    instance of an FIR filter using 16 bit integer coefficients.
+*/
+typedef struct
+{
+	int taps;
+	int curr_pos;
+	const int16_t *coeffs;
+	int16_t *history;
+} fir16_state_t;
+
+/*!
+    32 bit integer FIR descriptor. This defines the working state for a single
+    instance of an FIR filter using 32 bit integer coefficients, and filtering
+    16 bit integer data.
+*/
+typedef struct
+{
+	int taps;
+	int curr_pos;
+	const int32_t *coeffs;
+	int16_t *history;
+} fir32_state_t;
+
+/*!
+    Floating point FIR descriptor. This defines the working state for a single
+    instance of an FIR filter using floating point coefficients and data.
+*/
+typedef struct
+{
+	int taps;
+	int curr_pos;
+	const float *coeffs;
+	float *history;
+} fir_float_state_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static __inline__ const int16_t *fir16_create(fir16_state_t *fir,
+                                              const int16_t *coeffs,
+                                              int taps)
+{
+	fir->taps = taps;
+	fir->curr_pos = taps - 1;
+	fir->coeffs = coeffs;
+#if defined(USE_MMX)  ||  defined(USE_SSE2) || defined(__BLACKFIN_ASM__)
+	if ((fir->history = malloc(2*taps*sizeof(int16_t))))
+		memset(fir->history, 0, 2*taps*sizeof(int16_t));
+#else
+	if ((fir->history = (int16_t *) malloc(taps*sizeof(int16_t))))
+		memset(fir->history, 0, taps*sizeof(int16_t));
+#endif
+	return fir->history;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ void fir16_flush(fir16_state_t *fir)
+{
+#if defined(USE_MMX)  ||  defined(USE_SSE2) || defined(__BLACKFIN_ASM__)
+    memset(fir->history, 0, 2*fir->taps*sizeof(int16_t));
+#else
+    memset(fir->history, 0, fir->taps*sizeof(int16_t));
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ void fir16_free(fir16_state_t *fir)
+{
+	free(fir->history);
+}
+/*- End of function --------------------------------------------------------*/
+
+#ifdef __BLACKFIN_ASM__
+static inline int32_t dot_asm(short *x, short *y, int len)
+{
+   int dot;
+
+   len--;
+
+   __asm__
+   (
+   "I0 = %1;\n\t"
+   "I1 = %2;\n\t"
+   "A0 = 0;\n\t"
+   "R0.L = W[I0++] || R1.L = W[I1++];\n\t"
+   "LOOP dot%= LC0 = %3;\n\t"
+   "LOOP_BEGIN dot%=;\n\t"
+      "A0 += R0.L * R1.L (IS) || R0.L = W[I0++] || R1.L = W[I1++];\n\t"
+   "LOOP_END dot%=;\n\t"
+   "A0 += R0.L*R1.L (IS);\n\t"
+   "R0 = A0;\n\t"
+   "%0 = R0;\n\t"
+   : "=&d" (dot)
+   : "a" (x), "a" (y), "a" (len)
+   : "I0", "I1", "A1", "A0", "R0", "R1"
+   );
+
+   return dot;
+}
+#endif
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t fir16(fir16_state_t *fir, int16_t sample)
+{
+    int32_t y;
+#if defined(USE_MMX)
+    int i;
+    mmx_t *mmx_coeffs;
+    mmx_t *mmx_hist;
+
+    fir->history[fir->curr_pos] = sample;
+    fir->history[fir->curr_pos + fir->taps] = sample;
+
+    mmx_coeffs = (mmx_t *) fir->coeffs;
+    mmx_hist = (mmx_t *) &fir->history[fir->curr_pos];
+    i = fir->taps;
+    pxor_r2r(mm4, mm4);
+    /* 8 samples per iteration, so the filter must be a multiple of 8 long. */
+    while (i > 0)
+    {
+        movq_m2r(mmx_coeffs[0], mm0);
+        movq_m2r(mmx_coeffs[1], mm2);
+        movq_m2r(mmx_hist[0], mm1);
+        movq_m2r(mmx_hist[1], mm3);
+        mmx_coeffs += 2;
+        mmx_hist += 2;
+        pmaddwd_r2r(mm1, mm0);
+        pmaddwd_r2r(mm3, mm2);
+        paddd_r2r(mm0, mm4);
+        paddd_r2r(mm2, mm4);
+        i -= 8;
+    }
+    movq_r2r(mm4, mm0);
+    psrlq_i2r(32, mm0);
+    paddd_r2r(mm0, mm4);
+    movd_r2m(mm4, y);
+    emms();
+#elif defined(USE_SSE2)
+    int i;
+    xmm_t *xmm_coeffs;
+    xmm_t *xmm_hist;
+
+    fir->history[fir->curr_pos] = sample;
+    fir->history[fir->curr_pos + fir->taps] = sample;
+
+    xmm_coeffs = (xmm_t *) fir->coeffs;
+    xmm_hist = (xmm_t *) &fir->history[fir->curr_pos];
+    i = fir->taps;
+    pxor_r2r(xmm4, xmm4);
+    /* 16 samples per iteration, so the filter must be a multiple of 16 long. */
+    while (i > 0)
+    {
+        movdqu_m2r(xmm_coeffs[0], xmm0);
+        movdqu_m2r(xmm_coeffs[1], xmm2);
+        movdqu_m2r(xmm_hist[0], xmm1);
+        movdqu_m2r(xmm_hist[1], xmm3);
+        xmm_coeffs += 2;
+        xmm_hist += 2;
+        pmaddwd_r2r(xmm1, xmm0);
+        pmaddwd_r2r(xmm3, xmm2);
+        paddd_r2r(xmm0, xmm4);
+        paddd_r2r(xmm2, xmm4);
+        i -= 16;
+    }
+    movdqa_r2r(xmm4, xmm0);
+    psrldq_i2r(8, xmm0);
+    paddd_r2r(xmm0, xmm4);
+    movdqa_r2r(xmm4, xmm0);
+    psrldq_i2r(4, xmm0);
+    paddd_r2r(xmm0, xmm4);
+    movd_r2m(xmm4, y);
+#elif defined(__BLACKFIN_ASM__)
+    fir->history[fir->curr_pos] = sample;
+    fir->history[fir->curr_pos + fir->taps] = sample;
+    y = dot_asm((int16_t*)fir->coeffs, &fir->history[fir->curr_pos], fir->taps);
+#else
+    int i;
+    int offset1;
+    int offset2;
+
+    fir->history[fir->curr_pos] = sample;
+
+    offset2 = fir->curr_pos;
+    offset1 = fir->taps - offset2;
+    y = 0;
+    for (i = fir->taps - 1;  i >= offset1;  i--)
+        y += fir->coeffs[i]*fir->history[i - offset1];
+    for (  ;  i >= 0;  i--)
+        y += fir->coeffs[i]*fir->history[i + offset2];
+#endif
+    if (fir->curr_pos <= 0)
+    	fir->curr_pos = fir->taps;
+    fir->curr_pos--;
+    return (int16_t) (y >> 15);
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ const int16_t *fir32_create(fir32_state_t *fir,
+                                              const int32_t *coeffs,
+                                              int taps)
+{
+    fir->taps = taps;
+    fir->curr_pos = taps - 1;
+    fir->coeffs = coeffs;
+    fir->history = (int16_t *) malloc(taps*sizeof(int16_t));
+    if (fir->history)
+    	memset(fir->history, '\0', taps*sizeof(int16_t));
+    return fir->history;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ void fir32_flush(fir32_state_t *fir)
+{
+    memset(fir->history, 0, fir->taps*sizeof(int16_t));
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ void fir32_free(fir32_state_t *fir)
+{
+    free(fir->history);
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t fir32(fir32_state_t *fir, int16_t sample)
+{
+    int i;
+    int32_t y;
+    int offset1;
+    int offset2;
+
+    fir->history[fir->curr_pos] = sample;
+    offset2 = fir->curr_pos;
+    offset1 = fir->taps - offset2;
+    y = 0;
+    for (i = fir->taps - 1;  i >= offset1;  i--)
+        y += fir->coeffs[i]*fir->history[i - offset1];
+    for (  ;  i >= 0;  i--)
+        y += fir->coeffs[i]*fir->history[i + offset2];
+    if (fir->curr_pos <= 0)
+    	fir->curr_pos = fir->taps;
+    fir->curr_pos--;
+    return (int16_t) (y >> 15);
+}
+/*- End of function --------------------------------------------------------*/
+
+#ifndef __KERNEL__
+static __inline__ const float *fir_float_create(fir_float_state_t *fir,
+                                                const float *coeffs,
+    	    	    	                        int taps)
+{
+    fir->taps = taps;
+    fir->curr_pos = taps - 1;
+    fir->coeffs = coeffs;
+    fir->history = (float *) malloc(taps*sizeof(float));
+    if (fir->history)
+        memset(fir->history, '\0', taps*sizeof(float));
+    return fir->history;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ void fir_float_free(fir_float_state_t *fir)
+{
+    free(fir->history);
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t fir_float(fir_float_state_t *fir, int16_t sample)
+{
+    int i;
+    float y;
+    int offset1;
+    int offset2;
+
+    fir->history[fir->curr_pos] = sample;
+
+    offset2 = fir->curr_pos;
+    offset1 = fir->taps - offset2;
+    y = 0;
+    for (i = fir->taps - 1;  i >= offset1;  i--)
+        y += fir->coeffs[i]*fir->history[i - offset1];
+    for (  ;  i >= 0;  i--)
+        y += fir->coeffs[i]*fir->history[i + offset2];
+    if (fir->curr_pos <= 0)
+    	fir->curr_pos = fir->taps;
+    fir->curr_pos--;
+    return  (int16_t) y;
+}
+/*- End of function --------------------------------------------------------*/
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/

drivers/staging/echo/mmx.h

···
+/*
+ * mmx.h
+ * Copyright (C) 1997-2001 H. Dietz and R. Fisher
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef AVCODEC_I386MMX_H
+#define AVCODEC_I386MMX_H
+
+/*
+ * The type of an value that fits in an MMX register (note that long
+ * long constant values MUST be suffixed by LL and unsigned long long
+ * values by ULL, lest they be truncated by the compiler)
+ */
+
+typedef        union {
+        long long               q;      /* Quadword (64-bit) value */
+        unsigned long long      uq;     /* Unsigned Quadword */
+        int                     d[2];   /* 2 Doubleword (32-bit) values */
+        unsigned int            ud[2];  /* 2 Unsigned Doubleword */
+        short                   w[4];   /* 4 Word (16-bit) values */
+        unsigned short          uw[4];  /* 4 Unsigned Word */
+        char                    b[8];   /* 8 Byte (8-bit) values */
+        unsigned char           ub[8];  /* 8 Unsigned Byte */
+        float                   s[2];   /* Single-precision (32-bit) value */
+} mmx_t;        /* On an 8-byte (64-bit) boundary */
+
+/* SSE registers */
+typedef union {
+	char b[16];
+} xmm_t;
+
+
+#define         mmx_i2r(op,imm,reg) \
+        __asm__ __volatile__ (#op " %0, %%" #reg \
+                              : /* nothing */ \
+                              : "i" (imm) )
+
+#define         mmx_m2r(op,mem,reg) \
+        __asm__ __volatile__ (#op " %0, %%" #reg \
+                              : /* nothing */ \
+                              : "m" (mem))
+
+#define         mmx_r2m(op,reg,mem) \
+        __asm__ __volatile__ (#op " %%" #reg ", %0" \
+                              : "=m" (mem) \
+                              : /* nothing */ )
+
+#define         mmx_r2r(op,regs,regd) \
+        __asm__ __volatile__ (#op " %" #regs ", %" #regd)
+
+
+#define         emms() __asm__ __volatile__ ("emms")
+
+#define         movd_m2r(var,reg)           mmx_m2r (movd, var, reg)
+#define         movd_r2m(reg,var)           mmx_r2m (movd, reg, var)
+#define         movd_r2r(regs,regd)         mmx_r2r (movd, regs, regd)
+
+#define         movq_m2r(var,reg)           mmx_m2r (movq, var, reg)
+#define         movq_r2m(reg,var)           mmx_r2m (movq, reg, var)
+#define         movq_r2r(regs,regd)         mmx_r2r (movq, regs, regd)
+
+#define         packssdw_m2r(var,reg)       mmx_m2r (packssdw, var, reg)
+#define         packssdw_r2r(regs,regd)     mmx_r2r (packssdw, regs, regd)
+#define         packsswb_m2r(var,reg)       mmx_m2r (packsswb, var, reg)
+#define         packsswb_r2r(regs,regd)     mmx_r2r (packsswb, regs, regd)
+
+#define         packuswb_m2r(var,reg)       mmx_m2r (packuswb, var, reg)
+#define         packuswb_r2r(regs,regd)     mmx_r2r (packuswb, regs, regd)
+
+#define         paddb_m2r(var,reg)          mmx_m2r (paddb, var, reg)
+#define         paddb_r2r(regs,regd)        mmx_r2r (paddb, regs, regd)
+#define         paddd_m2r(var,reg)          mmx_m2r (paddd, var, reg)
+#define         paddd_r2r(regs,regd)        mmx_r2r (paddd, regs, regd)
+#define         paddw_m2r(var,reg)          mmx_m2r (paddw, var, reg)
+#define         paddw_r2r(regs,regd)        mmx_r2r (paddw, regs, regd)
+
+#define         paddsb_m2r(var,reg)         mmx_m2r (paddsb, var, reg)
+#define         paddsb_r2r(regs,regd)       mmx_r2r (paddsb, regs, regd)
+#define         paddsw_m2r(var,reg)         mmx_m2r (paddsw, var, reg)
+#define         paddsw_r2r(regs,regd)       mmx_r2r (paddsw, regs, regd)
+
+#define         paddusb_m2r(var,reg)        mmx_m2r (paddusb, var, reg)
+#define         paddusb_r2r(regs,regd)      mmx_r2r (paddusb, regs, regd)
+#define         paddusw_m2r(var,reg)        mmx_m2r (paddusw, var, reg)
+#define         paddusw_r2r(regs,regd)      mmx_r2r (paddusw, regs, regd)
+
+#define         pand_m2r(var,reg)           mmx_m2r (pand, var, reg)
+#define         pand_r2r(regs,regd)         mmx_r2r (pand, regs, regd)
+
+#define         pandn_m2r(var,reg)          mmx_m2r (pandn, var, reg)
+#define         pandn_r2r(regs,regd)        mmx_r2r (pandn, regs, regd)
+
+#define         pcmpeqb_m2r(var,reg)        mmx_m2r (pcmpeqb, var, reg)
+#define         pcmpeqb_r2r(regs,regd)      mmx_r2r (pcmpeqb, regs, regd)
+#define         pcmpeqd_m2r(var,reg)        mmx_m2r (pcmpeqd, var, reg)
+#define         pcmpeqd_r2r(regs,regd)      mmx_r2r (pcmpeqd, regs, regd)
+#define         pcmpeqw_m2r(var,reg)        mmx_m2r (pcmpeqw, var, reg)
+#define         pcmpeqw_r2r(regs,regd)      mmx_r2r (pcmpeqw, regs, regd)
+
+#define         pcmpgtb_m2r(var,reg)        mmx_m2r (pcmpgtb, var, reg)
+#define         pcmpgtb_r2r(regs,regd)      mmx_r2r (pcmpgtb, regs, regd)
+#define         pcmpgtd_m2r(var,reg)        mmx_m2r (pcmpgtd, var, reg)
+#define         pcmpgtd_r2r(regs,regd)      mmx_r2r (pcmpgtd, regs, regd)
+#define         pcmpgtw_m2r(var,reg)        mmx_m2r (pcmpgtw, var, reg)
+#define         pcmpgtw_r2r(regs,regd)      mmx_r2r (pcmpgtw, regs, regd)
+
+#define         pmaddwd_m2r(var,reg)        mmx_m2r (pmaddwd, var, reg)
+#define         pmaddwd_r2r(regs,regd)      mmx_r2r (pmaddwd, regs, regd)
+
+#define         pmulhw_m2r(var,reg)         mmx_m2r (pmulhw, var, reg)
+#define         pmulhw_r2r(regs,regd)       mmx_r2r (pmulhw, regs, regd)
+
+#define         pmullw_m2r(var,reg)         mmx_m2r (pmullw, var, reg)
+#define         pmullw_r2r(regs,regd)       mmx_r2r (pmullw, regs, regd)
+
+#define         por_m2r(var,reg)            mmx_m2r (por, var, reg)
+#define         por_r2r(regs,regd)          mmx_r2r (por, regs, regd)
+
+#define         pslld_i2r(imm,reg)          mmx_i2r (pslld, imm, reg)
+#define         pslld_m2r(var,reg)          mmx_m2r (pslld, var, reg)
+#define         pslld_r2r(regs,regd)        mmx_r2r (pslld, regs, regd)
+#define         psllq_i2r(imm,reg)          mmx_i2r (psllq, imm, reg)
+#define         psllq_m2r(var,reg)          mmx_m2r (psllq, var, reg)
+#define         psllq_r2r(regs,regd)        mmx_r2r (psllq, regs, regd)
+#define         psllw_i2r(imm,reg)          mmx_i2r (psllw, imm, reg)
+#define         psllw_m2r(var,reg)          mmx_m2r (psllw, var, reg)
+#define         psllw_r2r(regs,regd)        mmx_r2r (psllw, regs, regd)
+
+#define         psrad_i2r(imm,reg)          mmx_i2r (psrad, imm, reg)
+#define         psrad_m2r(var,reg)          mmx_m2r (psrad, var, reg)
+#define         psrad_r2r(regs,regd)        mmx_r2r (psrad, regs, regd)
+#define         psraw_i2r(imm,reg)          mmx_i2r (psraw, imm, reg)
+#define         psraw_m2r(var,reg)          mmx_m2r (psraw, var, reg)
+#define         psraw_r2r(regs,regd)        mmx_r2r (psraw, regs, regd)
+
+#define         psrld_i2r(imm,reg)          mmx_i2r (psrld, imm, reg)
+#define         psrld_m2r(var,reg)          mmx_m2r (psrld, var, reg)
+#define         psrld_r2r(regs,regd)        mmx_r2r (psrld, regs, regd)
+#define         psrlq_i2r(imm,reg)          mmx_i2r (psrlq, imm, reg)
+#define         psrlq_m2r(var,reg)          mmx_m2r (psrlq, var, reg)
+#define         psrlq_r2r(regs,regd)        mmx_r2r (psrlq, regs, regd)
+#define         psrlw_i2r(imm,reg)          mmx_i2r (psrlw, imm, reg)
+#define         psrlw_m2r(var,reg)          mmx_m2r (psrlw, var, reg)
+#define         psrlw_r2r(regs,regd)        mmx_r2r (psrlw, regs, regd)
+
+#define         psubb_m2r(var,reg)          mmx_m2r (psubb, var, reg)
+#define         psubb_r2r(regs,regd)        mmx_r2r (psubb, regs, regd)
+#define         psubd_m2r(var,reg)          mmx_m2r (psubd, var, reg)
+#define         psubd_r2r(regs,regd)        mmx_r2r (psubd, regs, regd)
+#define         psubw_m2r(var,reg)          mmx_m2r (psubw, var, reg)
+#define         psubw_r2r(regs,regd)        mmx_r2r (psubw, regs, regd)
+
+#define         psubsb_m2r(var,reg)         mmx_m2r (psubsb, var, reg)
+#define         psubsb_r2r(regs,regd)       mmx_r2r (psubsb, regs, regd)
+#define         psubsw_m2r(var,reg)         mmx_m2r (psubsw, var, reg)
+#define         psubsw_r2r(regs,regd)       mmx_r2r (psubsw, regs, regd)
+
+#define         psubusb_m2r(var,reg)        mmx_m2r (psubusb, var, reg)
+#define         psubusb_r2r(regs,regd)      mmx_r2r (psubusb, regs, regd)
+#define         psubusw_m2r(var,reg)        mmx_m2r (psubusw, var, reg)
+#define         psubusw_r2r(regs,regd)      mmx_r2r (psubusw, regs, regd)
+
+#define         punpckhbw_m2r(var,reg)      mmx_m2r (punpckhbw, var, reg)
+#define         punpckhbw_r2r(regs,regd)    mmx_r2r (punpckhbw, regs, regd)
+#define         punpckhdq_m2r(var,reg)      mmx_m2r (punpckhdq, var, reg)
+#define         punpckhdq_r2r(regs,regd)    mmx_r2r (punpckhdq, regs, regd)
+#define         punpckhwd_m2r(var,reg)      mmx_m2r (punpckhwd, var, reg)
+#define         punpckhwd_r2r(regs,regd)    mmx_r2r (punpckhwd, regs, regd)
+
+#define         punpcklbw_m2r(var,reg)      mmx_m2r (punpcklbw, var, reg)
+#define         punpcklbw_r2r(regs,regd)    mmx_r2r (punpcklbw, regs, regd)
+#define         punpckldq_m2r(var,reg)      mmx_m2r (punpckldq, var, reg)
+#define         punpckldq_r2r(regs,regd)    mmx_r2r (punpckldq, regs, regd)
+#define         punpcklwd_m2r(var,reg)      mmx_m2r (punpcklwd, var, reg)
+#define         punpcklwd_r2r(regs,regd)    mmx_r2r (punpcklwd, regs, regd)
+
+#define         pxor_m2r(var,reg)           mmx_m2r (pxor, var, reg)
+#define         pxor_r2r(regs,regd)         mmx_r2r (pxor, regs, regd)
+
+
+/* 3DNOW extensions */
+
+#define         pavgusb_m2r(var,reg)        mmx_m2r (pavgusb, var, reg)
+#define         pavgusb_r2r(regs,regd)      mmx_r2r (pavgusb, regs, regd)
+
+
+/* AMD MMX extensions - also available in intel SSE */
+
+
+#define         mmx_m2ri(op,mem,reg,imm) \
+        __asm__ __volatile__ (#op " %1, %0, %%" #reg \
+                              : /* nothing */ \
+                              : "m" (mem), "i" (imm))
+#define         mmx_r2ri(op,regs,regd,imm) \
+        __asm__ __volatile__ (#op " %0, %%" #regs ", %%" #regd \
+                              : /* nothing */ \
+                              : "i" (imm) )
+
+#define         mmx_fetch(mem,hint) \
+        __asm__ __volatile__ ("prefetch" #hint " %0" \
+                              : /* nothing */ \
+                              : "m" (mem))
+
+
+#define         maskmovq(regs,maskreg)      mmx_r2ri (maskmovq, regs, maskreg)
+
+#define         movntq_r2m(mmreg,var)       mmx_r2m (movntq, mmreg, var)
+
+#define         pavgb_m2r(var,reg)          mmx_m2r (pavgb, var, reg)
+#define         pavgb_r2r(regs,regd)        mmx_r2r (pavgb, regs, regd)
+#define         pavgw_m2r(var,reg)          mmx_m2r (pavgw, var, reg)
+#define         pavgw_r2r(regs,regd)        mmx_r2r (pavgw, regs, regd)
+
+#define         pextrw_r2r(mmreg,reg,imm)   mmx_r2ri (pextrw, mmreg, reg, imm)
+
+#define         pinsrw_r2r(reg,mmreg,imm)   mmx_r2ri (pinsrw, reg, mmreg, imm)
+
+#define         pmaxsw_m2r(var,reg)         mmx_m2r (pmaxsw, var, reg)
+#define         pmaxsw_r2r(regs,regd)       mmx_r2r (pmaxsw, regs, regd)
+
+#define         pmaxub_m2r(var,reg)         mmx_m2r (pmaxub, var, reg)
+#define         pmaxub_r2r(regs,regd)       mmx_r2r (pmaxub, regs, regd)
+
+#define         pminsw_m2r(var,reg)         mmx_m2r (pminsw, var, reg)
+#define         pminsw_r2r(regs,regd)       mmx_r2r (pminsw, regs, regd)
+
+#define         pminub_m2r(var,reg)         mmx_m2r (pminub, var, reg)
+#define         pminub_r2r(regs,regd)       mmx_r2r (pminub, regs, regd)
+
+#define         pmovmskb(mmreg,reg) \
+        __asm__ __volatile__ ("movmskps %" #mmreg ", %" #reg)
+
+#define         pmulhuw_m2r(var,reg)        mmx_m2r (pmulhuw, var, reg)
+#define         pmulhuw_r2r(regs,regd)      mmx_r2r (pmulhuw, regs, regd)
+
+#define         prefetcht0(mem)             mmx_fetch (mem, t0)
+#define         prefetcht1(mem)             mmx_fetch (mem, t1)
+#define         prefetcht2(mem)             mmx_fetch (mem, t2)
+#define         prefetchnta(mem)            mmx_fetch (mem, nta)
+
+#define         psadbw_m2r(var,reg)         mmx_m2r (psadbw, var, reg)
+#define         psadbw_r2r(regs,regd)       mmx_r2r (psadbw, regs, regd)
+
+#define         pshufw_m2r(var,reg,imm)     mmx_m2ri(pshufw, var, reg, imm)
+#define         pshufw_r2r(regs,regd,imm)   mmx_r2ri(pshufw, regs, regd, imm)
+
+#define         sfence() __asm__ __volatile__ ("sfence\n\t")
+
+/* SSE2 */
+#define         pshufhw_m2r(var,reg,imm)    mmx_m2ri(pshufhw, var, reg, imm)
+#define         pshufhw_r2r(regs,regd,imm)  mmx_r2ri(pshufhw, regs, regd, imm)
+#define         pshuflw_m2r(var,reg,imm)    mmx_m2ri(pshuflw, var, reg, imm)
+#define         pshuflw_r2r(regs,regd,imm)  mmx_r2ri(pshuflw, regs, regd, imm)
+
+#define         pshufd_r2r(regs,regd,imm)   mmx_r2ri(pshufd, regs, regd, imm)
+
+#define         movdqa_m2r(var,reg)         mmx_m2r (movdqa, var, reg)
+#define         movdqa_r2m(reg,var)         mmx_r2m (movdqa, reg, var)
+#define         movdqa_r2r(regs,regd)       mmx_r2r (movdqa, regs, regd)
+#define         movdqu_m2r(var,reg)         mmx_m2r (movdqu, var, reg)
+#define         movdqu_r2m(reg,var)         mmx_r2m (movdqu, reg, var)
+#define         movdqu_r2r(regs,regd)       mmx_r2r (movdqu, regs, regd)
+
+#define         pmullw_r2m(reg,var)         mmx_r2m (pmullw, reg, var)
+
+#define         pslldq_i2r(imm,reg)         mmx_i2r (pslldq, imm, reg)
+#define         psrldq_i2r(imm,reg)         mmx_i2r (psrldq, imm, reg)
+
+#define         punpcklqdq_r2r(regs,regd)   mmx_r2r (punpcklqdq, regs, regd)
+#define         punpckhqdq_r2r(regs,regd)   mmx_r2r (punpckhqdq, regs, regd)
+
+
+#endif /* AVCODEC_I386MMX_H */