Transceiver52M: Replace convolve and related calls with SSE implementation

This large patch replaced the convolve() call with an SSE vector
enabled version. The lower C and SSE intrinsic based code operates
on fixed and aligned vectors for the filter taps. The storage format
of interleaved I/Q for both complex and real vectors is maintained.

SSE filter tap values must:

  1. Start 16-byte aligned
  2. Number with a multiple of 4 between 4 and 20 for real taps
  3. Number with a multiple of 4 for complex taps

Non-compliant values will fall back to non-SSE usage. Fixed length
iterators mean that head and tail cases may require reallocation of
the input vector, which is automatically handled by the upper C++
interface.

Other calls are affected by these changes and adjusted or rewritten
accordingly. The underlying algorithms, however, are unchanged.

  generateGSMPulse()
  analyzeTrafficBurst()
  detectRACHBurst()

Intel SSE configuration is automatically detected and configured at
build time with Autoconf macros.

Signed-off-by: Thomas Tsou <tom@tsou.cc>

12 files changed, 1567 insertions, 408 deletions

diff --git a/Makefile.am b/Makefile.am
index 058876d..06251f0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -20,6 +20,7 @@
 
 include $(top_srcdir)/Makefile.common
 
+ACLOCAL_AMFLAGS = -I config
 AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES) $(USB_INCLUDES) $(WITH_INCLUDES)
 AM_CXXFLAGS = -Wall -pthread -ldl
 #AM_CXXFLAGS = -Wall -O2 -NDEBUG -pthread -ldl
diff --git a/Transceiver52M/Makefile.am b/Transceiver52M/Makefile.am
index 6fcef7c..67ab0ea 100644
--- a/Transceiver52M/Makefile.am
+++ b/Transceiver52M/Makefile.am
@@ -21,19 +21,18 @@
 
 include $(top_srcdir)/Makefile.common
 
+AM_CFLAGS = $(STD_DEFINES_AND_INCLUDES) -std=gnu99 -march=native
+AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES)
+AM_CXXFLAGS = -ldl -lpthread
+
 #UHD wins if both are defined
 if UHD
-AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES) $(UHD_CFLAGS)
+AM_CPPFLAGS += $(UHD_CFLAGS)
 else
 if USRP1
-AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES) $(USRP_CFLAGS)
-else
-#we should never be here, as this doesn't build if one of the above
-#doesn't exist
-AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES)
+AM_CPPFLAGS += $(USRP_CFLAGS)
 endif
 endif
-AM_CXXFLAGS = -ldl -lpthread
 
 rev2dir = $(datadir)/usrp/rev2
 rev4dir = $(datadir)/usrp/rev4
@@ -53,7 +52,8 @@ COMMON_SOURCES = \
 	radioClock.cpp \
 	sigProcLib.cpp \
 	Transceiver.cpp \
-	DummyLoad.cpp
+	DummyLoad.cpp \
+	convolve.c
 
 libtransceiver_la_SOURCES = \
 	$(COMMON_SOURCES) \
@@ -75,7 +75,8 @@ noinst_HEADERS = \
 	USRPDevice.h \
 	DummyLoad.h \
 	rcvLPF_651.h \
-	sendLPF_961.h
+	sendLPF_961.h \
+	convolve.h
 
 USRPping_SOURCES = USRPping.cpp
 USRPping_LDADD = \
diff --git a/Transceiver52M/convolve.c b/Transceiver52M/convolve.c
new file mode 100644
index 0000000..6f48ea0
--- /dev/null
+++ b/Transceiver52M/convolve.c
@@ -0,0 +1,714 @@
+/*
+ * SSE Convolution
+ * Copyright (C) 2012, 2013 Thomas Tsou <tom@tsou.cc>
+ *
+ * This 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 2.1 of the License, or (at your option) any later version.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <malloc.h>
+#include <string.h>
+#include <stdio.h>
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_SSE3
+#include <xmmintrin.h>
+#include <pmmintrin.h>
+
+/* 4-tap SSE complex-real convolution */
+static void sse_conv_real4(float *restrict x,
+			   float *restrict h,
+			   float *restrict y,
+			   int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7;
+
+	/* Load (aligned) filter taps */
+	m0 = _mm_load_ps(&h[0]);
+	m1 = _mm_load_ps(&h[4]);
+	m7 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+
+	for (int i = 0; i < len; i++) {
+		/* Load (unaligned) input data */
+		m0 = _mm_loadu_ps(&x[2 * i + 0]);
+		m1 = _mm_loadu_ps(&x[2 * i + 4]);
+		m2 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m3 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+
+		/* Quad multiply */
+		m4 = _mm_mul_ps(m2, m7);
+		m5 = _mm_mul_ps(m3, m7);
+
+		/* Sum and store */
+		m6 = _mm_hadd_ps(m4, m5);
+		m0 = _mm_hadd_ps(m6, m6);
+
+		_mm_store_ss(&y[2 * i + 0], m0);
+		m0 = _mm_shuffle_ps(m0, m0, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m0);
+	}
+}
+
+/* 8-tap SSE complex-real convolution */
+static void sse_conv_real8(float *restrict x,
+			   float *restrict h,
+			   float *restrict y,
+			   int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7, m8, m9;
+
+	/* Load (aligned) filter taps */
+	m0 = _mm_load_ps(&h[0]);
+	m1 = _mm_load_ps(&h[4]);
+	m2 = _mm_load_ps(&h[8]);
+	m3 = _mm_load_ps(&h[12]);
+
+	m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+	m5 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+
+	for (int i = 0; i < len; i++) {
+		/* Load (unaligned) input data */
+		m0 = _mm_loadu_ps(&x[2 * i + 0]);
+		m1 = _mm_loadu_ps(&x[2 * i + 4]);
+		m2 = _mm_loadu_ps(&x[2 * i + 8]);
+		m3 = _mm_loadu_ps(&x[2 * i + 12]);
+
+		m6 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m7 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+		m8 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+		m9 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+		/* Quad multiply */
+		m6 = _mm_mul_ps(m6, m4);
+		m7 = _mm_mul_ps(m7, m4);
+		m8 = _mm_mul_ps(m8, m5);
+		m9 = _mm_mul_ps(m9, m5);
+
+		/* Sum and store */
+		m6 = _mm_add_ps(m6, m8);
+		m7 = _mm_add_ps(m7, m9);
+		m6 = _mm_hadd_ps(m6, m7);
+		m6 = _mm_hadd_ps(m6, m6);
+
+		_mm_store_ss(&y[2 * i + 0], m6);
+		m6 = _mm_shuffle_ps(m6, m6, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m6);
+	}
+}
+
+/* 12-tap SSE complex-real convolution */
+static void sse_conv_real12(float *restrict x,
+			    float *restrict h,
+			    float *restrict y,
+			    int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7;
+	__m128 m8, m9, m10, m11, m12, m13, m14;
+
+	/* Load (aligned) filter taps */
+	m0 = _mm_load_ps(&h[0]);
+	m1 = _mm_load_ps(&h[4]);
+	m2 = _mm_load_ps(&h[8]);
+	m3 = _mm_load_ps(&h[12]);
+	m4 = _mm_load_ps(&h[16]);
+	m5 = _mm_load_ps(&h[20]);
+
+	m12 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+	m13 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+	m14 = _mm_shuffle_ps(m4, m5, _MM_SHUFFLE(0, 2, 0, 2));
+
+	for (int i = 0; i < len; i++) {
+		/* Load (unaligned) input data */
+		m0 = _mm_loadu_ps(&x[2 * i + 0]);
+		m1 = _mm_loadu_ps(&x[2 * i + 4]);
+		m2 = _mm_loadu_ps(&x[2 * i + 8]);
+		m3 = _mm_loadu_ps(&x[2 * i + 12]);
+
+		m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m5 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+		m6 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+		m7 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+		m0 = _mm_loadu_ps(&x[2 * i + 16]);
+		m1 = _mm_loadu_ps(&x[2 * i + 20]);
+
+		m8 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m9 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+
+		/* Quad multiply */
+		m0 = _mm_mul_ps(m4, m12);
+		m1 = _mm_mul_ps(m5, m12);
+		m2 = _mm_mul_ps(m6, m13);
+		m3 = _mm_mul_ps(m7, m13);
+		m4 = _mm_mul_ps(m8, m14);
+		m5 = _mm_mul_ps(m9, m14);
+
+		/* Sum and store */
+		m8  = _mm_add_ps(m0, m2);
+		m9  = _mm_add_ps(m1, m3);
+		m10 = _mm_add_ps(m8, m4);
+		m11 = _mm_add_ps(m9, m5);
+
+		m2 = _mm_hadd_ps(m10, m11);
+		m3 = _mm_hadd_ps(m2, m2);
+
+		_mm_store_ss(&y[2 * i + 0], m3);
+		m3 = _mm_shuffle_ps(m3, m3, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m3);
+	}
+}
+
+/* 16-tap SSE complex-real convolution */
+static void sse_conv_real16(float *restrict x,
+			    float *restrict h,
+			    float *restrict y,
+			    int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7;
+	__m128 m8, m9, m10, m11, m12, m13, m14, m15;
+
+	/* Load (aligned) filter taps */
+	m0 = _mm_load_ps(&h[0]);
+	m1 = _mm_load_ps(&h[4]);
+	m2 = _mm_load_ps(&h[8]);
+	m3 = _mm_load_ps(&h[12]);
+
+	m4 = _mm_load_ps(&h[16]);
+	m5 = _mm_load_ps(&h[20]);
+	m6 = _mm_load_ps(&h[24]);
+	m7 = _mm_load_ps(&h[28]);
+
+	m12 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+	m13 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+	m14 = _mm_shuffle_ps(m4, m5, _MM_SHUFFLE(0, 2, 0, 2));
+	m15 = _mm_shuffle_ps(m6, m7, _MM_SHUFFLE(0, 2, 0, 2));
+
+	for (int i = 0; i < len; i++) {
+		/* Load (unaligned) input data */
+		m0 = _mm_loadu_ps(&x[2 * i + 0]);
+		m1 = _mm_loadu_ps(&x[2 * i + 4]);
+		m2 = _mm_loadu_ps(&x[2 * i + 8]);
+		m3 = _mm_loadu_ps(&x[2 * i + 12]);
+
+		m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m5 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+		m6 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+		m7 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+		m0 = _mm_loadu_ps(&x[2 * i + 16]);
+		m1 = _mm_loadu_ps(&x[2 * i + 20]);
+		m2 = _mm_loadu_ps(&x[2 * i + 24]);
+		m3 = _mm_loadu_ps(&x[2 * i + 28]);
+
+		m8  = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m9  = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+		m10 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+		m11 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+		/* Quad multiply */
+		m0 = _mm_mul_ps(m4, m12);
+		m1 = _mm_mul_ps(m5, m12);
+		m2 = _mm_mul_ps(m6, m13);
+		m3 = _mm_mul_ps(m7, m13);
+
+		m4 = _mm_mul_ps(m8, m14);
+		m5 = _mm_mul_ps(m9, m14);
+		m6 = _mm_mul_ps(m10, m15);
+		m7 = _mm_mul_ps(m11, m15);
+
+		/* Sum and store */
+		m8  = _mm_add_ps(m0, m2);
+		m9  = _mm_add_ps(m1, m3);
+		m10 = _mm_add_ps(m4, m6);
+		m11 = _mm_add_ps(m5, m7);
+
+		m0 = _mm_add_ps(m8, m10);
+		m1 = _mm_add_ps(m9, m11);
+		m2 = _mm_hadd_ps(m0, m1);
+		m3 = _mm_hadd_ps(m2, m2);
+
+		_mm_store_ss(&y[2 * i + 0], m3);
+		m3 = _mm_shuffle_ps(m3, m3, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m3);
+	}
+}
+
+/* 20-tap SSE complex-real convolution */
+static void sse_conv_real20(float *restrict x,
+			    float *restrict h,
+			    float *restrict y,
+			    int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7;
+	__m128 m8, m9, m11, m12, m13, m14, m15;
+
+	/* Load (aligned) filter taps */
+	m0 = _mm_load_ps(&h[0]);
+	m1 = _mm_load_ps(&h[4]);
+	m2 = _mm_load_ps(&h[8]);
+	m3 = _mm_load_ps(&h[12]);
+	m4 = _mm_load_ps(&h[16]);
+	m5 = _mm_load_ps(&h[20]);
+	m6 = _mm_load_ps(&h[24]);
+	m7 = _mm_load_ps(&h[28]);
+	m8 = _mm_load_ps(&h[32]);
+	m9 = _mm_load_ps(&h[36]);
+
+	m11 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+	m12 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+	m13 = _mm_shuffle_ps(m4, m5, _MM_SHUFFLE(0, 2, 0, 2));
+	m14 = _mm_shuffle_ps(m6, m7, _MM_SHUFFLE(0, 2, 0, 2));
+	m15 = _mm_shuffle_ps(m8, m9, _MM_SHUFFLE(0, 2, 0, 2));
+
+	for (int i = 0; i < len; i++) {
+		/* Multiply-accumulate first 12 taps */
+		m0 = _mm_loadu_ps(&x[2 * i + 0]);
+		m1 = _mm_loadu_ps(&x[2 * i + 4]);
+		m2 = _mm_loadu_ps(&x[2 * i + 8]);
+		m3 = _mm_loadu_ps(&x[2 * i + 12]);
+		m4 = _mm_loadu_ps(&x[2 * i + 16]);
+		m5 = _mm_loadu_ps(&x[2 * i + 20]);
+
+		m6  = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m7  = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+		m8  = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+		m9  = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+		m0  = _mm_shuffle_ps(m4, m5, _MM_SHUFFLE(0, 2, 0, 2));
+		m1  = _mm_shuffle_ps(m4, m5, _MM_SHUFFLE(1, 3, 1, 3));
+
+		m2 = _mm_mul_ps(m6, m11);
+		m3 = _mm_mul_ps(m7, m11);
+		m4 = _mm_mul_ps(m8, m12);
+		m5 = _mm_mul_ps(m9, m12);
+		m6 = _mm_mul_ps(m0, m13);
+		m7 = _mm_mul_ps(m1, m13);
+
+		m0  = _mm_add_ps(m2, m4);
+		m1  = _mm_add_ps(m3, m5);
+		m8  = _mm_add_ps(m0, m6);
+		m9  = _mm_add_ps(m1, m7);
+
+		/* Multiply-accumulate last 8 taps */
+		m0 = _mm_loadu_ps(&x[2 * i + 24]);
+		m1 = _mm_loadu_ps(&x[2 * i + 28]);
+		m2 = _mm_loadu_ps(&x[2 * i + 32]);
+		m3 = _mm_loadu_ps(&x[2 * i + 36]);
+
+		m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+		m5 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+		m6 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+		m7 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+		m0 = _mm_mul_ps(m4, m14);
+		m1 = _mm_mul_ps(m5, m14);
+		m2 = _mm_mul_ps(m6, m15);
+		m3 = _mm_mul_ps(m7, m15);
+
+		m4  = _mm_add_ps(m0, m2);
+		m5  = _mm_add_ps(m1, m3);
+
+		/* Final sum and store */
+		m0 = _mm_add_ps(m8, m4);
+		m1 = _mm_add_ps(m9, m5);
+		m2 = _mm_hadd_ps(m0, m1);
+		m3 = _mm_hadd_ps(m2, m2);
+
+		_mm_store_ss(&y[2 * i + 0], m3);
+		m3 = _mm_shuffle_ps(m3, m3, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m3);
+	}
+}
+
+/* 4*N-tap SSE complex-real convolution */
+static void sse_conv_real4n(float *x, float *h, float *y, int h_len, int len)
+{
+	__m128 m0, m1, m2, m4, m5, m6, m7;
+
+	for (int i = 0; i < len; i++) {
+		/* Zero */
+		m6 = _mm_setzero_ps();
+		m7 = _mm_setzero_ps();
+
+		for (int n = 0; n < h_len / 4; n++) {
+			/* Load (aligned) filter taps */
+			m0 = _mm_load_ps(&h[8 * n + 0]);
+			m1 = _mm_load_ps(&h[8 * n + 4]);
+			m2 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+
+			/* Load (unaligned) input data */
+			m0 = _mm_loadu_ps(&x[2 * i + 8 * n + 0]);
+			m1 = _mm_loadu_ps(&x[2 * i + 8 * n + 4]);
+			m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+			m5 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+
+			/* Quad multiply */
+			m0 = _mm_mul_ps(m2, m4);
+			m1 = _mm_mul_ps(m2, m5);
+
+			/* Accumulate */
+			m6 = _mm_add_ps(m6, m0);
+			m7 = _mm_add_ps(m7, m1);
+		}
+
+		m0 = _mm_hadd_ps(m6, m7);
+		m0 = _mm_hadd_ps(m0, m0);
+
+		_mm_store_ss(&y[2 * i + 0], m0);
+		m0 = _mm_shuffle_ps(m0, m0, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m0);
+	}
+}
+
+/* 4*N-tap SSE complex-complex convolution */
+static void sse_conv_cmplx_4n(float *x, float *h, float *y, int h_len, int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7;
+
+	for (int i = 0; i < len; i++) {
+		/* Zero */
+		m6 = _mm_setzero_ps();
+		m7 = _mm_setzero_ps();
+
+		for (int n = 0; n < h_len / 4; n++) {
+			/* Load (aligned) filter taps */
+			m0 = _mm_load_ps(&h[8 * n + 0]);
+			m1 = _mm_load_ps(&h[8 * n + 4]);
+			m2 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+			m3 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+
+			/* Load (unaligned) input data */
+			m0 = _mm_loadu_ps(&x[2 * i + 8 * n + 0]);
+			m1 = _mm_loadu_ps(&x[2 * i + 8 * n + 4]);
+			m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+			m5 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+
+			/* Quad multiply */
+			m0 = _mm_mul_ps(m2, m4);
+			m1 = _mm_mul_ps(m3, m5);
+
+			m2 = _mm_mul_ps(m2, m5);
+			m3 = _mm_mul_ps(m3, m4);
+
+			/* Sum */
+			m0 = _mm_sub_ps(m0, m1);
+			m2 = _mm_add_ps(m2, m3);
+
+			/* Accumulate */
+			m6 = _mm_add_ps(m6, m0);
+			m7 = _mm_add_ps(m7, m2);
+		}
+
+		m0 = _mm_hadd_ps(m6, m7);
+		m0 = _mm_hadd_ps(m0, m0);
+
+		_mm_store_ss(&y[2 * i + 0], m0);
+		m0 = _mm_shuffle_ps(m0, m0, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m0);
+	}
+}
+
+/* 8*N-tap SSE complex-complex convolution */
+static void sse_conv_cmplx_8n(float *x, float *h, float *y, int h_len, int len)
+{
+	__m128 m0, m1, m2, m3, m4, m5, m6, m7;
+	__m128 m8, m9, m10, m11, m12, m13, m14, m15;
+
+	for (int i = 0; i < len; i++) {
+		/* Zero */
+		m12 = _mm_setzero_ps();
+		m13 = _mm_setzero_ps();
+		m14 = _mm_setzero_ps();
+		m15 = _mm_setzero_ps();
+
+		for (int n = 0; n < h_len / 8; n++) {
+			/* Load (aligned) filter taps */
+			m0 = _mm_load_ps(&h[16 * n + 0]);
+			m1 = _mm_load_ps(&h[16 * n + 4]);
+			m2 = _mm_load_ps(&h[16 * n + 8]);
+			m3 = _mm_load_ps(&h[16 * n + 12]);
+
+			m4 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+			m5 = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+			m6 = _mm_shuffle_ps(m2, m2, _MM_SHUFFLE(0, 2, 0, 2));
+			m7 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+			/* Load (unaligned) input data */
+			m0 = _mm_loadu_ps(&x[2 * i + 16 * n + 0]);
+			m1 = _mm_loadu_ps(&x[2 * i + 16 * n + 4]);
+			m2 = _mm_loadu_ps(&x[2 * i + 16 * n + 8]);
+			m3 = _mm_loadu_ps(&x[2 * i + 16 * n + 12]);
+
+			m8  = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(0, 2, 0, 2));
+			m9  = _mm_shuffle_ps(m0, m1, _MM_SHUFFLE(1, 3, 1, 3));
+			m10 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(0, 2, 0, 2));
+			m11 = _mm_shuffle_ps(m2, m3, _MM_SHUFFLE(1, 3, 1, 3));
+
+			/* Quad multiply */
+			m0 = _mm_mul_ps(m4, m8);
+			m1 = _mm_mul_ps(m5, m9);
+			m2 = _mm_mul_ps(m6, m10);
+			m3 = _mm_mul_ps(m7, m11);
+
+			m4 = _mm_mul_ps(m4, m9);
+			m5 = _mm_mul_ps(m5, m8);
+			m6 = _mm_mul_ps(m6, m11);
+			m7 = _mm_mul_ps(m7, m10);
+
+			/* Sum */
+			m0 = _mm_sub_ps(m0, m1);
+			m2 = _mm_sub_ps(m2, m3);
+			m4 = _mm_add_ps(m4, m5);
+			m6 = _mm_add_ps(m6, m7);
+
+			/* Accumulate */
+			m12 = _mm_add_ps(m12, m0);
+			m13 = _mm_add_ps(m13, m2);
+			m14 = _mm_add_ps(m14, m4);
+			m15 = _mm_add_ps(m15, m6);
+		}
+
+		m0 = _mm_add_ps(m12, m13);
+		m1 = _mm_add_ps(m14, m15);
+		m2 = _mm_hadd_ps(m0, m1);
+		m2 = _mm_hadd_ps(m2, m2);
+
+		_mm_store_ss(&y[2 * i + 0], m2);
+		m2 = _mm_shuffle_ps(m2, m2, _MM_SHUFFLE(0, 3, 2, 1));
+		_mm_store_ss(&y[2 * i + 1], m2);
+	}
+}
+#endif
+
+/* Base multiply and accumulate complex-real */
+static void mac_real(float *x, float *h, float *y)
+{
+	y[0] += x[0] * h[0];
+	y[1] += x[1] * h[0];
+}
+
+/* Base multiply and accumulate complex-complex */
+static void mac_cmplx(float *x, float *h, float *y)
+{
+	y[0] += x[0] * h[0] - x[1] * h[1];
+	y[1] += x[0] * h[1] + x[1] * h[0];
+}
+
+/* Base vector complex-complex multiply and accumulate */
+static void mac_real_vec_n(float *x, float *h, float *y,
+			   int len, int step, int offset)
+{
+	for (int i = offset; i < len; i += step)
+		mac_real(&x[2 * i], &h[2 * i], y);
+}
+
+/* Base vector complex-complex multiply and accumulate */
+static void mac_cmplx_vec_n(float *x, float *h, float *y,
+			    int len, int step, int offset)
+{
+	for (int i = offset; i < len; i += step)
+		mac_cmplx(&x[2 * i], &h[2 * i], y);
+}
+
+/* Base complex-real convolution */
+static int _base_convolve_real(float *x, int x_len,
+			       float *h, int h_len,
+			       float *y, int y_len,
+			       int start, int len,
+			       int step, int offset)
+{
+	for (int i = 0; i < len; i++) {
+		mac_real_vec_n(&x[2 * (i - (h_len - 1) + start)],
+			       h,
+			       &y[2 * i], h_len,
+			       step, offset);
+	}
+
+	return len;
+}
+
+/* Base complex-complex convolution */
+static int _base_convolve_complex(float *x, int x_len,
+				  float *h, int h_len,
+				  float *y, int y_len,
+				  int start, int len,
+				  int step, int offset)
+{
+	for (int i = 0; i < len; i++) {
+		mac_cmplx_vec_n(&x[2 * (i - (h_len - 1) + start)],
+				h,
+				&y[2 * i],
+				h_len, step, offset);
+	}
+
+	return len;
+}
+
+/* Buffer validity checks */
+static int bounds_check(int x_len, int h_len, int y_len,
+			int start, int len, int step)
+{
+	if ((x_len < 1) || (h_len < 1) ||
+	    (y_len < 1) || (len < 1) || (step < 1)) {
+		fprintf(stderr, "Convolve: Invalid input\n");
+		return -1;
+	}
+
+	if ((start + len > x_len) || (len > y_len) || (x_len < h_len)) {
+		fprintf(stderr, "Convolve: Boundary exception\n");
+		fprintf(stderr, "start: %i, len: %i, x: %i, h: %i, y: %i\n",
+				start, len, x_len, h_len, y_len);
+		return -1;
+	}
+
+	return 0;
+}
+
+/* API: Aligned complex-real */
+int convolve_real(float *x, int x_len,
+		  float *h, int h_len,
+		  float *y, int y_len,
+		  int start, int len,
+		  int step, int offset)
+{
+	void (*conv_func)(float *, float *, float *, int) = NULL;
+	void (*conv_func_n)(float *, float *, float *, int, int) = NULL;
+
+	if (bounds_check(x_len, h_len, y_len, start, len, step) < 0)
+		return -1;
+
+	memset(y, 0, len * 2 * sizeof(float));
+
+#ifdef HAVE_SSE3
+	if (step <= 4) {
+		switch (h_len) {
+		case 4:
+			conv_func = sse_conv_real4;
+			break;
+		case 8:
+			conv_func = sse_conv_real8;
+			break;
+		case 12:
+			conv_func = sse_conv_real12;
+			break;
+		case 16:
+			conv_func = sse_conv_real16;
+			break;
+		case 20:
+			conv_func = sse_conv_real20;
+			break;
+		default:
+			if (!(h_len % 4))
+				conv_func_n = sse_conv_real4n;
+		}
+	}
+#endif
+	if (conv_func) {
+		conv_func(&x[2 * (-(h_len - 1) + start)],
+			  h, y, len);
+	} else if (conv_func_n) {
+		conv_func_n(&x[2 * (-(h_len - 1) + start)],
+			    h, y, h_len, len);
+	} else {
+		_base_convolve_real(x, x_len,
+				    h, h_len,
+				    y, y_len,
+				    start, len, step, offset);
+	}
+
+	return len;
+}
+
+/* API: Aligned complex-complex */
+int convolve_complex(float *x, int x_len,
+		     float *h, int h_len,
+		     float *y, int y_len,
+		     int start, int len,
+		     int step, int offset)
+{
+	void (*conv_func)(float *, float *, float *, int, int) = NULL;
+
+	if (bounds_check(x_len, h_len, y_len, start, len, step) < 0)
+		return -1;
+
+	memset(y, 0, len * 2 * sizeof(float));
+
+#ifdef HAVE_SSE3
+	if (step <= 4) {
+		if (!(h_len % 8))
+			conv_func = sse_conv_cmplx_8n;
+		else if (!(h_len % 4))
+			conv_func = sse_conv_cmplx_4n;
+	}
+#endif
+	if (conv_func) {
+		conv_func(&x[2 * (-(h_len - 1) + start)],
+			  h, y, h_len, len);
+	} else {
+		_base_convolve_complex(x, x_len,
+				       h, h_len,
+				       y, y_len,
+				       start, len, step, offset);
+	}
+
+	return len;
+}
+
+/* API: Non-aligned (no SSE) complex-real */
+int base_convolve_real(float *x, int x_len,
+		       float *h, int h_len,
+		       float *y, int y_len,
+		       int start, int len,
+		       int step, int offset)
+{
+	if (bounds_check(x_len, h_len, y_len, start, len, step) < 0)
+		return -1;
+
+	memset(y, 0, len * 2 * sizeof(float));
+
+	return _base_convolve_real(x, x_len,
+				   h, h_len,
+				   y, y_len,
+				   start, len, step, offset);
+}
+
+/* API: Non-aligned (no SSE) complex-complex */
+int base_convolve_complex(float *x, int x_len,
+			  float *h, int h_len,
+			  float *y, int y_len,
+			  int start, int len,
+			  int step, int offset)
+{
+	if (bounds_check(x_len, h_len, y_len, start, len, step) < 0)
+		return -1;
+
+	memset(y, 0, len * 2 * sizeof(float));
+
+	return _base_convolve_complex(x, x_len,
+				      h, h_len,
+				      y, y_len,
+				      start, len, step, offset);
+}
+
+/* Aligned filter tap allocation */
+void *convolve_h_alloc(int len)
+{
+#ifdef HAVE_SSE3
+	return memalign(16, len * 2 * sizeof(float));
+#else
+	return malloc(len * 2 * sizeof(float));
+#endif
+}
diff --git a/Transceiver52M/convolve.h b/Transceiver52M/convolve.h
new file mode 100644
index 0000000..aef9953
--- /dev/null
+++ b/Transceiver52M/convolve.h
@@ -0,0 +1,30 @@
+#ifndef _CONVOLVE_H_
+#define _CONVOLVE_H_
+
+void *convolve_h_alloc(int num);
+
+int convolve_real(float *x, int x_len,
+		  float *h, int h_len,
+		  float *y, int y_len,
+		  int start, int len,
+		  int step, int offset);
+
+int convolve_complex(float *x, int x_len,
+		     float *h, int h_len,
+		     float *y, int y_len,
+		     int start, int len,
+		     int step, int offset);
+
+int base_convolve_real(float *x, int x_len,
+		       float *h, int h_len,
+		       float *y, int y_len,
+		       int start, int len,
+		       int step, int offset);
+
+int base_convolve_complex(float *x, int x_len,
+			  float *h, int h_len,
+			  float *y, int y_len,
+			  int start, int len,
+			  int step, int offset);
+
+#endif /* _CONVOLVE_H_ */
diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index 2ccc714..8237aa5 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -29,6 +29,10 @@
 
 using namespace GSM;
 
+extern "C" {
+#include "convolve.h"
+}
+
 #define TABLESIZE 1024
 
 /** Lookup tables for trigonometric approximation */
@@ -45,28 +49,35 @@ signalVector *GMSKRotation = NULL;
 signalVector *GMSKReverseRotation = NULL;
 
 /*
- * RACH and midamble correlation waveforms
+ * RACH and midamble correlation waveforms. Store the buffer separately
+ * because we need to allocate it explicitly outside of the signal vector
+ * constructor. This is because C++ (prior to C++11) is unable to natively
+ * perform 16-byte memory alignment required by many SSE instructions.
  */
 struct CorrelationSequence {
-  CorrelationSequence() : sequence(NULL)
+  CorrelationSequence() : sequence(NULL), buffer(NULL)
   {
   }
 
   ~CorrelationSequence()
   {
     delete sequence;
+    free(buffer);
   }
 
   signalVector *sequence;
+  void         *buffer;
   float        TOA;
   complex      gain;
 };
 
 /*
- * Gaussian and empty modulation pulses
+ * Gaussian and empty modulation pulses. Like the correlation sequences,
+ * store the runtime (Gaussian) buffer separately because of needed alignment
+ * for SSE instructions.
  */
 struct PulseSequence {
-  PulseSequence() : gaussian(NULL), empty(NULL)
+  PulseSequence() : gaussian(NULL), empty(NULL), buffer(NULL)
   {
   }
 
@@ -74,10 +85,12 @@ struct PulseSequence {
   {
     delete gaussian;
     delete empty;
+    free(buffer);
   }
 
   signalVector *gaussian;
   signalVector *empty;
+  void         *buffer;
 };
 
 CorrelationSequence *gMidambles[] = {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
@@ -246,7 +259,7 @@ void initGMSKRotationTables(int sps)
 
 bool sigProcLibSetup(int sps)
 {
-  if ((sps != 0) && (sps != 2) && (sps != 4))
+  if ((sps != 1) && (sps != 2) && (sps != 4))
     return false;
 
   initTrigTables();
@@ -295,174 +308,106 @@ void GMSKReverseRotate(signalVector &x) {
   }
 }
 
-
-signalVector* convolve(const signalVector *a,
-		       const signalVector *b,
-		       signalVector *c,
-		       ConvType spanType,
-		       unsigned startIx,
-		       unsigned len)
+signalVector *convolve(const signalVector *x,
+                        const signalVector *h,
+                        signalVector *y,
+                        ConvType spanType, int start,
+                        unsigned len, unsigned step, int offset)
 {
-  if ((a==NULL) || (b==NULL)) return NULL; 
-  int La = a->size();
-  int Lb = b->size();
-
-  int startIndex;
-  unsigned int outSize;
-  switch (spanType) {
-    case FULL_SPAN:
-      startIndex = 0;
-      outSize = La+Lb-1;
-      break;
-    case OVERLAP_ONLY:
-      startIndex = La;
-      outSize = abs(La-Lb)+1;
-      break;
-    case START_ONLY:
-      startIndex = 0;
-      outSize = La;
-      break;
-    case WITH_TAIL:
-      startIndex = Lb;
-      outSize = La;
-      break;
-    case NO_DELAY:
-      if (Lb % 2) 
-	startIndex = Lb/2;
-      else
-	startIndex = Lb/2-1;
-      outSize = La;
-      break;
-    case CUSTOM:
-      startIndex = startIx;
-      outSize = len;
-      break;
-    default:
-      return NULL;
-  }
+  int rc, head = 0, tail = 0;
+  bool alloc = false, append = false;
+  const signalVector *_x = NULL;
 
-  
-  if (c==NULL)
-    c = new signalVector(outSize);
-  else if (c->size()!=outSize)
+  if (!x || !h)
     return NULL;
 
-  signalVector::const_iterator aStart = a->begin();
-  signalVector::const_iterator bStart = b->begin();
-  signalVector::const_iterator aEnd = a->end();
-  signalVector::const_iterator bEnd = b->end();
-  signalVector::iterator cPtr = c->begin();
-  int t = startIndex;
-  int stopIndex = startIndex + outSize;
-  switch (b->getSymmetry()) {
-  case NONE:
-    {
-      while (t < stopIndex) {
-	signalVector::const_iterator aP = aStart+t;
-	signalVector::const_iterator bP = bStart;
-	if (a->isRealOnly() && b->isRealOnly()) {
-	  float sum = 0.0;
-	  while (bP < bEnd) {
-	    if (aP < aStart) break;
-	    if (aP < aEnd) sum += (aP->real())*(bP->real());
-	    aP--;
-	    bP++;
-	  }
-	  *cPtr++ = sum;
-	}
-	else if (a->isRealOnly()) {
-	  complex sum = 0.0;
-	  while (bP < bEnd) {
-	    if (aP < aStart) break;
-	    if (aP < aEnd) sum += (*bP)*(aP->real());
-	    aP--;
-	    bP++;
-	  }
-	  *cPtr++ = sum;
-	}
-	else if (b->isRealOnly()) {
-	  complex sum = 0.0;
-	  while (bP < bEnd) {
-	    if (aP < aStart) break;
-	    if (aP < aEnd) sum += (*aP)*(bP->real());
-	    aP--;
-	    bP++;
-	  }
-	  *cPtr++ = sum;
-	}
-	else {
-	  complex sum = 0.0;
-	  while (bP < bEnd) {
-	    if (aP < aStart) break;
-	    if (aP < aEnd) sum += (*aP)*(*bP);
-	    aP--;
-	    bP++;
-	  }
-	  *cPtr++ = sum;
-	}
-	t++;
-      }
-    }
+  switch (spanType) {
+  case START_ONLY:
+    start = 0;
+    head = h->size();
+    len = x->size();
+    append = true;
     break;
-  case ABSSYM:
-    {
-      complex sum = 0.0;
-      bool isOdd = (bool) (Lb % 2);
-      if (isOdd) 
-	bEnd = bStart + (Lb+1)/2;
-      else 
-	bEnd = bStart + Lb/2;
-      while (t < stopIndex) {
-	signalVector::const_iterator aP = aStart+t;
-	signalVector::const_iterator aPsym = aP-Lb+1;
-	signalVector::const_iterator bP = bStart;
-	sum = 0.0;
-        if (!b->isRealOnly()) {
-	  while (bP < bEnd) {
-	    if (aP < aStart) break;
-	    if (aP == aPsym)
-	      sum+= (*aP)*(*bP);
-	    else if ((aP < aEnd) && (aPsym >= aStart)) 
-	      sum+= ((*aP)+(*aPsym))*(*bP);
-	    else if (aP < aEnd)
-	      sum += (*aP)*(*bP);
-	    else if (aPsym >= aStart)
-	      sum += (*aPsym)*(*bP);
-	    aP--;
-	    aPsym++;
-	    bP++;
-	  }
-        }
-        else {
-          while (bP < bEnd) {
-            if (aP < aStart) break;
-            if (aP == aPsym)
-              sum+= (*aP)*(bP->real());
-            else if ((aP < aEnd) && (aPsym >= aStart))
-              sum+= ((*aP)+(*aPsym))*(bP->real());
-            else if (aP < aEnd)
-              sum += (*aP)*(bP->real());
-            else if (aPsym >= aStart)
-              sum += (*aPsym)*(bP->real());
-            aP--;
-            aPsym++;
-            bP++;
-          }
-        }
-	*cPtr++ = sum;
-	t++;
-      }
+  case NO_DELAY:
+    start = h->size() / 2;
+    head = start;
+    tail = start;
+    len = x->size();
+    append = true;
+    break;
+  case CUSTOM:
+    if (start < h->size() - 1) {
+      head = h->size() - start;
+      append = true;
+    }
+    if (start + len > x->size()) {
+      tail = start + len - x->size();
+      append = true;
     }
     break;
   default:
     return NULL;
-    break;
   }
-    
-    
-  return c;
-}
 
+  /*
+   * Error if the output vector is too small. Create the output vector
+   * if the pointer is NULL.
+   */
+  if (y && (len > y->size()))
+    return NULL;
+  if (!y) {
+    y = new signalVector(len);
+    alloc = true;
+  }
+
+  /* Prepend or post-pend the input vector if the parameters require it */
+  if (append)
+    _x = new signalVector(*x, head, tail);
+  else
+    _x = x;
+
+  /*
+   * Four convovle types:
+   *   1. Complex-Real (aligned)
+   *   2. Complex-Complex (aligned)
+   *   3. Complex-Real (!aligned)
+   *   4. Complex-Complex (!aligned)
+   */
+  if (h->isRealOnly() && h->isAligned()) {
+    rc = convolve_real((float *) _x->begin(), _x->size(),
+                       (float *) h->begin(), h->size(),
+                       (float *) y->begin(), y->size(),
+                       start, len, step, offset);
+  } else if (!h->isRealOnly() && h->isAligned()) {
+    rc = convolve_complex((float *) _x->begin(), _x->size(),
+                          (float *) h->begin(), h->size(),
+                          (float *) y->begin(), y->size(),
+                          start, len, step, offset);
+  } else if (h->isRealOnly() && !h->isAligned()) {
+    rc = base_convolve_real((float *) _x->begin(), _x->size(),
+                            (float *) h->begin(), h->size(),
+                            (float *) y->begin(), y->size(),
+                            start, len, step, offset);
+  } else if (!h->isRealOnly() && !h->isAligned()) {
+    rc = base_convolve_complex((float *) _x->begin(), _x->size(),
+                               (float *) h->begin(), h->size(),
+                               (float *) y->begin(), y->size(),
+                               start, len, step, offset);
+  } else {
+    rc = -1;
+  }
+
+  if (append)
+    delete _x;
+
+  if (rc < 0) {
+    if (alloc)
+      delete y;
+    return NULL;
+  }
+
+  return y;
+}
 
 void generateGSMPulse(int sps, int symbolLength)
 {
@@ -477,9 +422,17 @@ void generateGSMPulse(int sps, int symbolLength)
   GSMPulse->empty->isRealOnly(true);
   *(GSMPulse->empty->begin()) = 1.0f;
 
+  len = sps * symbolLength;
+  if (len < 4)
+    len = 4;
+
   /* GSM pulse approximation */
-  GSMPulse->gaussian = new signalVector(len);
+  GSMPulse->buffer = convolve_h_alloc(len);
+  GSMPulse->gaussian = new signalVector((complex *)
+                                        GSMPulse->buffer, 0, len);
+  GSMPulse->gaussian->setAligned(true);
   GSMPulse->gaussian->isRealOnly(true);
+
   signalVector::iterator xP = GSMPulse->gaussian->begin();
 
   center = (float) (len - 1.0) / 2.0;
@@ -560,31 +513,6 @@ signalVector* reverseConjugate(signalVector *b)
     return tmp;
 }
 
-signalVector* correlate(signalVector *a,
-			signalVector *b,
-			signalVector *c,
-			ConvType spanType,
-			bool bReversedConjugated,
-		        unsigned startIx,
-			unsigned len)
-{
-  signalVector *tmp = NULL;
-
-  if (!bReversedConjugated) {
-    tmp = reverseConjugate(b);
-  }
-  else {
-    tmp = b;
-  }
-
-  c = convolve(a,tmp,c,spanType,startIx,len);
-
-  if (!bReversedConjugated) delete tmp;
-
-  return c;
-}
-
-
 /* soft output slicer */
 bool vectorSlicer(signalVector *x) 
 {
@@ -599,12 +527,13 @@ bool vectorSlicer(signalVector *x)
   }
   return true;
 }
-  
+
+/* Assume input bits are not differentially encoded */
 signalVector *modulateBurst(const BitVector &wBurst, int guardPeriodLength,
 			    int sps, bool emptyPulse)
 {
   int burstLen;
-  signalVector *pulse, modBurst;
+  signalVector *pulse, *shapedBurst, modBurst;
   signalVector::iterator modBurstItr;
 
   if (emptyPulse)
@@ -628,7 +557,9 @@ signalVector *modulateBurst(const BitVector &wBurst, int guardPeriodLength,
   modBurst.isRealOnly(false);
 
   // filter w/ pulse shape
-  signalVector *shapedBurst = convolve(&modBurst, pulse, NULL, NO_DELAY);
+  shapedBurst = convolve(&modBurst, pulse, NULL, START_ONLY);
+  if (!shapedBurst)
+    return NULL;
 
   return shapedBurst;
 }
@@ -639,24 +570,24 @@ float sinc(float x)
   return 1.0F;
 }
 
-void delayVector(signalVector &wBurst,
-		 float delay)
+bool delayVector(signalVector &wBurst, float delay)
 {
   
   int   intOffset = (int) floor(delay);
   float fracOffset = delay - intOffset;
-  
+
   // do fractional shift first, only do it for reasonable offsets
   if (fabs(fracOffset) > 1e-2) {
     // create sinc function
     signalVector sincVector(21); 
     sincVector.isRealOnly(true);
-    signalVector::iterator sincBurstItr = sincVector.begin();
+    signalVector::iterator sincBurstItr = sincVector.end();
     for (int i = 0; i < 21; i++) 
-      *sincBurstItr++ = (complex) sinc(M_PI_F*(i-10-fracOffset));
+      *--sincBurstItr = (complex) sinc(M_PI_F*(i-10-fracOffset));
   
     signalVector shiftedBurst(wBurst.size());
-    convolve(&wBurst,&sincVector,&shiftedBurst,NO_DELAY);
+    if (!convolve(&wBurst, &sincVector, &shiftedBurst, NO_DELAY))
+      return false;
     wBurst.clone(shiftedBurst);
   }
 
@@ -861,25 +792,25 @@ bool generateMidamble(int sps, int tsc)
   bool status = true;
   complex *data = NULL;
   signalVector *autocorr = NULL, *midamble = NULL;
-  signalVector *midMidamble = NULL;
+  signalVector *midMidamble = NULL, *_midMidamble = NULL;
 
-  if ((tsc < 0) || (tsc > 7)) 
+  if ((tsc < 0) || (tsc > 7))
     return false;
 
   delete gMidambles[tsc];
- 
+
   /* Use middle 16 bits of each TSC. Correlation sequence is not pulse shaped */
   midMidamble = modulateBurst(gTrainingSequence[tsc].segment(5,16), 0, sps, true);
   if (!midMidamble)
     return false;
 
-  /* Simulated receive sequence is pulse shaped */ 
+  /* Simulated receive sequence is pulse shaped */
   midamble = modulateBurst(gTrainingSequence[tsc], 0, sps, false);
   if (!midamble) {
     status = false;
     goto release;
   }
- 
+
   // NOTE: Because ideal TSC 16-bit midamble is 66 symbols into burst,
   //       the ideal TSC has an + 180 degree phase shift,
   //       due to the pi/2 frequency shift, that 
@@ -890,22 +821,32 @@ bool generateMidamble(int sps, int tsc)
 
   conjugateVector(*midMidamble);
 
-  autocorr = correlate(midamble, midMidamble, NULL, NO_DELAY);
+  /* For SSE alignment, reallocate the midamble sequence on 16-byte boundary */
+  data = (complex *) convolve_h_alloc(midMidamble->size());
+  _midMidamble = new signalVector(data, 0, midMidamble->size());
+  _midMidamble->setAligned(true);
+  memcpy(_midMidamble->begin(), midMidamble->begin(),
+	 midMidamble->size() * sizeof(complex));
+
+  autocorr = convolve(midamble, _midMidamble, NULL, NO_DELAY);
   if (!autocorr) {
     status = false;
     goto release;
   }
 
   gMidambles[tsc] = new CorrelationSequence;
-  gMidambles[tsc]->sequence = midMidamble;
-  gMidambles[tsc]->gain = peakDetect(*autocorr,&gMidambles[tsc]->TOA,NULL);
+  gMidambles[tsc]->buffer = data;
+  gMidambles[tsc]->sequence = _midMidamble;
+  gMidambles[tsc]->gain = peakDetect(*autocorr,&gMidambles[tsc]->TOA, NULL);
 
 release:
   delete autocorr;
   delete midamble;
+  delete midMidamble;
 
   if (!status) {
-    delete midMidamble;
+    delete _midMidamble;
+    free(data);
     gMidambles[tsc] = NULL;
   }
 
@@ -917,7 +858,7 @@ bool generateRACHSequence(int sps)
   bool status = true;
   complex *data = NULL;
   signalVector *autocorr = NULL;
-  signalVector *seq0 = NULL, *seq1 = NULL;
+  signalVector *seq0 = NULL, *seq1 = NULL, *_seq1 = NULL;
 
   delete gRACHSequence;
 
@@ -933,74 +874,100 @@ bool generateRACHSequence(int sps)
 
   conjugateVector(*seq1);
 
-  autocorr = new signalVector(seq0->size());
-  if (!convolve(seq0, seq1, autocorr, NO_DELAY)) {
+  /* For SSE alignment, reallocate the midamble sequence on 16-byte boundary */
+  data = (complex *) convolve_h_alloc(seq1->size());
+  _seq1 = new signalVector(data, 0, seq1->size());
+  _seq1->setAligned(true);
+  memcpy(_seq1->begin(), seq1->begin(), seq1->size() * sizeof(complex));
+
+  autocorr = convolve(seq0, _seq1, autocorr, NO_DELAY);
+  if (!autocorr) {
     status = false;
     goto release;
   }
 
   gRACHSequence = new CorrelationSequence;
-  gRACHSequence->sequence = seq1;
-  gRACHSequence->gain = peakDetect(*autocorr,&gRACHSequence->TOA,NULL);
+  gRACHSequence->sequence = _seq1;
+  gRACHSequence->buffer = data;
+  gRACHSequence->gain = peakDetect(*autocorr,&gRACHSequence->TOA, NULL);
 
 release:
   delete autocorr;
   delete seq0;
+  delete seq1;
 
   if (!status) {
-    delete seq1;
+    delete _seq1;
+    free(data);
     gRACHSequence = NULL;
   }
 
   return status;
 }
-				
-bool detectRACHBurst(signalVector &rxBurst,
-		     float detectThreshold,
-		     int sps,
-		     complex *amplitude,
-		     float* TOA)
-{
 
-  //static complex staticData[500];
- 
-  //signalVector correlatedRACH(staticData,0,rxBurst.size());
-  signalVector correlatedRACH(rxBurst.size());
-  correlate(&rxBurst,gRACHSequence->sequence,&correlatedRACH,NO_DELAY,true);
+int detectRACHBurst(signalVector &rxBurst,
+		    float thresh,
+		    int sps,
+		    complex *amp,
+		    float *toa)
+{
+  int start, len, num = 0;
+  float _toa, rms, par, avg = 0.0f;
+  complex _amp, *peak;
+  signalVector corr, *sync = gRACHSequence->sequence;
 
-  float meanPower;
-  complex peakAmpl = peakDetect(correlatedRACH,TOA,&meanPower);
+  if ((sps != 1) && (sps != 2) && (sps != 4))
+    return -1;
 
-  float valleyPower = 0.0; 
+  start = 40 * sps;
+  len = 24 * sps;
+  corr = signalVector(len);
 
-  // check for bogus results
-  if ((*TOA < 0.0) || (*TOA > correlatedRACH.size())) {
-        *amplitude = 0.0;
-	return false;
+  if (!convolve(&rxBurst, sync, &corr,
+                CUSTOM, start, len, sps, 0)) {
+    return -1;
   }
-  complex *peakPtr = correlatedRACH.begin() + (int) rint(*TOA);
 
-  float numSamples = 0.0;
-  for (int i = 57 * sps; i <= 107 * sps; i++) {
-    if (peakPtr+i >= correlatedRACH.end())
-      break;
-    valleyPower += (peakPtr+i)->norm2();
-    numSamples++;
-  }
+  _amp = peakDetect(corr, &_toa, NULL);
+  if ((_toa < 3) || (_toa > len - 3))
+    goto notfound;
 
-  if (numSamples < 2) {
-        *amplitude = 0.0;
-        return false;
+  peak = corr.begin() + (int) rint(_toa);
+
+  for (int i = 2 * sps; i <= 5 * sps; i++) {
+    if (peak - i >= corr.begin()) {
+      avg += (peak - i)->norm2();
+      num++;
+    }
+    if (peak + i < corr.end()) {
+      avg += (peak + i)->norm2();
+      num++;
+    }
   }
 
-  float RMS = sqrtf(valleyPower/(float) numSamples)+0.00001;
-  float peakToMean = peakAmpl.abs()/RMS;
+  if (num < 2)
+    goto notfound;
+
+  rms = sqrtf(avg / (float) num) + 0.00001;
+  par = _amp.abs() / rms;
+  if (par < thresh)
+    goto notfound;
+
+  /* Subtract forward tail bits from delay */
+  if (toa)
+    *toa = _toa - 8 * sps;
+  if (amp)
+    *amp = _amp / gRACHSequence->gain;
 
-  *amplitude = peakAmpl/(gRACHSequence->gain);
+  return 1;
 
-  *TOA = (*TOA) - gRACHSequence->TOA - 8 * sps;
+notfound:
+  if (amp)
+    *amp = 0.0f;
+  if (toa)
+    *toa = 0.0f;
 
-  return (peakToMean > detectThreshold);
+  return 0;
 }
 
 bool energyDetect(signalVector &rxBurst,
@@ -1020,120 +987,95 @@ bool energyDetect(signalVector &rxBurst,
   if (avgPwr) *avgPwr = energy/windowLength;
   return (energy/windowLength > detectThreshold*detectThreshold);
 }
-  
 
-bool analyzeTrafficBurst(signalVector &rxBurst,
-			 unsigned TSC,
-			 float detectThreshold,
-			 int sps,
-			 complex *amplitude,
-			 float *TOA,
-			 unsigned maxTOA,
-                         bool requestChannel,
-                         signalVector **channelResponse,
-			 float *channelResponseOffset) 
+int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
+                        int sps, complex *amp, float *toa, unsigned max_toa,
+                        bool chan_req, signalVector **chan, float *chan_offset)
 {
+  int start, target, len, num = 0;
+  complex _amp, *peak;
+  float _toa, rms, par, avg = 0.0f;
+  signalVector corr, *sync, *_chan;
 
-  assert(TSC<8);
-  assert(amplitude);
-  assert(TOA);
-  assert(gMidambles[TSC]);
-
-  if (maxTOA < 3*sps) maxTOA = 3*sps;
-  unsigned spanTOA = maxTOA;
-  if (spanTOA < 5*sps) spanTOA = 5*sps;
+  if ((tsc < 0) || (tsc > 7) || ((sps != 1) && (sps != 2) && (sps != 4)))
+    return -1;
 
-  unsigned startIx = 66*sps-spanTOA;
-  unsigned endIx = (66+16)*sps+spanTOA;
-  unsigned windowLen = endIx - startIx;
-  unsigned corrLen = 2*maxTOA+1;
+  target = 3 + 58 + 5 + 16;
+  start = (target - 8) * sps;
+  len = (8 + 8 + max_toa) * sps;
 
-  unsigned expectedTOAPeak = (unsigned) round(gMidambles[TSC]->TOA + (gMidambles[TSC]->sequence->size()-1)/2);
+  sync = gMidambles[tsc]->sequence;
+  sync = gMidambles[tsc]->sequence;
+  corr = signalVector(len);
 
-  signalVector burstSegment(rxBurst.begin(),startIx,windowLen);
-
-  //static complex staticData[200];
-  //signalVector correlatedBurst(staticData,0,corrLen);
-  signalVector correlatedBurst(corrLen);
-  correlate(&burstSegment, gMidambles[TSC]->sequence,
-					    &correlatedBurst, CUSTOM,true,
-					    expectedTOAPeak-maxTOA,corrLen);
+  if (!convolve(&rxBurst, sync, &corr,
+                CUSTOM, start, len, sps, 0)) {
+    return -1;
+  }
 
-  float meanPower;
-  *amplitude = peakDetect(correlatedBurst,TOA,&meanPower);
-  float valleyPower = 0.0; //amplitude->norm2();
-  complex *peakPtr = correlatedBurst.begin() + (int) rint(*TOA);
+  _amp = peakDetect(corr, &_toa, NULL);
+  peak = corr.begin() + (int) rint(_toa);
 
-  // check for bogus results
-  if ((*TOA < 0.0) || (*TOA > correlatedBurst.size())) {
-        *amplitude = 0.0;
-        return false;
-  }
+  /* Check for bogus results */
+  if ((_toa < 0.0) || (_toa > corr.size()))
+    goto notfound;
 
-  int numRms = 0;
-  for (int i = 2*sps; i <= 5*sps;i++) {
-    if (peakPtr - i >= correlatedBurst.begin()) { 
-      valleyPower += (peakPtr-i)->norm2();
-      numRms++;
+  for (int i = 2 * sps; i <= 5 * sps; i++) {
+    if (peak - i >= corr.begin()) {
+      avg += (peak - i)->norm2();
+      num++;
     }
-    if (peakPtr + i < correlatedBurst.end()) {
-      valleyPower += (peakPtr+i)->norm2();
-      numRms++;
+    if (peak + i < corr.end()) {
+      avg += (peak + i)->norm2();
+      num++;
     }
   }
 
-  if (numRms < 2) {
-        // check for bogus results
-        *amplitude = 0.0;
-        return false;
-  }
+  if (num < 2)
+    goto notfound;
 
-  float RMS = sqrtf(valleyPower/(float)numRms)+0.00001;
-  float peakToMean = (amplitude->abs())/RMS;
+  rms = sqrtf(avg / (float) num) + 0.00001;
+  par = (_amp.abs()) / rms;
+  if (par < thresh)
+    goto notfound;
 
-  // NOTE: Because ideal TSC is 66 symbols into burst,
-  //       the ideal TSC has an +/- 180 degree phase shift,
-  //       due to the pi/4 frequency shift, that 
-  //       needs to be accounted for.
-  
-  *amplitude = (*amplitude)/gMidambles[TSC]->gain;
-  *TOA = (*TOA) - (maxTOA); 
-
-  if (requestChannel && (peakToMean > detectThreshold)) {
-    float TOAoffset = maxTOA;
-    delayVector(correlatedBurst,-(*TOA));
-    // midamble only allows estimation of a 6-tap channel
-    signalVector chanVector(6 * sps);
-    float maxEnergy = -1.0;
-    int maxI = -1;
-    for (int i = 0; i < 7; i++) {
-      if (TOAoffset + (i-5) * sps + chanVector.size() > correlatedBurst.size())
-        continue;
-      if (TOAoffset + (i-5) * sps < 0)
-        continue;
-      correlatedBurst.segmentCopyTo(chanVector,
-                                    (int) floor(TOAoffset + (i - 5) * sps),
-                                    chanVector.size());
-      float energy = vectorNorm2(chanVector);
-      if (energy > 0.95*maxEnergy) {
-	maxI = i;
-	maxEnergy = energy;
-      }
-    }
-	
-    *channelResponse = new signalVector(chanVector.size());
-    correlatedBurst.segmentCopyTo(**channelResponse,
-                                  (int) floor(TOAoffset + (maxI - 5) * sps),
-                                  (*channelResponse)->size());
-    scaleVector(**channelResponse, complex(1.0, 0.0) / gMidambles[TSC]->gain);
-    
-    if (channelResponseOffset) 
-      *channelResponseOffset = 5 * sps - maxI;
-      
+  /*
+   *  NOTE: Because ideal TSC is 66 symbols into burst,
+   *      the ideal TSC has an +/- 180 degree phase shift,
+   *      due to the pi/4 frequency shift, that 
+   *      needs to be accounted for.
+   */
+  if (amp)
+    *amp = _amp / gMidambles[tsc]->gain;
+
+  /* Delay one half of peak-centred correlation length */
+  _toa -= sps * 8;
+
+  if (toa)
+    *toa = _toa;
+
+  if (chan_req) {
+    _chan = new signalVector(6 * sps);
+
+    delayVector(corr, -_toa);
+    corr.segmentCopyTo(*_chan, target - 3, _chan->size());
+    scaleVector(*_chan, complex(1.0, 0.0) / gMidambles[tsc]->gain);
+
+    *chan = _chan;
+
+    if (chan_offset)
+      *chan_offset = 3.0 * sps;;
   }
 
-  return (peakToMean > detectThreshold);
-		  
+  return 1;
+
+notfound:
+  if (amp)
+    *amp = 0.0f;
+  if (toa)
+    *toa = 0.0f;
+
+  return 0;
 }
 
 signalVector *decimateVector(signalVector &wVector,
@@ -1452,7 +1394,7 @@ bool designDFE(signalVector &channelResponse,
   }
 
   *feedForwardFilter = new signalVector(Nf);
-  signalVector::iterator w = (*feedForwardFilter)->begin();
+  signalVector::iterator w = (*feedForwardFilter)->end();
   for (int i = 0; i < Nf; i++) {
     delete L[i];
     complex w_i = 0.0;
@@ -1463,8 +1405,7 @@ bool designDFE(signalVector &channelResponse,
       w_i += (*vPtr)*(chanPtr->conj());
       vPtr++; chanPtr++;
     }
-    *w = w_i/d;
-    w++;
+    *--w = w_i/d;
   }
 
 
@@ -1479,10 +1420,15 @@ SoftVector *equalizeBurst(signalVector &rxBurst,
 		       signalVector &w, // feedforward filter
 		       signalVector &b) // feedback filter
 {
+  signalVector *postForwardFull;
 
-  delayVector(rxBurst,-TOA);
+  if (!delayVector(rxBurst, -TOA))
+    return NULL;
 
-  signalVector* postForwardFull = convolve(&rxBurst,&w,NULL,FULL_SPAN);
+  postForwardFull = convolve(&rxBurst, &w, NULL,
+                             CUSTOM, 0, rxBurst.size() + w.size() - 1);
+  if (!postForwardFull)
+    return NULL;
 
   signalVector* postForward = new signalVector(rxBurst.size());
   postForwardFull->segmentCopyTo(*postForward,w.size()-1,rxBurst.size());
diff --git a/Transceiver52M/sigProcLib.h b/Transceiver52M/sigProcLib.h
index ee152d5..194002f 100644
--- a/Transceiver52M/sigProcLib.h
+++ b/Transceiver52M/sigProcLib.h
@@ -27,13 +27,10 @@ enum Symmetry {
 
 /** Convolution type indicator */
 enum ConvType {
-  FULL_SPAN = 0,
-  OVERLAP_ONLY = 1,
-  START_ONLY = 2,
-  WITH_TAIL = 3,
-  NO_DELAY = 4,
-  CUSTOM = 5,
-  UNDEFINED = 255
+  START_ONLY,
+  NO_DELAY,
+  CUSTOM,
+  UNDEFINED,
 };
 
 /** the core data structure of the Transceiver */
@@ -44,13 +41,14 @@ class signalVector: public Vector<complex>
   
   Symmetry symmetry;   ///< the symmetry of the vector
   bool realOnly;       ///< true if vector is real-valued, not complex-valued
-  
+  bool aligned;
+ 
  public:
   
   /** Constructors */
   signalVector(int dSize=0, Symmetry wSymmetry = NONE):
     Vector<complex>(dSize),
-    realOnly(false)
+    realOnly(false), aligned(false)
     { 
       symmetry = wSymmetry; 
     };
@@ -58,26 +56,45 @@ class signalVector: public Vector<complex>
   signalVector(complex* wData, size_t start, 
 	       size_t span, Symmetry wSymmetry = NONE):
     Vector<complex>(NULL,wData+start,wData+start+span),
-    realOnly(false)
+    realOnly(false), aligned(false)
     { 
       symmetry = wSymmetry; 
     };
       
   signalVector(const signalVector &vec1, const signalVector &vec2):
     Vector<complex>(vec1,vec2),
-    realOnly(false)
+    realOnly(false), aligned(false)
     { 
       symmetry = vec1.symmetry; 
     };
 	
   signalVector(const signalVector &wVector):
     Vector<complex>(wVector.size()),
-    realOnly(false)
+    realOnly(false), aligned(false)
     {
       wVector.copyTo(*this); 
       symmetry = wVector.getSymmetry();
     };
 
+  signalVector(size_t size, size_t start):
+    Vector<complex>(size + start),
+    realOnly(false), aligned(false)
+    {
+      mStart = mData + start;
+      symmetry = NONE;
+    };
+
+  signalVector(const signalVector &wVector, size_t start, size_t tail = 0):
+    Vector<complex>(start + wVector.size() + tail),
+    realOnly(false), aligned(false)
+    {
+      mStart = mData + start;
+      wVector.copyTo(*this);
+      memset(mData, 0, start * sizeof(complex));
+      memset(mStart + wVector.size(), 0, tail * sizeof(complex));
+      symmetry = NONE;
+    };
+
   /** symmetry operators */
   Symmetry getSymmetry() const { return symmetry;};
   void setSymmetry(Symmetry wSymmetry) { symmetry = wSymmetry;}; 
@@ -85,6 +102,10 @@ class signalVector: public Vector<complex>
   /** real-valued operators */
   bool isRealOnly() const { return realOnly;};
   void isRealOnly(bool wOnly) { realOnly = wOnly;};
+
+  /** alignment markers */
+  bool isAligned() const { return aligned; };
+  void setAligned(bool aligned) { this->aligned = aligned; };
 };
 
 /** Convert a linear number to a dB value */
@@ -110,14 +131,15 @@ void sigProcLibDestroy(void);
 	@param a,b The vectors to be convolved.
 	@param c, A preallocated vector to hold the convolution result.
 	@param spanType The type/span of the convolution.
-	@return The convolution result.
+	@return The convolution result or NULL on error.
 */
-signalVector* convolve(const signalVector *a,
-		       const signalVector *b,
-		       signalVector *c,
-		       ConvType spanType,
-		       unsigned startIx = 0,
-		       unsigned len = 0);
+signalVector *convolve(const signalVector *a,
+                       const signalVector *b,
+                       signalVector *c,
+                       ConvType spanType,
+                       int start = 0,
+                       unsigned len = 0,
+                       unsigned step = 1, int offset = 0);
 
 /** 
 	Generate the GSM pulse. 
@@ -169,8 +191,7 @@ signalVector *modulateBurst(const BitVector &wBurst,
 float sinc(float x);
 
 /** Delay a vector */
-void delayVector(signalVector &wBurst,
-		 float delay);
+bool delayVector(signalVector &wBurst, float delay);
 
 /** Add two vectors in-place */
 bool addVector(signalVector &x,
@@ -257,13 +278,13 @@ bool energyDetect(signalVector &rxBurst,
         @param sps The number of samples per GSM symbol.
         @param amplitude The estimated amplitude of received RACH burst.
         @param TOA The estimate time-of-arrival of received RACH burst.
-        @return True if burst SNR is larger that the detectThreshold value.
+        @return positive if threshold value is reached, negative on error, zero otherwise
 */
-bool detectRACHBurst(signalVector &rxBurst,
-		     float detectThreshold,
-		     int sps,
-		     complex *amplitude,
-		     float* TOA);
+int detectRACHBurst(signalVector &rxBurst,
+                    float detectThreshold,
+                    int sps,
+                    complex *amplitude,
+                    float* TOA);
 
 /**
         Normal burst correlator, detector, channel estimator.
@@ -277,18 +298,18 @@ bool detectRACHBurst(signalVector &rxBurst,
         @param requestChannel Set to true if channel estimation is desired.
         @param channelResponse The estimated channel.
         @param channelResponseOffset The time offset b/w the first sample of the channel response and the reported TOA.
-        @return True if burst SNR is larger that the detectThreshold value.
+        @return positive if threshold value is reached, negative on error, zero otherwise
 */
-bool analyzeTrafficBurst(signalVector &rxBurst,
-			 unsigned TSC,
-			 float detectThreshold,
-			 int sps,
-			 complex *amplitude,
-			 float *TOA,
-                         unsigned maxTOA,
-                         bool requestChannel = false,
-			 signalVector** channelResponse = NULL,
-			 float *channelResponseOffset = NULL);
+int analyzeTrafficBurst(signalVector &rxBurst,
+			unsigned TSC,
+			float detectThreshold,
+			int sps,
+			complex *amplitude,
+			float *TOA,
+                        unsigned maxTOA,
+                        bool requestChannel = false,
+			signalVector** channelResponse = NULL,
+			float *channelResponseOffset = NULL);
 
 /**
 	Decimate a vector.
diff --git a/Transceiver52M/sigProcLibTest.cpp b/Transceiver52M/sigProcLibTest.cpp
index 4f92717..32661f4 100644
--- a/Transceiver52M/sigProcLibTest.cpp
+++ b/Transceiver52M/sigProcLibTest.cpp
@@ -50,9 +50,6 @@ int main(int argc, char **argv) {
 
   sigProcLibSetup(samplesPerSymbol);
   
-  signalVector *gsmPulse = generateGSMPulse(2,samplesPerSymbol);
-  cout << *gsmPulse << endl;
-
   BitVector RACHBurstStart = "01010101";
   BitVector RACHBurstRest = "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000";
 
@@ -60,12 +57,9 @@ int main(int argc, char **argv) {
  
 
   signalVector *RACHSeq = modulateBurst(RACHBurst,
-                                        *gsmPulse,
                                         9,
                                         samplesPerSymbol);
 
-  generateRACHSequence(*gsmPulse,samplesPerSymbol);
-
   complex a; float t;
   detectRACHBurst(*RACHSeq, 5, samplesPerSymbol,&a,&t); 
 
@@ -94,12 +88,9 @@ int main(int argc, char **argv) {
 
   BitVector normalBurst(BitVector(normalBurstSeg,gTrainingSequence[TSC]),normalBurstSeg);
 
+  generateMidamble(samplesPerSymbol,TSC);
 
-  generateMidamble(*gsmPulse,samplesPerSymbol,TSC);
-
-
-  signalVector *modBurst = modulateBurst(normalBurst,*gsmPulse,
-                                         0,samplesPerSymbol);
+  signalVector *modBurst = modulateBurst(normalBurst,0,samplesPerSymbol);
 
   
   //delayVector(*rsVector2,6.932);
@@ -133,7 +124,7 @@ int main(int argc, char **argv) {
   cout << "ampl:" << ampl << endl;
   cout << "TOA: " << TOA << endl;
   //cout << "chanResp: " << *chanResp << endl;
-  SoftVector *demodBurst = demodulateBurst(*modBurst,*gsmPulse,samplesPerSymbol,(complex) ampl, TOA);
+  SoftVector *demodBurst = demodulateBurst(*modBurst,samplesPerSymbol,(complex) ampl, TOA);
   
   cout << *demodBurst << endl;
 
diff --git a/config/ax_check_compile_flag.m4 b/config/ax_check_compile_flag.m4
new file mode 100644
index 0000000..c3a8d69
--- /dev/null
+++ b/config/ax_check_compile_flag.m4
@@ -0,0 +1,72 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS])
+#
+# DESCRIPTION
+#
+#   Check whether the given FLAG works with the current language's compiler
+#   or gives an error.  (Warnings, however, are ignored)
+#
+#   ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
+#   success/failure.
+#
+#   If EXTRA-FLAGS is defined, it is added to the current language's default
+#   flags (e.g. CFLAGS) when the check is done.  The check is thus made with
+#   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to
+#   force the compiler to issue an error when a bad flag is given.
+#
+#   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
+#   macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   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, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 2
+
+AC_DEFUN([AX_CHECK_COMPILE_FLAG],
+[AC_PREREQ(2.59)dnl for _AC_LANG_PREFIX
+AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
+  ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
+  _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
+    [AS_VAR_SET(CACHEVAR,[yes])],
+    [AS_VAR_SET(CACHEVAR,[no])])
+  _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
+AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes],
+  [m4_default([$2], :)],
+  [m4_default([$3], :)])
+AS_VAR_POPDEF([CACHEVAR])dnl
+])dnl AX_CHECK_COMPILE_FLAGS
diff --git a/config/ax_ext.m4 b/config/ax_ext.m4
new file mode 100644
index 0000000..fbd10cc
--- /dev/null
+++ b/config/ax_ext.m4
@@ -0,0 +1,221 @@
+# ===========================================================================
+#          http://www.gnu.org/software/autoconf-archive/ax_ext.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_EXT
+#
+# DESCRIPTION
+#
+#   Find supported SIMD extensions by requesting cpuid. When an SIMD
+#   extension is found, the -m"simdextensionname" is added to SIMD_FLAGS if
+#   compiler supports it. For example, if "sse2" is available, then "-msse2"
+#   is added to SIMD_FLAGS.
+#
+#   This macro calls:
+#
+#     AC_SUBST(SIMD_FLAGS)
+#
+#   And defines:
+#
+#     HAVE_MMX / HAVE_SSE / HAVE_SSE2 / HAVE_SSE3 / HAVE_SSSE3 / HAVE_SSE4.1 / HAVE_SSE4.2 / HAVE_AVX
+#
+# LICENSE
+#
+#   Copyright (c) 2007 Christophe Tournayre <turn3r@users.sourceforge.net>
+#   Copyright (c) 2013 Michael Petch <mpetch@capp-sysware.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 12
+
+AC_DEFUN([AX_EXT],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  case $host_cpu in
+    i[[3456]]86*|x86_64*|amd64*)
+
+      AC_REQUIRE([AX_GCC_X86_CPUID])
+      AC_REQUIRE([AX_GCC_X86_AVX_XGETBV])
+
+      AX_GCC_X86_CPUID(0x00000001)
+      ecx=`echo $ax_cv_gcc_x86_cpuid_0x00000001 | cut -d ":" -f 3`
+      edx=`echo $ax_cv_gcc_x86_cpuid_0x00000001 | cut -d ":" -f 4`
+
+      AC_CACHE_CHECK([whether mmx is supported], [ax_cv_have_mmx_ext],
+      [
+        ax_cv_have_mmx_ext=no
+        if test "$((0x$edx>>23&0x01))" = 1; then
+          ax_cv_have_mmx_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether sse is supported], [ax_cv_have_sse_ext],
+      [
+        ax_cv_have_sse_ext=no
+        if test "$((0x$edx>>25&0x01))" = 1; then
+          ax_cv_have_sse_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether sse2 is supported], [ax_cv_have_sse2_ext],
+      [
+        ax_cv_have_sse2_ext=no
+        if test "$((0x$edx>>26&0x01))" = 1; then
+          ax_cv_have_sse2_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether sse3 is supported], [ax_cv_have_sse3_ext],
+      [
+        ax_cv_have_sse3_ext=no
+        if test "$((0x$ecx&0x01))" = 1; then
+          ax_cv_have_sse3_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether ssse3 is supported], [ax_cv_have_ssse3_ext],
+      [
+        ax_cv_have_ssse3_ext=no
+        if test "$((0x$ecx>>9&0x01))" = 1; then
+          ax_cv_have_ssse3_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether sse4.1 is supported], [ax_cv_have_sse41_ext],
+      [
+        ax_cv_have_sse41_ext=no
+        if test "$((0x$ecx>>19&0x01))" = 1; then
+          ax_cv_have_sse41_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether sse4.2 is supported], [ax_cv_have_sse42_ext],
+      [
+        ax_cv_have_sse42_ext=no
+        if test "$((0x$ecx>>20&0x01))" = 1; then
+          ax_cv_have_sse42_ext=yes
+        fi
+      ])
+
+      AC_CACHE_CHECK([whether avx is supported by processor], [ax_cv_have_avx_cpu_ext],
+      [
+        ax_cv_have_avx_cpu_ext=no
+        if test "$((0x$ecx>>28&0x01))" = 1; then
+          ax_cv_have_avx_cpu_ext=yes
+        fi
+      ])
+
+      if test x"$ax_cv_have_avx_cpu_ext" = x"yes"; then
+        AX_GCC_X86_AVX_XGETBV(0x00000000)
+
+        xgetbv_eax="0"
+        if test x"$ax_cv_gcc_x86_avx_xgetbv_0x00000000" != x"unknown"; then
+          xgetbv_eax=`echo $ax_cv_gcc_x86_avx_xgetbv_0x00000000 | cut -d ":" -f 1`
+        fi
+
+        AC_CACHE_CHECK([whether avx is supported by operating system], [ax_cv_have_avx_ext],
+        [
+          ax_cv_have_avx_ext=no
+
+          if test "$((0x$ecx>>27&0x01))" = 1; then
+            if test "$((0x$xgetbv_eax&0x6))" = 6; then
+              ax_cv_have_avx_ext=yes
+            fi
+          fi
+        ])
+        if test x"$ax_cv_have_avx_ext" = x"no"; then
+          AC_MSG_WARN([Your processor supports AVX, but your operating system doesn't])
+        fi
+      fi
+
+      if test "$ax_cv_have_mmx_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-mmmx, ax_cv_support_mmx_ext=yes, [])
+        if test x"$ax_cv_support_mmx_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -mmmx"
+          AC_DEFINE(HAVE_MMX,,[Support mmx instructions])
+        else
+          AC_MSG_WARN([Your processor supports mmx instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_sse_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse, ax_cv_support_sse_ext=yes, [])
+        if test x"$ax_cv_support_sse_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -msse"
+          AC_DEFINE(HAVE_SSE,,[Support SSE (Streaming SIMD Extensions) instructions])
+        else
+          AC_MSG_WARN([Your processor supports sse instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_sse2_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse2, ax_cv_support_sse2_ext=yes, [])
+        if test x"$ax_cv_support_sse2_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -msse2"
+          AC_DEFINE(HAVE_SSE2,,[Support SSE2 (Streaming SIMD Extensions 2) instructions])
+        else
+          AC_MSG_WARN([Your processor supports sse2 instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_sse3_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse3, ax_cv_support_sse3_ext=yes, [])
+        if test x"$ax_cv_support_sse3_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -msse3"
+          AC_DEFINE(HAVE_SSE3,,[Support SSE3 (Streaming SIMD Extensions 3) instructions])
+        else
+          AC_MSG_WARN([Your processor supports sse3 instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_ssse3_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-mssse3, ax_cv_support_ssse3_ext=yes, [])
+        if test x"$ax_cv_support_ssse3_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -mssse3"
+          AC_DEFINE(HAVE_SSSE3,,[Support SSSE3 (Supplemental Streaming SIMD Extensions 3) instructions])
+        else
+          AC_MSG_WARN([Your processor supports ssse3 instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_sse41_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse4.1, ax_cv_support_sse41_ext=yes, [])
+        if test x"$ax_cv_support_sse41_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -msse4.1"
+          AC_DEFINE(HAVE_SSE4_1,,[Support SSSE4.1 (Streaming SIMD Extensions 4.1) instructions])
+        else
+          AC_MSG_WARN([Your processor supports sse4.1 instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_sse42_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse4.2, ax_cv_support_sse42_ext=yes, [])
+        if test x"$ax_cv_support_sse42_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -msse4.2"
+          AC_DEFINE(HAVE_SSE4_2,,[Support SSSE4.2 (Streaming SIMD Extensions 4.2) instructions])
+        else
+          AC_MSG_WARN([Your processor supports sse4.2 instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+      if test "$ax_cv_have_avx_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-mavx, ax_cv_support_avx_ext=yes, [])
+        if test x"$ax_cv_support_avx_ext" = x"yes"; then
+          SIMD_FLAGS="$SIMD_FLAGS -mavx"
+          AC_DEFINE(HAVE_AVX,,[Support AVX (Advanced Vector Extensions) instructions])
+        else
+          AC_MSG_WARN([Your processor supports avx instructions but not your compiler, can you try another compiler?])
+        fi
+      fi
+
+  ;;
+  esac
+
+  AC_SUBST(SIMD_FLAGS)
+])
diff --git a/config/ax_gcc_x86_avx_xgetbv.m4 b/config/ax_gcc_x86_avx_xgetbv.m4
new file mode 100644
index 0000000..0624eeb
--- /dev/null
+++ b/config/ax_gcc_x86_avx_xgetbv.m4
@@ -0,0 +1,79 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_avx_xgetbv.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_GCC_X86_AVX_XGETBV
+#
+# DESCRIPTION
+#
+#   On later x86 processors with AVX SIMD support, with gcc or a compiler
+#   that has a compatible syntax for inline assembly instructions, run a
+#   small program that executes the xgetbv instruction with input OP. This
+#   can be used to detect if the OS supports AVX instruction usage.
+#
+#   On output, the values of the eax and edx registers are stored as
+#   hexadecimal strings as "eax:edx" in the cache variable
+#   ax_cv_gcc_x86_avx_xgetbv.
+#
+#   If the xgetbv instruction fails (because you are running a
+#   cross-compiler, or because you are not using gcc, or because you are on
+#   a processor that doesn't have this instruction),
+#   ax_cv_gcc_x86_avx_xgetbv_OP is set to the string "unknown".
+#
+#   This macro mainly exists to be used in AX_EXT.
+#
+# LICENSE
+#
+#   Copyright (c) 2013 Michael Petch <mpetch@capp-sysware.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   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, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 1
+
+AC_DEFUN([AX_GCC_X86_AVX_XGETBV],
+[AC_REQUIRE([AC_PROG_CC])
+AC_LANG_PUSH([C])
+AC_CACHE_CHECK(for x86-AVX xgetbv $1 output, ax_cv_gcc_x86_avx_xgetbv_$1,
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
+     int op = $1, eax, edx;
+     FILE *f;
+      /* Opcodes for xgetbv */
+      __asm__(".byte 0x0f, 0x01, 0xd0"
+        : "=a" (eax), "=d" (edx)
+        : "c" (op));
+     f = fopen("conftest_xgetbv", "w"); if (!f) return 1;
+     fprintf(f, "%x:%x\n", eax, edx);
+     fclose(f);
+     return 0;
+])],
+     [ax_cv_gcc_x86_avx_xgetbv_$1=`cat conftest_xgetbv`; rm -f conftest_xgetbv],
+     [ax_cv_gcc_x86_avx_xgetbv_$1=unknown; rm -f conftest_xgetbv],
+     [ax_cv_gcc_x86_avx_xgetbv_$1=unknown])])
+AC_LANG_POP([C])
+])
diff --git a/config/ax_gcc_x86_cpuid.m4 b/config/ax_gcc_x86_cpuid.m4
new file mode 100644
index 0000000..7d46fee
--- /dev/null
+++ b/config/ax_gcc_x86_cpuid.m4
@@ -0,0 +1,79 @@
+# ===========================================================================
+#     http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_GCC_X86_CPUID(OP)
+#
+# DESCRIPTION
+#
+#   On Pentium and later x86 processors, with gcc or a compiler that has a
+#   compatible syntax for inline assembly instructions, run a small program
+#   that executes the cpuid instruction with input OP. This can be used to
+#   detect the CPU type.
+#
+#   On output, the values of the eax, ebx, ecx, and edx registers are stored
+#   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
+#   ax_cv_gcc_x86_cpuid_OP.
+#
+#   If the cpuid instruction fails (because you are running a
+#   cross-compiler, or because you are not using gcc, or because you are on
+#   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
+#   is set to the string "unknown".
+#
+#   This macro mainly exists to be used in AX_GCC_ARCHFLAG.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2008 Matteo Frigo
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   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, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 7
+
+AC_DEFUN([AX_GCC_X86_CPUID],
+[AC_REQUIRE([AC_PROG_CC])
+AC_LANG_PUSH([C])
+AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
+     int op = $1, eax, ebx, ecx, edx;
+     FILE *f;
+      __asm__("cpuid"
+        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
+        : "a" (op));
+     f = fopen("conftest_cpuid", "w"); if (!f) return 1;
+     fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
+     fclose(f);
+     return 0;
+])],
+     [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
+     [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
+     [ax_cv_gcc_x86_cpuid_$1=unknown])])
+AC_LANG_POP([C])
+])
diff --git a/configure.ac b/configure.ac
index 3cf2783..6ab694d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,6 +22,7 @@ AC_INIT(openbts,P2.8TRUNK)
 AC_PREREQ(2.57)
 AC_CONFIG_SRCDIR([Transceiver52M/Makefile.am])
 AC_CONFIG_AUX_DIR([.])	
+AC_CONFIG_MACRO_DIR([config])
 AM_CONFIG_HEADER(config.h)
 
 AC_CANONICAL_BUILD
@@ -90,11 +91,14 @@ AS_IF([test "x$with_usrp1" = "xyes"], [
     if test "x$libusrp_3_3" = "xyes";then
         AC_DEFINE(HAVE_LIBUSRP_3_3, 1, Define to 1 if you have libusrp >= 3.3)
     fi
+    # Find and define supported SIMD extensions
+    AX_EXT
 ])
 
 AS_IF([test "x$with_uhd" = "xyes"],[
     PKG_CHECK_MODULES(UHD, uhd >= 003.004.000)
     AC_DEFINE(USE_UHD, 1, Define to 1 if using UHD)
+    AX_EXT
 ])
 
 AS_IF([test "x$with_extref" = "xyes"], [