Merge branch 'convert_types' into usrp1

8 files changed, 279 insertions, 93 deletions

diff --git a/host/examples/tx_waveforms.cpp b/host/examples/tx_waveforms.cpp
index e9cf210bb..9886000b1 100644
--- a/host/examples/tx_waveforms.cpp
+++ b/host/examples/tx_waveforms.cpp
@@ -20,19 +20,41 @@
 #include <uhd/usrp/simple_usrp.hpp>
 #include <boost/program_options.hpp>
 #include <boost/thread/thread_time.hpp> //system time
+#include <boost/math/special_functions/round.hpp>
 #include <boost/format.hpp>
+#include <boost/function.hpp>
 #include <iostream>
 #include <complex>
 #include <cmath>
 
 namespace po = boost::program_options;
 
+/***********************************************************************
+ * Waveform generators
+ **********************************************************************/
+float gen_const(float){
+    return 1;
+}
+
+float gen_square(float x){
+    return float((std::fmod(x, 1) < float(0.5))? 0 : 1);
+}
+
+float gen_ramp(float x){
+    return std::fmod(x, 1)*2 - 1;
+}
+
+float gen_sine(float x){
+    static const float two_pi = 2*std::acos(float(-1));
+    return std::sin(x*two_pi);
+}
+
 int UHD_SAFE_MAIN(int argc, char *argv[]){
     uhd::set_thread_priority_safe();
 
     //variables to be set by po
     std::string args, wave_type;
-    size_t total_duration, amspb;
+    size_t total_duration, spb;
     double rate, freq, wave_freq;
     float ampl, gain;
 
@@ -42,7 +64,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){
         ("help", "help message")
         ("args", po::value<std::string>(&args)->default_value(""), "simple uhd device address args")
         ("duration", po::value<size_t>(&total_duration)->default_value(3), "number of seconds to transmit")
-        ("amspb", po::value<size_t>(&amspb)->default_value(10000), "approximate mimimum samples per buffer")
+        ("spb", po::value<size_t>(&spb)->default_value(10000), "samples per buffer")
         ("rate", po::value<double>(&rate)->default_value(100e6/16), "rate of outgoing samples")
         ("freq", po::value<double>(&freq)->default_value(0), "rf center frequency in Hz")
         ("ampl", po::value<float>(&ampl)->default_value(float(0.3)), "amplitude of the waveform")
@@ -88,33 +110,24 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){
     }
 
     //error when the waveform is not possible to generate
-    if (std::abs(wave_freq)/sdev->get_tx_rate() < 0.5/amspb){
-        throw std::runtime_error("wave freq/tx rate too small");
-    }
     if (std::abs(wave_freq) > sdev->get_tx_rate()/2){
         throw std::runtime_error("wave freq out of Nyquist zone");
     }
 
-    //fill a buffer with one period worth of samples
-    std::vector<float> period(size_t(sdev->get_tx_rate()/std::abs(wave_freq)));
-    std::cout << boost::format("Samples per waveform period: %d") % period.size() << std::endl;
-    for (size_t n = 0; n < period.size(); n++){
-        if      (wave_type == "CONST")  period[n] = ampl;
-        else if (wave_type == "SQUARE") period[n] = (n > period.size()/2)? ampl : 0;
-        else if (wave_type == "RAMP")   period[n] = float((n/double(period.size()-1)) * 2*ampl - ampl);
-        else if (wave_type == "SINE")   period[n] = ampl*float(std::sin(2*M_PI*n/double(period.size())));
-        else throw std::runtime_error("unknown waveform type: " + wave_type);
-    }
-
-    //allocate data to send (fill with several periods worth of IQ samples)
-    const size_t periods_per_buff = std::max<size_t>(1, amspb/period.size());
-    std::vector<std::complex<float> > buff(period.size()*periods_per_buff);
-    std::cout << boost::format("Samples per send buffer: %d") % buff.size() << std::endl;
-    const size_t i_ahead = (wave_freq > 0)? period.size()/4 : 0;
-    const size_t q_ahead = (wave_freq < 0)? period.size()/4 : 0;
-    for (size_t n = 0; n < buff.size(); n++) buff[n] = std::complex<float>(
-        period[(n+i_ahead)%period.size()], period[(n+q_ahead)%period.size()] //I,Q
-    );
+    //store the generator function for the selected waveform
+    boost::function<float(float)> wave_gen;
+    if      (wave_type == "CONST")  wave_gen = &gen_const;
+    else if (wave_type == "SQUARE") wave_gen = &gen_square;
+    else if (wave_type == "RAMP")   wave_gen = &gen_ramp;
+    else if (wave_type == "SINE")   wave_gen = &gen_sine;
+    else throw std::runtime_error("unknown waveform type: " + wave_type);
+
+    //allocate the buffer and precalculate values
+    std::vector<std::complex<float> > buff(spb);
+    const float cps = float(wave_freq/sdev->get_tx_rate());
+    const float i_off = (wave_freq > 0)? float(0.25) : 0;
+    const float q_off = (wave_freq < 0)? float(0.25) : 0;
+    float theta = 0;
 
     //setup the metadata flags
     uhd::tx_metadata_t md;
@@ -123,11 +136,27 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){
 
     //send the data in multiple packets
     boost::system_time end_time(boost::get_system_time() + boost::posix_time::seconds(total_duration));
-    while(end_time > boost::get_system_time()) dev->send(
-        &buff.front(), buff.size(), md,
-        uhd::io_type_t::COMPLEX_FLOAT32,
-        uhd::device::SEND_MODE_FULL_BUFF
-    );
+    while(end_time > boost::get_system_time()){
+
+        //fill the buffer with the waveform
+        for (size_t n = 0; n < buff.size(); n++){
+            buff[n] = std::complex<float>(
+                ampl*wave_gen(i_off + theta),
+                ampl*wave_gen(q_off + theta)
+            );
+            theta += cps;
+        }
+
+        //bring the theta back into range [0, 1)
+        theta = std::fmod(theta, 1);
+
+        //send the entire contents of the buffer
+        dev->send(
+            &buff.front(), buff.size(), md,
+            uhd::io_type_t::COMPLEX_FLOAT32,
+            uhd::device::SEND_MODE_FULL_BUFF
+        );
+    }
 
     //send a mini EOB packet
     md.start_of_burst = false;
diff --git a/host/include/uhd/usrp/dboard_iface.hpp b/host/include/uhd/usrp/dboard_iface.hpp
index e776ecc42..c7db244f2 100644
--- a/host/include/uhd/usrp/dboard_iface.hpp
+++ b/host/include/uhd/usrp/dboard_iface.hpp
@@ -148,6 +148,14 @@ public:
     virtual void write_gpio(unit_t unit, boost::uint16_t value) = 0;
 
     /*!
+     * Setup the GPIO debug mux.
+     *
+     * \param unit which unit rx or tx
+     * \param which which debug: 0, 1
+     */
+    virtual void set_gpio_debug(unit_t unit, int which) = 0;
+
+    /*!
      * Read daughterboard GPIO pin values.
      *
      * \param unit which unit rx or tx
diff --git a/host/include/uhd/usrp/simple_usrp.hpp b/host/include/uhd/usrp/simple_usrp.hpp
index 4da63c929..08b9c01ea 100644
--- a/host/include/uhd/usrp/simple_usrp.hpp
+++ b/host/include/uhd/usrp/simple_usrp.hpp
@@ -25,6 +25,7 @@
 #include <uhd/types/clock_config.hpp>
 #include <uhd/types/tune_result.hpp>
 #include <uhd/usrp/subdev_spec.hpp>
+#include <uhd/usrp/dboard_iface.hpp>
 #include <boost/shared_ptr.hpp>
 #include <boost/utility.hpp>
 #include <vector>
@@ -136,6 +137,8 @@ public:
      */
     virtual float read_rssi(void) = 0;
 
+    virtual dboard_iface::sptr get_rx_dboard_iface(void) = 0;
+
     /*******************************************************************
      * TX methods
      ******************************************************************/
@@ -159,6 +162,8 @@ public:
     virtual std::vector<std::string> get_tx_antennas(void) = 0;
 
     virtual bool get_tx_lo_locked(void) = 0;
+
+    virtual dboard_iface::sptr get_tx_dboard_iface(void) = 0;
 };
 
 }}
diff --git a/host/lib/transport/convert_types_impl.hpp b/host/lib/transport/convert_types_impl.hpp
index 5958b08cb..fdc859883 100644
--- a/host/lib/transport/convert_types_impl.hpp
+++ b/host/lib/transport/convert_types_impl.hpp
@@ -28,6 +28,10 @@
     #define USE_EMMINTRIN_H //use sse2 intrinsics
 #endif
 
+#if defined(USE_EMMINTRIN_H)
+    #include <emmintrin.h>
+#endif
+
 /***********************************************************************
  * Typedefs
  **********************************************************************/
@@ -72,7 +76,7 @@ static UHD_INLINE void item32_to_sc16_bswap(
 }
 
 /***********************************************************************
- * Convert complex float buffer to items32
+ * Convert complex float buffer to items32 (no swap)
  **********************************************************************/
 static const float shorts_per_float = float(32767);
 
@@ -82,6 +86,41 @@ static UHD_INLINE item32_t fc32_to_item32(fc32_t num){
     return (item32_t(real) << 16) | (item32_t(imag) << 0);
 }
 
+////////////////////////////////////
+// none-swap
+////////////////////////////////////
+#if defined(USE_EMMINTRIN_H)
+static UHD_INLINE void fc32_to_item32_nswap(
+    const fc32_t *input, item32_t *output, size_t nsamps
+){
+    __m128 scalar = _mm_set_ps1(shorts_per_float);
+
+    //convert blocks of samples with intrinsics
+    size_t i = 0; for (; i < (nsamps & ~0x3); i+=4){
+        //load from input
+        __m128 tmplo = _mm_loadu_ps(reinterpret_cast<const float *>(input+i+0));
+        __m128 tmphi = _mm_loadu_ps(reinterpret_cast<const float *>(input+i+2));
+
+        //convert and scale
+        __m128i tmpilo = _mm_cvtps_epi32(_mm_mul_ps(tmplo, scalar));
+        __m128i tmpihi = _mm_cvtps_epi32(_mm_mul_ps(tmphi, scalar));
+
+        //pack + swap 16-bit pairs
+        __m128i tmpi = _mm_packs_epi32(tmpilo, tmpihi);
+        tmpi = _mm_shufflelo_epi16(tmpi, _MM_SHUFFLE(2, 3, 0, 1));
+        tmpi = _mm_shufflehi_epi16(tmpi, _MM_SHUFFLE(2, 3, 0, 1));
+
+        //store to output
+        _mm_storeu_si128(reinterpret_cast<__m128i *>(output+i), tmpi);
+    }
+
+    //convert remainder
+    for (; i < nsamps; i++){
+        output[i] = fc32_to_item32(input[i]);
+    }
+}
+
+#else
 static UHD_INLINE void fc32_to_item32_nswap(
     const fc32_t *input, item32_t *output, size_t nsamps
 ){
@@ -90,9 +129,12 @@ static UHD_INLINE void fc32_to_item32_nswap(
     }
 }
 
-#if defined(USE_EMMINTRIN_H)
-#include <emmintrin.h>
+#endif
 
+////////////////////////////////////
+// byte-swap
+////////////////////////////////////
+#if defined(USE_EMMINTRIN_H)
 static UHD_INLINE void fc32_to_item32_bswap(
     const fc32_t *input, item32_t *output, size_t nsamps
 ){
@@ -108,7 +150,7 @@ static UHD_INLINE void fc32_to_item32_bswap(
         __m128i tmpilo = _mm_cvtps_epi32(_mm_mul_ps(tmplo, scalar));
         __m128i tmpihi = _mm_cvtps_epi32(_mm_mul_ps(tmphi, scalar));
 
-        //pack + byteswap -> byteswap 32 bit words
+        //pack + byteswap -> byteswap 16 bit words
         __m128i tmpi = _mm_packs_epi32(tmpilo, tmpihi);
         tmpi = _mm_or_si128(_mm_srli_epi16(tmpi, 8), _mm_slli_epi16(tmpi, 8));
 
@@ -145,6 +187,43 @@ static UHD_INLINE fc32_t item32_to_fc32(item32_t item){
     );
 }
 
+////////////////////////////////////
+// none-swap
+////////////////////////////////////
+#if defined(USE_EMMINTRIN_H)
+static UHD_INLINE void item32_to_fc32_nswap(
+    const item32_t *input, fc32_t *output, size_t nsamps
+){
+    __m128 scalar = _mm_set_ps1(floats_per_short/(1 << 16));
+    __m128i zeroi = _mm_setzero_si128();
+
+    //convert blocks of samples with intrinsics
+    size_t i = 0; for (; i < (nsamps & ~0x3); i+=4){
+        //load from input
+        __m128i tmpi = _mm_loadu_si128(reinterpret_cast<const __m128i *>(input+i));
+
+        //unpack + swap 16-bit pairs
+        tmpi = _mm_shufflelo_epi16(tmpi, _MM_SHUFFLE(2, 3, 0, 1));
+        tmpi = _mm_shufflehi_epi16(tmpi, _MM_SHUFFLE(2, 3, 0, 1));
+        __m128i tmpilo = _mm_unpacklo_epi16(zeroi, tmpi); //value in upper 16 bits
+        __m128i tmpihi = _mm_unpackhi_epi16(zeroi, tmpi);
+
+        //convert and scale
+        __m128 tmplo = _mm_mul_ps(_mm_cvtepi32_ps(tmpilo), scalar);
+        __m128 tmphi = _mm_mul_ps(_mm_cvtepi32_ps(tmpihi), scalar);
+
+        //store to output
+        _mm_storeu_ps(reinterpret_cast<float *>(output+i+0), tmplo);
+        _mm_storeu_ps(reinterpret_cast<float *>(output+i+2), tmphi);
+    }
+
+    //convert remainder
+    for (; i < nsamps; i++){
+        output[i] = item32_to_fc32(input[i]);
+    }
+}
+
+#else
 static UHD_INLINE void item32_to_fc32_nswap(
     const item32_t *input, fc32_t *output, size_t nsamps
 ){
@@ -152,10 +231,12 @@ static UHD_INLINE void item32_to_fc32_nswap(
         output[i] = item32_to_fc32(input[i]);
     }
 }
+#endif
 
+////////////////////////////////////
+// byte-swap
+////////////////////////////////////
 #if defined(USE_EMMINTRIN_H)
-#include <emmintrin.h>
-
 static UHD_INLINE void item32_to_fc32_bswap(
     const item32_t *input, fc32_t *output, size_t nsamps
 ){
@@ -167,7 +248,7 @@ static UHD_INLINE void item32_to_fc32_bswap(
         //load from input
         __m128i tmpi = _mm_loadu_si128(reinterpret_cast<const __m128i *>(input+i));
 
-        //byteswap + unpack -> byteswap 32 bit words
+        //byteswap + unpack -> byteswap 16 bit words
         tmpi = _mm_or_si128(_mm_srli_epi16(tmpi, 8), _mm_slli_epi16(tmpi, 8));
         __m128i tmpilo = _mm_unpacklo_epi16(zeroi, tmpi); //value in upper 16 bits
         __m128i tmpihi = _mm_unpackhi_epi16(zeroi, tmpi);
diff --git a/host/lib/usrp/dboard/db_basic_and_lf.cpp b/host/lib/usrp/dboard/db_basic_and_lf.cpp
index f8236d598..0b6e4a75a 100644
--- a/host/lib/usrp/dboard/db_basic_and_lf.cpp
+++ b/host/lib/usrp/dboard/db_basic_and_lf.cpp
@@ -170,8 +170,8 @@ void basic_rx::rx_set(const wax::obj &key_, const wax::obj &val){
         return;
 
     case SUBDEV_PROP_ANTENNA:
-        UHD_ASSERT_THROW(val.as<std::string>() == std::string(""));
-        return;
+        if (val.as<std::string>().empty()) return;
+        throw std::runtime_error("no selectable antennas on this board");
 
     case SUBDEV_PROP_FREQ:
         return; // it wont do you much good, but you can set it
@@ -259,8 +259,8 @@ void basic_tx::tx_set(const wax::obj &key_, const wax::obj &val){
         return;
 
     case SUBDEV_PROP_ANTENNA:
-        UHD_ASSERT_THROW(val.as<std::string>() == std::string(""));
-        return;
+        if (val.as<std::string>().empty()) return;
+        throw std::runtime_error("no selectable antennas on this board");
 
     case SUBDEV_PROP_FREQ:
         return; // it wont do you much good, but you can set it
diff --git a/host/lib/usrp/simple_usrp.cpp b/host/lib/usrp/simple_usrp.cpp
index 60b25a647..e573d0fc0 100644
--- a/host/lib/usrp/simple_usrp.cpp
+++ b/host/lib/usrp/simple_usrp.cpp
@@ -168,6 +168,10 @@ public:
         return _rx_subdev()[SUBDEV_PROP_RSSI].as<float>();
     }
 
+    dboard_iface::sptr get_rx_dboard_iface(void){
+        return _rx_dboard()[DBOARD_PROP_DBOARD_IFACE].as<dboard_iface::sptr>();
+    }
+
     /*******************************************************************
      * TX methods
      ******************************************************************/
@@ -232,6 +236,10 @@ public:
         return _tx_subdev()[SUBDEV_PROP_LO_LOCKED].as<bool>();
     }
 
+    dboard_iface::sptr get_tx_dboard_iface(void){
+        return _tx_dboard()[DBOARD_PROP_DBOARD_IFACE].as<dboard_iface::sptr>();
+    }
+
 private:
     device::sptr _dev;
     wax::obj _mboard(void){
diff --git a/host/lib/usrp/usrp2/dboard_iface.cpp b/host/lib/usrp/usrp2/dboard_iface.cpp
index 8bded1ea3..f6d2b718a 100644
--- a/host/lib/usrp/usrp2/dboard_iface.cpp
+++ b/host/lib/usrp/usrp2/dboard_iface.cpp
@@ -51,6 +51,7 @@ public:
     void set_atr_reg(unit_t, atr_reg_t, boost::uint16_t);
     void set_gpio_ddr(unit_t, boost::uint16_t);
     void write_gpio(unit_t, boost::uint16_t);
+    void set_gpio_debug(unit_t, int);
     boost::uint16_t read_gpio(unit_t);
 
     void write_i2c(boost::uint8_t, const byte_vector_t &);
@@ -219,6 +220,25 @@ void usrp2_dboard_iface::set_atr_reg(unit_t unit, atr_reg_t atr, boost::uint16_t
     _iface->poke16(unit_to_atr_to_addr[unit][atr], value);
 }
 
+void usrp2_dboard_iface::set_gpio_debug(unit_t unit, int which){
+    this->set_gpio_ddr(unit, 0xffff); //all outputs
+
+    //calculate the new selection mux setting
+    boost::uint32_t new_sels = 0x0;
+    int sel = (which == 0)?
+        U2_FLAG_GPIO_SEL_DEBUG_0:
+        U2_FLAG_GPIO_SEL_DEBUG_1;
+    for(size_t i = 0; i < 16; i++){
+        new_sels |= sel << (i*2);
+    }
+
+    //write the selection mux value to register
+    switch(unit){
+    case UNIT_RX: _iface->poke32(U2_REG_GPIO_RX_SEL, new_sels); return;
+    case UNIT_TX: _iface->poke32(U2_REG_GPIO_TX_SEL, new_sels); return;
+    }
+}
+
 /***********************************************************************
  * SPI
  **********************************************************************/
diff --git a/host/test/convert_types_test.cpp b/host/test/convert_types_test.cpp
index 1587be57f..d132a708b 100644
--- a/host/test/convert_types_test.cpp
+++ b/host/test/convert_types_test.cpp
@@ -17,109 +17,144 @@
 
 #include <uhd/transport/convert_types.hpp>
 #include <boost/test/unit_test.hpp>
+#include <boost/foreach.hpp>
 #include <boost/cstdint.hpp>
+#include <boost/asio/buffer.hpp>
 #include <complex>
+#include <vector>
+#include <cstdlib>
 
 using namespace uhd;
 
-template <typename host_type, typename dev_type, size_t nsamps>
-void loopback(
+//typedefs for complex types
+typedef std::complex<boost::uint16_t> sc16_t;
+typedef std::complex<float> fc32_t;
+
+//extract pointer to POD since using &vector.front() throws in MSVC
+template <typename T> void * pod2ptr(T &pod){
+    return boost::asio::buffer_cast<void *>(boost::asio::buffer(pod));
+}
+template <typename T> const void * pod2ptr(const T &pod){
+    return boost::asio::buffer_cast<const void *>(boost::asio::buffer(pod));
+}
+
+/***********************************************************************
+ * Loopback runner:
+ *    convert input buffer into intermediate buffer
+ *    convert intermediate buffer into output buffer
+ **********************************************************************/
+template <typename Range> static void loopback(
+    size_t nsamps,
     const io_type_t &io_type,
     const otw_type_t &otw_type,
-    const host_type *input,
-    host_type *output
+    const Range &input,
+    Range &output
 ){
-    dev_type dev[nsamps];
+    //item32 is largest device type
+    std::vector<boost::uint32_t> dev(nsamps);
 
     //convert to dev type
     transport::convert_io_type_to_otw_type(
-        input, io_type,
-        dev, otw_type,
+        pod2ptr(input), io_type,
+        pod2ptr(dev), otw_type,
         nsamps
     );
 
     //convert back to host type
     transport::convert_otw_type_to_io_type(
-        dev, otw_type,
-        output, io_type,
+        pod2ptr(dev), otw_type,
+        pod2ptr(output), io_type,
         nsamps
     );
 }
 
-typedef std::complex<boost::uint16_t> sc16_t;
+/***********************************************************************
+ * Test short conversion
+ **********************************************************************/
+static void test_convert_types_sc16(
+    size_t nsamps,
+    const io_type_t &io_type,
+    const otw_type_t &otw_type
+){
+    //fill the input samples
+    std::vector<sc16_t> input(nsamps), output(nsamps);
+    BOOST_FOREACH(sc16_t &in, input) in = sc16_t(
+        std::rand()-(RAND_MAX/2),
+        std::rand()-(RAND_MAX/2)
+    );
 
-BOOST_AUTO_TEST_CASE(test_convert_types_be_sc16){
-    sc16_t in_sc16[] = {
-        sc16_t(0, -1234), sc16_t(4321, 1234),
-        sc16_t(9876, -4567), sc16_t(8912, 0)
-    }, out_sc16[4];
+    //run the loopback and test
+    loopback(nsamps, io_type, otw_type, input, output);
+    BOOST_CHECK_EQUAL_COLLECTIONS(input.begin(), input.end(), output.begin(), output.end());
+}
 
+BOOST_AUTO_TEST_CASE(test_convert_types_be_sc16){
     io_type_t io_type(io_type_t::COMPLEX_INT16);
     otw_type_t otw_type;
     otw_type.byteorder = otw_type_t::BO_BIG_ENDIAN;
     otw_type.width = 16;
 
-    loopback<sc16_t, boost::uint32_t, 4>(io_type, otw_type, in_sc16, out_sc16);
-    BOOST_CHECK_EQUAL_COLLECTIONS(in_sc16, in_sc16+4, out_sc16, out_sc16+4);
+    //try various lengths to test edge cases
+    for (size_t nsamps = 0; nsamps < 16; nsamps++){
+        test_convert_types_sc16(nsamps, io_type, otw_type);
+    }
 }
 
 BOOST_AUTO_TEST_CASE(test_convert_types_le_sc16){
-    sc16_t in_sc16[] = {
-        sc16_t(0, -1234), sc16_t(4321, 1234),
-        sc16_t(9876, -4567), sc16_t(8912, 0)
-    }, out_sc16[4];
-
     io_type_t io_type(io_type_t::COMPLEX_INT16);
     otw_type_t otw_type;
     otw_type.byteorder = otw_type_t::BO_LITTLE_ENDIAN;
     otw_type.width = 16;
 
-    loopback<sc16_t, boost::uint32_t, 4>(io_type, otw_type, in_sc16, out_sc16);
-    BOOST_CHECK_EQUAL_COLLECTIONS(in_sc16, in_sc16+4, out_sc16, out_sc16+4);
+    //try various lengths to test edge cases
+    for (size_t nsamps = 0; nsamps < 16; nsamps++){
+        test_convert_types_sc16(nsamps, io_type, otw_type);
+    }
 }
 
-typedef std::complex<float> fc32_t;
-
-#define BOOST_CHECK_CLOSE_COMPLEX(a1, a2, p) \
-    BOOST_CHECK_CLOSE(a1.real(), a2.real(), p); \
-    BOOST_CHECK_CLOSE(a1.imag(), a2.imag(), p);
+/***********************************************************************
+ * Test float conversion
+ **********************************************************************/
+static void test_convert_types_fc32(
+    size_t nsamps,
+    const io_type_t &io_type,
+    const otw_type_t &otw_type
+){
+    //fill the input samples
+    std::vector<fc32_t> input(nsamps), output(nsamps);
+    BOOST_FOREACH(fc32_t &in, input) in = fc32_t(
+        (std::rand()/float(RAND_MAX/2)) - 1,
+        (std::rand()/float(RAND_MAX/2)) - 1
+    );
 
-static const float tolerance = float(0.1);
+    //run the loopback and test
+    loopback(nsamps, io_type, otw_type, input, output);
+    for (size_t i = 0; i < nsamps; i++){
+        BOOST_CHECK_CLOSE_FRACTION(input[i].real(), output[i].real(), float(0.01));
+        BOOST_CHECK_CLOSE_FRACTION(input[i].imag(), output[i].imag(), float(0.01));
+    }
+}
 
 BOOST_AUTO_TEST_CASE(test_convert_types_be_fc32){
-    fc32_t in_fc32[] = {
-        fc32_t(float(0), float(-0.2)), fc32_t(float(0.03), float(-0.16)),
-        fc32_t(float(1.0), float(.45)), fc32_t(float(0.09), float(0))
-    }, out_fc32[4];
-
     io_type_t io_type(io_type_t::COMPLEX_FLOAT32);
     otw_type_t otw_type;
     otw_type.byteorder = otw_type_t::BO_BIG_ENDIAN;
     otw_type.width = 16;
 
-    loopback<fc32_t, boost::uint32_t, 4>(io_type, otw_type, in_fc32, out_fc32);
-
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[0], out_fc32[0], tolerance);
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[1], out_fc32[1], tolerance);
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[2], out_fc32[2], tolerance);
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[3], out_fc32[3], tolerance);
+    //try various lengths to test edge cases
+    for (size_t nsamps = 0; nsamps < 16; nsamps++){
+        test_convert_types_fc32(nsamps, io_type, otw_type);
+    }
 }
 
 BOOST_AUTO_TEST_CASE(test_convert_types_le_fc32){
-    fc32_t in_fc32[] = {
-        fc32_t(float(0), float(-0.2)), fc32_t(float(0.03), float(-0.16)),
-        fc32_t(float(1.0), float(.45)), fc32_t(float(0.09), float(0))
-    }, out_fc32[4];
-
     io_type_t io_type(io_type_t::COMPLEX_FLOAT32);
     otw_type_t otw_type;
     otw_type.byteorder = otw_type_t::BO_LITTLE_ENDIAN;
     otw_type.width = 16;
 
-    loopback<fc32_t, boost::uint32_t, 4>(io_type, otw_type, in_fc32, out_fc32);
-
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[0], out_fc32[0], tolerance);
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[1], out_fc32[1], tolerance);
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[2], out_fc32[2], tolerance);
-    BOOST_CHECK_CLOSE_COMPLEX(in_fc32[3], out_fc32[3], tolerance);
+    //try various lengths to test edge cases
+    for (size_t nsamps = 0; nsamps < 16; nsamps++){
+        test_convert_types_fc32(nsamps, io_type, otw_type);
+    }
 }