core: reverting float_to_int to non-Volk due to precision/wrapping issues.

Using the Volk function causes too much of a change in the output values right now. Will have to relook at it for the right thing to do. Keeping the use of vlen and scale, though.

3 files changed, 17 insertions, 7 deletions

diff --git a/gnuradio-core/src/lib/general/gr_float_to_int.cc b/gnuradio-core/src/lib/general/gr_float_to_int.cc
index 28214538f..b69591043 100644
--- a/gnuradio-core/src/lib/general/gr_float_to_int.cc
+++ b/gnuradio-core/src/lib/general/gr_float_to_int.cc
@@ -26,6 +26,7 @@
 
 #include <gr_float_to_int.h>
 #include <gr_io_signature.h>
+#include <gri_float_to_int.h>
 #include <volk/volk.h>
 
 gr_float_to_int_sptr
@@ -56,12 +57,17 @@ gr_float_to_int::set_scale(float scale)
 {
   d_scale = scale;
 }
-
 int
 gr_float_to_int::work (int noutput_items,
 		       gr_vector_const_void_star &input_items,
 		       gr_vector_void_star &output_items)
 {
+  // Disable the Volk for now. There is a problem for large 32-bit ints that
+  // are not properly represented by the precisions of a single float, which
+  // can cause wrapping from large, positive numbers to negative.
+  // In gri_float_to_int, the value is first promoted to a 64-bit
+  // value, clipped, then converted to a float.
+#if 0
   const float *in = (const float *) input_items[0];
   int32_t *out = (int32_t *) output_items[0];
 
@@ -71,9 +77,13 @@ gr_float_to_int::work (int noutput_items,
   else {
     volk_32f_s32f_convert_32i_a(out, in, d_scale, d_vlen*noutput_items);
   }
+#else
+  const float *in = (const float *) input_items[0];
+  int *out = (int *) output_items[0];
+
+  gri_float_to_int (in, out, d_scale, d_vlen*noutput_items);
+
+#endif
   
   return noutput_items;
 }
-
-
-
diff --git a/gnuradio-core/src/lib/general/gri_float_to_int.cc b/gnuradio-core/src/lib/general/gri_float_to_int.cc
index 5271e60e2..0b0b10dfe 100644
--- a/gnuradio-core/src/lib/general/gri_float_to_int.cc
+++ b/gnuradio-core/src/lib/general/gri_float_to_int.cc
@@ -34,10 +34,10 @@ static const int64_t MIN_INT = -2147483647; // -(2^31)-1
 
 
 void 
-gri_float_to_int (const float *in, int *out, int nsamples)
+gri_float_to_int (const float *in, int *out, float scale, int nsamples)
 {
   for (int i = 0; i < nsamples; i++){
-    int64_t r = llrintf(in[i]);
+    int64_t r = llrintf(scale * in[i]);
     if (r < MIN_INT)
       r = MIN_INT;
     else if (r > MAX_INT)
diff --git a/gnuradio-core/src/lib/general/gri_float_to_int.h b/gnuradio-core/src/lib/general/gri_float_to_int.h
index a2f6ea877..d8b98efc1 100644
--- a/gnuradio-core/src/lib/general/gri_float_to_int.h
+++ b/gnuradio-core/src/lib/general/gri_float_to_int.h
@@ -28,6 +28,6 @@
 /*!
  * convert array of floats to int with rounding and saturation.
  */
-GR_CORE_API void gri_float_to_int (const float *in, int *out, int nsamples);
+GR_CORE_API void gri_float_to_int (const float *in, int *out, float scale, int nsamples);
 
 #endif /* INCLUDED_GRI_FLOAT_TO_INT_H */