cores: Fix rx_vita_core_3000 assertion error in issue_stream_cmd()

The current code had an assertion

    UHD_ASSERT_THROW(stream_cmd.num_samps <= 0x0fffffff);

which would check that num_samps in a stream command don't exceed the
counter depth in the FPGA. However, this is only relevant if the stream
command is not "continuous" or "stop".
num_samps could be unitialized, and randomly have a value larger than
the maximum, and the assertion could trigger even though the value in
num_samps is irrelevant.

The new assertion checks for the correct case, and has a more verbose
error message.

1 files changed, 7 insertions, 3 deletions

diff --git a/host/lib/usrp/cores/rx_vita_core_3000.cpp b/host/lib/usrp/cores/rx_vita_core_3000.cpp
index 8a20e637b..4b09f75fd 100644
--- a/host/lib/usrp/cores/rx_vita_core_3000.cpp
+++ b/host/lib/usrp/cores/rx_vita_core_3000.cpp
@@ -82,9 +82,13 @@ struct rx_vita_core_3000_impl : rx_vita_core_3000
             // not setup yet!";
             return;
         }
-        UHD_ASSERT_THROW(stream_cmd.num_samps <= 0x0fffffff);
-        _continuous_streaming = stream_cmd.stream_mode
-                                == stream_cmd_t::STREAM_MODE_START_CONTINUOUS;
+        if ((stream_cmd.stream_mode == stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE
+                || stream_cmd.stream_mode == stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_MORE)
+            && stream_cmd.num_samps > 0x0fffffff) {
+            throw uhd::assertion_error(
+                "Invalid stream command: num_samps exceeds maximum value! "
+                "(Note: Chain multiple commands to request larger bursts)");
+        }
 
         // setup the mode to instruction flags
         typedef std::tuple<bool, bool, bool, bool> inst_t;