1 files changed, 43 insertions, 0 deletions
diff --git a/fpga/usrp2/sdr_lib/clip_and_round.v b/fpga/usrp2/sdr_lib/clip_and_round.v
new file mode 100644
index 000000000..4546283a3
--- /dev/null
+++ b/fpga/usrp2/sdr_lib/clip_and_round.v
@@ -0,0 +1,43 @@
+// -*- verilog -*-
+//
+//  USRP - Universal Software Radio Peripheral
+//
+//  Copyright (C) 2008 Matt Ettus
+//
+//  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 2 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, write to the Free Software
+//  Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA
+//
+
+// Clipping "macro", keeps the bottom bits
+
+module clip_and_round
+  #(parameter bits_in=0,
+    parameter bits_out=0,
+    parameter clip_bits=0)
+    (input [bits_in-1:0] in,
+     output [bits_out-1:0] out);
+
+   wire [bits_out-1:0] 	   rounded;
+   
+   round #(.bits_in(bits_in-clip_bits),.bits_out(bits_out))
+     round (.in(in[bits_in-clip_bits-1:0]),.out(rounded));
+   
+   wire 		   overflow = |in[bits_in-1:bits_in-clip_bits-1] 
+			   & ~(&in[bits_in-1:bits_in-clip_bits-1]);
+   
+   assign 		   out = overflow ? 
+			   (in[bits_in-1] ? {1'b1,{(bits_out-1){1'b0}}} : {1'b0,{(bits_out-1){1'b1}}}) :
+			   rounded;
+   
+endmodule // clip_and_round