From abef23206f8882ba00dddf3293c250c4601fd920 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joachim=20Stro=CC=88mbergson?= <joachim@secworks.se>
Date: Mon, 13 Apr 2015 14:22:09 +0200
Subject: Adding initial versions of rtl for modexp. Montgomery multiplication
 works for 8192 bit operands. Modexp can build, but lacks proper control and
 residue generator. Memories has been tested to match block memories in Xilinx
 and Altera FPGAs.

---
 src/rtl/blockmem1r1w.v | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/rtl/blockmem1r1w.v

(limited to 'src/rtl/blockmem1r1w.v')

diff --git a/src/rtl/blockmem1r1w.v b/src/rtl/blockmem1r1w.v
new file mode 100644
index 0000000..1d84369
--- /dev/null
+++ b/src/rtl/blockmem1r1w.v
@@ -0,0 +1,70 @@
+//======================================================================
+//
+// blockmem1rw1.v
+// --------------
+// Synchronous block memory with one read and one write port.
+// The data size is the same for both read and write operations.
+//
+// The memory is used in the modexp core.
+//
+//
+// Author: Joachim Strombergson
+// Copyright (c) 2015, NORDUnet A/S All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// - Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+//
+// - Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in the
+//   documentation and/or other materials provided with the distribution.
+//
+// - Neither the name of the NORDUnet nor the names of its contributors may
+//   be used to endorse or promote products derived from this software
+//   without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+//======================================================================
+
+module blockmem1r1w(
+                    input wire           clk,
+
+                    input wire  [07 : 0] read_addr,
+                    output wire [31 : 0] read_data,
+
+                    input wire           wr,
+                    input wire  [07 : 0] write_addr,
+                    input wire  [31 : 0] write_data
+                   );
+
+  reg [31 : 0] mem [0 : 255];
+  reg [31 : 0] tmp_read_data;
+
+  assign read_data = tmp_read_data;
+
+  always @ (posedge clk)
+    begin : reg_mem
+      if (wr)
+        mem[write_addr] <= write_data;
+
+      tmp_read_data <= mem[read_addr];
+    end
+
+endmodule // blockmem1r1w
+
+//======================================================================
+// EOF blockmem1r1w.v
+//======================================================================
-- 
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