From 46b01cbf6e375eee7291efe7a4842a928bde4440 Mon Sep 17 00:00:00 2001
From: "Pavel V. Shatov (Meister)" <meisterpaul1@yandex.ru>
Date: Tue, 27 Jun 2017 13:42:16 +0300
Subject: Added generic processing elements.

---
 src/rtl/pe/modexpa7_pe_sub.v | 63 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 src/rtl/pe/modexpa7_pe_sub.v

(limited to 'src/rtl/pe/modexpa7_pe_sub.v')

diff --git a/src/rtl/pe/modexpa7_pe_sub.v b/src/rtl/pe/modexpa7_pe_sub.v
new file mode 100644
index 0000000..85c5f65
--- /dev/null
+++ b/src/rtl/pe/modexpa7_pe_sub.v
@@ -0,0 +1,63 @@
+//======================================================================
+//
+// modexpa7_pe_sub.v
+// -----------------------------------------------------------------------------
+// Low-level processing element (subtractor).
+//
+// Authors: Pavel Shatov
+//
+// Copyright (c) 2017, 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 modexpa7_pe_sub
+	(
+		input					clk,
+		input					ce,
+		input		[31: 0]	a,
+		input		[31: 0]	b,
+		input					b_in,
+		output	[31: 0]	d,
+		output				b_out
+	);
+	
+	reg	[32: 0]	d_reg;
+	
+	assign d			= d_reg[31: 0];
+	assign b_out	= d_reg[32];
+	
+	always @(posedge clk)
+		//
+		if (ce) d_reg <= {1'b0, a} - {1'b0, b} - {32'd0, b_in};
+
+endmodule
+
+//======================================================================
+// End of file
+//======================================================================
-- 
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