Added README.md with core description, API details, etc

Added previously forgotten generic replacements for vendor-specific primitives
Minor clean up of comments
Slightly reduced power consumption

6 files changed, 274 insertions, 2 deletions

diff --git a/rtl/lowlevel/artix7/dsp48e1_wrapper.v b/rtl/lowlevel/artix7/dsp48e1_wrapper.v
index 9f29ac1..11a21bc 100644
--- a/rtl/lowlevel/artix7/dsp48e1_wrapper.v
+++ b/rtl/lowlevel/artix7/dsp48e1_wrapper.v
@@ -63,7 +63,7 @@ module dsp48e1_wrapper
 		.AREG						(0),
 		.BREG						(0),
 		.CREG						(0),
-		.DREG						(1),
+		.DREG						(0),
 		.MREG						(0),
 		.PREG						(1),
 		.ADREG					(0),

diff --git a/rtl/lowlevel/artix7/mac16_artix7.v b/rtl/lowlevel/artix7/mac16_artix7.v
index 09a2413..63b74ab 100644
--- a/rtl/lowlevel/artix7/mac16_artix7.v
+++ b/rtl/lowlevel/artix7/mac16_artix7.v
@@ -2,7 +2,7 @@
 //
 // mac16_artix7.v
 // -----------------------------------------------------------------------------
-// Hardware (Artix-7 DSP48E1) 16-bit multiplier and 48-bit accumulator.

+// Hardware (Artix-7 DSP48E1) 16-bit multiplier and 47-bit accumulator.

 //
 // Authors: Pavel Shatov
 //
diff --git a/rtl/lowlevel/generic/adder32_generic.v b/rtl/lowlevel/generic/adder32_generic.v
new file mode 100644
index 0000000..b9c94aa
--- /dev/null
+++ b/rtl/lowlevel/generic/adder32_generic.v
@@ -0,0 +1,67 @@
+//------------------------------------------------------------------------------
+//
+// adder32_generic.v
+// -----------------------------------------------------------------------------
+// Generic 32-bit adder.

+//
+// Authors: Pavel Shatov
+//
+// Copyright (c) 2016, NORDUnet A/S
+//
+// 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 adder32_generic

+	(

+		input					clk,		// clock

+		input		[31: 0]	a,			// operand input

+		input		[31: 0]	b,			// operand input

+		output	[31: 0]	s,			// sum output

+		input					c_in,		// carry input

+		output				c_out		// carry output

+	);

+	
+		//
+		// Sum
+		//
+	reg	[32: 0]	s_int;

+	

+	always @(posedge clk)

+		s_int <= {1'b0, a} + {1'b0, b} + {{32{1'b0}}, c_in};

+		

+		//

+		// Output

+		//

+	assign s = s_int[31:0];

+	assign c_out = s_int[32];

+		

+endmodule

+

+//------------------------------------------------------------------------------
+// End-of-File
+//------------------------------------------------------------------------------

diff --git a/rtl/lowlevel/generic/adder47_generic.v b/rtl/lowlevel/generic/adder47_generic.v
new file mode 100644
index 0000000..f472061
--- /dev/null
+++ b/rtl/lowlevel/generic/adder47_generic.v
@@ -0,0 +1,64 @@
+//------------------------------------------------------------------------------
+//
+// adder47_generic.v
+// -----------------------------------------------------------------------------
+// Generic 47-bit adder.

+//
+// Authors: Pavel Shatov
+//
+// Copyright (c) 2016, NORDUnet A/S
+//
+// 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 adder47_generic

+	(

+		input					clk,		// clock

+		input		[46: 0]	a,			// operand input

+		input		[46: 0]	b,			// operand input

+		output	[46: 0]	s			// sum output

+	);

+	

+		//
+		// Sum
+		//
+	reg	[46: 0]	s_int;

+	

+	always @(posedge clk)

+		s_int <= a + b;

+		

+		//

+		// Output

+		//

+	assign s = s_int;

+

+endmodule

+

+//------------------------------------------------------------------------------
+// End-of-File
+//------------------------------------------------------------------------------

diff --git a/rtl/lowlevel/generic/mac16_generic.v b/rtl/lowlevel/generic/mac16_generic.v
new file mode 100644
index 0000000..dc95645
--- /dev/null
+++ b/rtl/lowlevel/generic/mac16_generic.v
@@ -0,0 +1,74 @@
+//------------------------------------------------------------------------------
+//
+// mac16_generic.v
+// -----------------------------------------------------------------------------
+// Generic 16-bit multiplier and 47-bit accumulator.

+//
+// Authors: Pavel Shatov
+//
+// Copyright (c) 2016, NORDUnet A/S
+//
+// 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 mac16_generic

+	(

+		input					clk,		// clock

+		input					clr,		// clear accumulator (active-high)

+		input					ce,		// enable clock (active-high)

+		input		[15: 0]	a,			// operand input

+		input		[15: 0]	b,			// operand input

+		output	[46: 0]	s			// sum output

+	);

+	

+		//

+		// Multiplier

+		//

+	wire	[31: 0]	p = {{16{1'b0}}, a} * {{16{1'b0}}, b};

+	wire	[46: 0]	p_ext = {{15{1'b0}}, p};

+		

+		//

+		// Accumulator

+		//

+	reg	[46: 0]	s_int;

+	

+	always @(posedge clk)

+		//

+		if (ce) s_int <= clr ? p_ext : p_ext + s_int;

+		

+		//

+		// Output

+		//

+	assign s = s_int;

+

+endmodule

+

+

+//------------------------------------------------------------------------------
+// End-of-File
+//------------------------------------------------------------------------------

diff --git a/rtl/lowlevel/generic/subtractor32_generic.v b/rtl/lowlevel/generic/subtractor32_generic.v
new file mode 100644
index 0000000..46aefe8
--- /dev/null
+++ b/rtl/lowlevel/generic/subtractor32_generic.v
@@ -0,0 +1,67 @@
+//------------------------------------------------------------------------------

+//

+// subtractor32_generic.v

+// -----------------------------------------------------------------------------

+// Generic 32-bit subtractor.

+//

+// Authors: Pavel Shatov

+//

+// Copyright (c) 2016, NORDUnet A/S

+//

+// 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 subtractor32_generic

+	(

+		input					clk,

+		input		[31: 0]	a,

+		input		[31: 0]	b,

+		output	[31: 0]	d,

+		input					b_in,

+		output				b_out	

+	);

+

+		//
+		// Difference
+		//
+	reg	[32: 0]	d_int;

+	

+	always @(posedge clk)

+		d_int <= {1'b0, a} - {1'b0, b} - {{32{1'b0}}, b_in};

+		

+		//

+		// Output

+		//

+	assign d = d_int[31:0];

+	assign b_out = d_int[32];

+

+endmodule

+

+//------------------------------------------------------------------------------

+// End-of-File

+//------------------------------------------------------------------------------