diff options
| author | Pavel V. Shatov (Meister) <meisterpaul1@yandex.ru> | 2017-06-13 20:11:58 +0300 |
|---|---|---|
| committer | Pavel V. Shatov (Meister) <meisterpaul1@yandex.ru> | 2017-06-13 20:11:58 +0300 |
| commit | 53e92c5355aca120eab8d59e6904282c9e3b4ab1 (patch) | |
| tree | 62c6b65e52c01bbbfdac063ec8ba791a9d073203 /modexp_fpga_model_pe.cpp | |
Initial commit of faster modular exponentiation model based on systolic architecture.
Diffstat (limited to 'modexp_fpga_model_pe.cpp')
| -rw-r--r-- | modexp_fpga_model_pe.cpp | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/modexp_fpga_model_pe.cpp b/modexp_fpga_model_pe.cpp new file mode 100644 index 0000000..4f58bee --- /dev/null +++ b/modexp_fpga_model_pe.cpp @@ -0,0 +1,119 @@ +//
+// modexp_fpga_model_pe.cpp
+// -----------------------------
+// Low-level processing elements
+//
+// 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.
+//
+
+
+//----------------------------------------------------------------
+// Headers
+//----------------------------------------------------------------
+#include "modexp_fpga_model.h"
+#include "modexp_fpga_model_pe.h"
+
+
+//----------------------------------------------------------------
+// Low-level 32-bit multiplier with pre-adder
+//----------------------------------------------------------------
+void pe_mul( FPGA_WORD a, FPGA_WORD b,
+ FPGA_WORD t, FPGA_WORD c_in,
+ FPGA_WORD *p, FPGA_WORD *c_out)
+//----------------------------------------------------------------
+//
+// {c_out, p} = a * b + t + c_in
+//
+// Note, that the output will never overflow, because 0xFFFFFFFF^2 +
+// 2*0xFFFFFFFF is exactly 0xFFFFFFFFFFFFFFFF. Doh, we're lucky...
+//
+//----------------------------------------------------------------
+{
+ _WIDE_WORD s = (_WIDE_WORD)a * (_WIDE_WORD)b; // get product from multiplier
+
+ s += (_WIDE_WORD)t; // trigger pre-adder
+ s += (_WIDE_WORD)c_in; // take carry into account
+
+ *p = (FPGA_WORD)s; // return the lower part of result
+ *c_out = (FPGA_WORD)(s >> (CHAR_BIT * sizeof(FPGA_WORD))); // return the higher part of result
+}
+
+
+//----------------------------------------------------------------
+// Low-level 32-bit adder
+//----------------------------------------------------------------
+void pe_add( FPGA_WORD a,
+ FPGA_WORD b,
+ FPGA_WORD c_in,
+ FPGA_WORD *s,
+ FPGA_WORD *c_out)
+//----------------------------------------------------------------
+//
+// {c_out, s} = a + b + c_in
+//
+//----------------------------------------------------------------
+{
+ _WIDE_WORD t = (_WIDE_WORD)a + (_WIDE_WORD)b; // get sum from adder
+
+ t += (_WIDE_WORD)(c_in & 1); // take carry into account
+
+ *s = (FPGA_WORD)t; // return the lower part of resukt
+ *c_out = (FPGA_WORD)(t >> (CHAR_BIT * sizeof(FPGA_WORD))) & 1; // return the higher part of result
+
+}
+
+
+//----------------------------------------------------------------
+// Low-level 32-bit subtractor
+//----------------------------------------------------------------
+void pe_sub( FPGA_WORD a,
+ FPGA_WORD b,
+ FPGA_WORD b_in,
+ FPGA_WORD *d,
+ FPGA_WORD *b_out)
+//----------------------------------------------------------------
+//
+// {b_out, d} = a - b - b_in
+//
+//----------------------------------------------------------------
+{
+ _WIDE_WORD t = (_WIDE_WORD)a - (_WIDE_WORD)b; // get difference from subtractor
+
+ t -= (_WIDE_WORD)(b_in & 1); // take borrow into account
+
+ *d = (FPGA_WORD)t; // return the lower part of result
+ *b_out = (FPGA_WORD)(t >> (CHAR_BIT * sizeof(FPGA_WORD))) & 1; // return the higher part of result
+}
+
+
+//----------------------------------------------------------------
+// End of file
+//----------------------------------------------------------------
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