Subversion Repositories tiny_tate_bilinear_pairing

/*

 * Copyright 2012, Homer Hsing <homer.hsing@gmail.com>

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 * http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

`define M     503         // M is the degree of the irreducible polynomial

`define WIDTH (2*`M-1)    // width for a GF(3^M) element

`define WIDTH_D0 (1008-1)

/* PE: processing element */

module PE(clk, reset, ctrl, d0, d1, d2, out);

    input clk;

    input reset;

    input [10:0] ctrl;

    input [`WIDTH_D0:0] d0;

    input [`WIDTH:0] d1, d2;

    output [`WIDTH:0] out;

    reg [`WIDTH_D0:0] R0;

    reg [`WIDTH:0] R1, R2, R3;

    wire [1:0] e0, e1, e2; /* part of R0 */

    wire [`WIDTH:0] ppg0, ppg1, ppg2, /* output of PPG */

                    mx0, mx1, mx2, mx3, mx4, mx5, mx6, mx7, /* output of MUX */

                    ad0, ad1, ad2, /* output of GF(3^m) adder */

                    cu0, cu1, cu2, cu3, /* output of cubic */

                    mo0, mo1, mo2, /* output of mod_p */

                    t0, t1, t2;

    wire c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10;

    assign {c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10} = ctrl;

    assign mx0 = c0 ? d1 : ad2;

    assign mx1 = c2 ? d2 : ad2;

    always @ (posedge clk)

        if(reset) R1 <= 0;

        else if (c1) R1 <= mx0;

    always @ (posedge clk)

        if(reset) R2 <= 0;

        else if (c3) R2 <= mx1;

    always @ (posedge clk)

        if(reset) R0 <= 0;

        else if (c4) R0 <= d0;

        else if (c5) R0 <= R0 << 6;

    assign {e2,e1,e0} = R0[`WIDTH_D0:(`WIDTH_D0-5)];

    PPG

        ppg_0 (e0, R1, ppg0),

        ppg_1 (e1, R2, ppg1),

        ppg_2 (e2, R1, ppg2);

    v0  v0_ (ppg0, cu0);

    v1  v1_ (ppg1, cu1);

    v2  v2_ (ppg2, cu2);

    v3  v3_ (R2,   cu3);

    assign mx2 = c6 ? ppg0 : cu0;

    assign mx3 = c6 ? ppg1 : cu1;

    assign mx4 = c6 ? mo1 : cu2;

    assign mx5 = c7 ? mo2 : R3;

    mod_p

        mod_p_0 (mx3, mo0),

        mod_p_1 (ppg2, t0),

        mod_p_2 (t0, mo1),

        mod_p_3 (R3, t1),

        mod_p_4 (t1, t2),

        mod_p_5 (t2, mo2);

    assign mx6 = c9 ? mo0 : mx3;

    assign mx7 = c6 ? (c8 ? mx5 : 0) : cu3;

    f3m_add

        f3m_add_0 (mx2, mx6, ad0),

        f3m_add_1 (mx4, mx7, ad1),

        f3m_add_2 (ad0, ad1, ad2);

    always @ (posedge clk)

        if (reset) R3 <= 0;

        else if (c10) R3 <= ad2;

        else R3 <= 0; /* change */

    assign out = R3;

endmodule

// C = (x*B mod p(x))

module mod_p(B, C);

    input [`WIDTH:0] B;

    output [`WIDTH:0] C;

    wire [`WIDTH+2:0] A;

    assign A = {B[`WIDTH:0], 2'd0}; // A == B*x

    wire [1:0] w0;

    f3_mult m0 (A[1007:1006], 2'd2, w0);

    f3_sub s0 (A[1:0], w0, C[1:0]);

    assign C[207:2] = A[207:2];

    wire [1:0] w104;

    f3_mult m104 (A[1007:1006], 2'd1, w104);

    f3_sub s104 (A[209:208], w104, C[209:208]);

    assign C[1005:210] = A[1005:210];

endmodule

// PPG: partial product generator, C == A*d in GF(3^m)

module PPG(d, A, C);

    input [1:0] d;

    input [`WIDTH:0] A;

    output [`WIDTH:0] C;

    genvar i;

    generate

        for (i=0; i < `M; i=i+1)

        begin: ppg0

            f3_mult f3_mult_0 (d, A[2*i+1:2*i], C[2*i+1:2*i]);

        end

    endgenerate

endmodule

// f3m_add: C = A + B, in field F_{3^M}

module f3m_add(A, B, C);

    input [`WIDTH : 0] A, B;

    output [`WIDTH : 0] C;

    genvar i;

    generate

        for(i=0; i<`M; i=i+1) begin: aa

            f3_add aa(A[(2*i+1) : 2*i], B[(2*i+1) : 2*i], C[(2*i+1) : 2*i]);

        end

    endgenerate

endmodule

// f3_add: C == A+B (mod 3)

module f3_add(A, B, C);

    input [1:0] A, B;

    output [1:0] C;

    wire a0, a1, b0, b1, c0, c1;

    assign {a1, a0} = A;

    assign {b1, b0} = B;

    assign C = {c1, c0};

    assign c0 = ( a0 & ~a1 & ~b0 & ~b1) |

                (~a0 & ~a1 &  b0 & ~b1) |

                (~a0 &  a1 & ~b0 &  b1) ;

    assign c1 = (~a0 &  a1 & ~b0 & ~b1) |

                ( a0 & ~a1 &  b0 & ~b1) |

                (~a0 & ~a1 & ~b0 &  b1) ;

endmodule

// f3_sub: C == A-B (mod 3)

module f3_sub(A, B, C);

    input [1:0] A, B;

    output [1:0] C;

    f3_add a0(A, {B[0],B[1]}, C);

endmodule

// f3_mult: C = A*B (mod 3)

module f3_mult(A, B, C);

    input [1:0] A;

    input [1:0] B;

    output [1:0] C;

    wire a0, a1, b0, b1;

    assign {a1, a0} = A;

    assign {b1, b0} = B;

    assign C[0] = (~a1 & a0 & ~b1 & b0) | (a1 & ~a0 & b1 & ~b0);

    assign C[1] = (~a1 & a0 & b1 & ~b0) | (a1 & ~a0 & ~b1 & b0);

endmodule