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// http://www.gnu.org/licenses/gpl.html
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// http://www.gnu.org/licenses/gpl.html
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//
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//
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//
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//
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///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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//
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//
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// `define LONG_MPY
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`define LONG_MPY
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module cpuops(i_clk,i_rst, i_ce, i_valid, i_op, i_a, i_b, o_c, o_f, o_valid,
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module cpuops(i_clk,i_rst, i_ce, i_valid, i_op, i_a, i_b, o_c, o_f, o_valid,
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o_illegal, o_busy);
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o_illegal, o_busy);
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parameter IMPLEMENT_MPY = 1;
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parameter IMPLEMENT_MPY = 1;
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input i_clk, i_rst, i_ce;
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input i_clk, i_rst, i_ce;
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input [3:0] i_op;
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input [3:0] i_op;
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Line 238... |
// = 2^32(ah*bh)
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// = 2^32(ah*bh)
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// +2^16 (ah*bl+al*bh)
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// +2^16 (ah*bl+al*bh)
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// +(al*bl)
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// +(al*bl)
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// - 2^31 (2^16 bh+bl + 2^16 ah+al + 2^31)
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// - 2^31 (2^16 bh+bl + 2^16 ah+al + 2^31)
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//
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//
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reg [31:0] pp_f, pp_o, pp_i, pp_l;
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reg [31:0] pp_f, pp_l; // F and L from FOIL
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reg [32:0] pp_oi; // The O and I from FOIL
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reg [32:0] pp_s;
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reg [32:0] pp_s;
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always @(posedge i_clk)
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always @(posedge i_clk)
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begin
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begin
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pp_f<=r_mpy_a_input[31:16]*r_mpy_b_input[31:16];
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pp_f<=r_mpy_a_input[31:16]*r_mpy_b_input[31:16];
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pp_o<=r_mpy_a_input[31:16]*r_mpy_b_input[15: 0];
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pp_oi<=r_mpy_a_input[31:16]*r_mpy_b_input[15: 0]
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pp_i<=r_mpy_a_input[15: 0]*r_mpy_b_input[31:16];
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+ r_mpy_a_input[15: 0]*r_mpy_b_input[31:16];
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pp_l<=r_mpy_a_input[15: 0]*r_mpy_b_input[15: 0];
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pp_l<=r_mpy_a_input[15: 0]*r_mpy_b_input[15: 0];
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// And a special one for the sign
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// And a special one for the sign
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if (r_mpy_signed)
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if (r_mpy_signed)
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pp_s <= 32'h8000_0000-(
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pp_s <= 32'h8000_0000-(
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r_mpy_a_input[31:0]
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r_mpy_a_input[31:0]
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always @(posedge i_clk)
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always @(posedge i_clk)
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begin
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begin
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r_mpy_result[15:0] <= pp_l[15:0];
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r_mpy_result[15:0] <= pp_l[15:0];
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r_mpy_result[63:16] <=
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r_mpy_result[63:16] <=
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{ 32'h00, pp_l[31:16] }
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{ 32'h00, pp_l[31:16] }
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+ { 16'h00, pp_o }
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+ { 15'h00, pp_oi }
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+ { 16'h00, pp_i }
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+ { pp_s, 15'h00 }
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+ { pp_s, 15'h00 }
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+ { pp_f, 16'h00 };
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+ { pp_f, 16'h00 };
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end
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end
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end // Fourth clock -- results are available for writeback.
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end // Fourth clock -- results are available for writeback.
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`else
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`else
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