// SPDX-License-Identifier: Apache-2.0
// Copyright 2019 Western Digital Corporation or its affiliates.
// 
// 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.

// all flops call the rvdff flop


module rvdff #( parameter WIDTH=1 )
   ( 
     input logic [WIDTH-1:0] din,
     input logic    	   clk,
     input logic	           rst_l,

     output logic [WIDTH-1:0] dout
     );

`ifdef CLOCKGATE
   always @(posedge tb_top.clk) begin
      #0 $strobe("CG: %0t %m din %x dout %x clk %b width %d",$time,din,dout,clk,WIDTH);
   end
`endif

   always_ff @(posedge clk or negedge rst_l) begin
      if (rst_l == 0)
	dout[WIDTH-1:0] <= 0;
      else
	dout[WIDTH-1:0] <= din[WIDTH-1:0];
   end
   
   
endmodule 

// rvdff with 2:1 input mux to flop din iff sel==1
module rvdffs #( parameter WIDTH=1 )
   ( 
     input logic [WIDTH-1:0] din,
     input logic             en,
     input logic    	   clk,
     input logic	           rst_l,
     output logic [WIDTH-1:0] dout
     );
   
   rvdff #(WIDTH) dffs (.din((en) ? din[WIDTH-1:0] : dout[WIDTH-1:0]), .*);
   
endmodule 

// rvdff with en and clear
module rvdffsc #( parameter WIDTH=1 )
   ( 
     input logic [WIDTH-1:0] din,
     input logic             en,
     input logic             clear,
     input logic    	   clk,
     input logic	           rst_l,
     output logic [WIDTH-1:0] dout
     );

   logic [WIDTH-1:0] 	      din_new;
   assign din_new = {WIDTH{~clear}} & (en ? din[WIDTH-1:0] : dout[WIDTH-1:0]);
   rvdff #(WIDTH) dffsc (.din(din_new[WIDTH-1:0]), .*);

endmodule 

module `TEC_RV_ICG
  (
   input logic TE, E, CP,
   output Q 
   );

   logic  en_ff;
   logic  enable;
   
   assign      enable = E | TE;

`ifdef VERILATOR
   always @(negedge CP) begin
      en_ff <= enable;
   end
`else   
   always @(CP, enable) begin
      if(!CP)
        en_ff = enable;
   end
`endif
   assign Q = CP & en_ff;

endmodule

module rvclkhdr
  (
   input  logic en,
   input  logic clk,
   input  logic scan_mode,
   output logic l1clk
   );

   logic 	TE;
   assign       TE = scan_mode;
   
   `TEC_RV_ICG rvclkhdr ( .*, .E(en), .CP(clk), .Q(l1clk));

endmodule

module rvoclkhdr
  (
   input  logic en,
   input  logic clk,
   input  logic scan_mode,
   output logic l1clk
   );

   logic 	TE;
   assign       TE = scan_mode;

`ifdef RV_FPGA_OPTIMIZE
   assign l1clk = clk;
`else
   `TEC_RV_ICG rvclkhdr ( .*, .E(en), .CP(clk), .Q(l1clk));
`endif

endmodule

module rvdffe #( parameter WIDTH=1 )
   ( 
     input  logic [WIDTH-1:0] din,
     input  logic 	    en,
     input  logic 	    clk, 
     input  logic 	    rst_l,
     input  logic             scan_mode,
     output logic [WIDTH-1:0] dout
     );

   logic 		      l1clk;

`ifdef RV_FPGA_OPTIMIZE
   begin: genblock
     rvdffs #(WIDTH) dff ( .* );
   end
`else
   
`ifndef PHYSICAL   
   if (WIDTH >= 8) begin: genblock
`endif
      rvclkhdr clkhdr ( .* );
      rvdff #(WIDTH) dff (.*, .clk(l1clk));
`ifndef PHYSICAL
   end
   else 
      $error("%m: rvdffe width must be >= 8");
`endif

`endif
   
endmodule // rvdffe

module rvsyncss #(parameter WIDTH = 251)
   ( 
     input  logic                 clk,
     input  logic                 rst_l,
     input  logic [WIDTH-1:0]     din,
     output logic [WIDTH-1:0]     dout  
     );
   
   logic [WIDTH-1:0] 		  din_ff1;

   rvdff #(WIDTH) sync_ff1  (.*, .din (din[WIDTH-1:0]),     .dout(din_ff1[WIDTH-1:0]));
   rvdff #(WIDTH) sync_ff2  (.*, .din (din_ff1[WIDTH-1:0]), .dout(dout[WIDTH-1:0]));
   
endmodule // rvsyncss

module rvlsadder
  ( 
    input logic [31:0] rs1,
    input logic [11:0] offset,

    output logic [31:0] dout
    );

   logic 		cout;
   logic 		sign;
   
   logic [31:12] 	rs1_inc;
   logic [31:12] 	rs1_dec;

   assign {cout,dout[11:0]} = {1'b0,rs1[11:0]} + {1'b0,offset[11:0]};

   assign rs1_inc[31:12] = rs1[31:12] + 1;

   assign rs1_dec[31:12] = rs1[31:12] - 1;

   assign sign = offset[11];

   assign dout[31:12] = ({20{  sign ^~  cout}} &     rs1[31:12]) |
			({20{ ~sign &   cout}}  & rs1_inc[31:12]) |
			({20{  sign &  ~cout}}  & rs1_dec[31:12]);
      
endmodule // rvlsadder

// assume we only maintain pc[31:1] in the pipe

module rvbradder
  ( 
    input [31:1] pc,
    input [12:1] offset,

    output [31:1] dout
    );

   logic 	  cout;
   logic 	  sign;
   
   logic [31:13]  pc_inc;
   logic [31:13]  pc_dec;

   assign {cout,dout[12:1]} = {1'b0,pc[12:1]} + {1'b0,offset[12:1]};

   assign pc_inc[31:13] = pc[31:13] + 1;

   assign pc_dec[31:13] = pc[31:13] - 1;

   assign sign = offset[12];


   assign dout[31:13] = ({19{  sign ^~  cout}} &     pc[31:13]) |
			({19{ ~sign &   cout}}  & pc_inc[31:13]) |
			({19{  sign &  ~cout}}  & pc_dec[31:13]);
   
   
endmodule // rvbradder


// 2s complement circuit
module rvtwoscomp #( parameter WIDTH=32 )
   ( 
     input logic [WIDTH-1:0] din,

     output logic [WIDTH-1:0] dout
     );
   
   logic [WIDTH-1:1] 	      dout_temp;   // holding for all other bits except for the lsb. LSB is always din
   
   genvar 		      i;
   
   for ( i = 1; i < WIDTH; i++ )  begin : flip_after_first_one
      assign dout_temp[i] = (|din[i-1:0]) ? ~din[i] : din[i];
   end : flip_after_first_one
   
   assign dout[WIDTH-1:0]  = { dout_temp[WIDTH-1:1], din[0] };

endmodule  // 2'scomp

// find first
module rvfindfirst1 #( parameter WIDTH=32, SHIFT=$clog2(WIDTH) )
   ( 
     input logic [WIDTH-1:0] din,

     output logic [SHIFT-1:0] dout
     );
   logic 		      done;
   
   always_comb begin
      dout[SHIFT-1:0] = {SHIFT{1'b0}};
      done    = 1'b0;
      
      for ( int i = WIDTH-1; i > 0; i-- )  begin : find_first_one
	 done |= din[i];
	 dout[SHIFT-1:0] += done ? 1'b0 : 1'b1;
      end : find_first_one
   end
endmodule // rvfindfirst1

module rvfindfirst1hot #( parameter WIDTH=32 )
   ( 
     input logic [WIDTH-1:0] din,

     output logic [WIDTH-1:0] dout
     );
   logic 		      done;
   
   always_comb begin
      dout[WIDTH-1:0] = {WIDTH{1'b0}};
      done    = 1'b0;
      for ( int i = 0; i < WIDTH; i++ )  begin : find_first_one
	 dout[i] = ~done & din[i];
	 done   |= din[i];    
      end : find_first_one
   end
endmodule // rvfindfirst1hot

// mask and match function matches bits after finding the first 0 position
// find first starting from LSB. Skip that location and match the rest of the bits
module rvmaskandmatch #( parameter WIDTH=32 )
   ( 
     input  logic [WIDTH-1:0] mask,     // this will have the mask in the lower bit positions
     input  logic [WIDTH-1:0] data,     // this is what needs to be matched on the upper bits with the mask's upper bits
     input  logic             masken,   // when 1 : do mask. 0 : full match 
     output logic             match 
     );
   
   logic [WIDTH-1:0] 	      matchvec;   
   logic 		      masken_or_fullmask;
   
   assign masken_or_fullmask = masken &  ~(&mask[WIDTH-1:0]);
   
   assign matchvec[0]        = masken_or_fullmask | (mask[0] == data[0]);
   genvar 		      i;
   
   for ( i = 1; i < WIDTH; i++ )  begin : match_after_first_zero
      assign matchvec[i] = (&mask[i-1:0] & masken_or_fullmask) ? 1'b1 : (mask[i] == data[i]);
   end : match_after_first_zero
   
   assign match  = &matchvec[WIDTH-1:0];    // all bits either matched or were masked off

endmodule // rvmaskandmatch

module rvbtb_tag_hash (
		       input logic [31:1] pc,
		       output logic [`RV_BTB_BTAG_SIZE-1:0] hash
		       );
`ifndef RV_BTB_BTAG_FOLD
    assign hash = {(pc[`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE+`RV_BTB_BTAG_SIZE+`RV_BTB_BTAG_SIZE:`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE+`RV_BTB_BTAG_SIZE+1] ^ 
		   pc[`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE+`RV_BTB_BTAG_SIZE:`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE+1] ^ 
		   pc[`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE:`RV_BTB_ADDR_HI+1])};
`else
    assign hash = {(
		   pc[`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE+`RV_BTB_BTAG_SIZE:`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE+1] ^ 
		   pc[`RV_BTB_ADDR_HI+`RV_BTB_BTAG_SIZE:`RV_BTB_ADDR_HI+1])};
`endif
   
//  assign hash = {pc[`RV_BTB_ADDR_HI+1],(pc[`RV_BTB_ADDR_HI+13:`RV_BTB_ADDR_HI+10] ^ 
//					 pc[`RV_BTB_ADDR_HI+9:`RV_BTB_ADDR_HI+6] ^ 
//					 pc[`RV_BTB_ADDR_HI+5:`RV_BTB_ADDR_HI+2])};

endmodule

module rvbtb_addr_hash (
			input logic [31:1] pc,
			output logic [`RV_BTB_ADDR_HI:`RV_BTB_ADDR_LO] hash
			);

   assign hash[`RV_BTB_ADDR_HI:`RV_BTB_ADDR_LO] = pc[`RV_BTB_INDEX1_HI:`RV_BTB_INDEX1_LO] ^ 

`ifndef RV_BTB_FOLD2_INDEX_HASH						  
						  pc[`RV_BTB_INDEX2_HI:`RV_BTB_INDEX2_LO] ^ 
`endif
						    
						  pc[`RV_BTB_INDEX3_HI:`RV_BTB_INDEX3_LO];

endmodule

module rvbtb_ghr_hash (
		       input logic [`RV_BTB_ADDR_HI:`RV_BTB_ADDR_LO] hashin,
		       input logic [`RV_BHT_GHR_RANGE] ghr,
		       output logic [`RV_BHT_ADDR_HI:`RV_BHT_ADDR_LO] hash
		       );

   // The hash function is too complex to write in verilog for all cases.
   // The config script generates the logic string based on the bp config.
   assign hash[`RV_BHT_ADDR_HI:`RV_BHT_ADDR_LO] = `RV_BHT_HASH_STRING;

endmodule


// Check if the S_ADDR <= addr < E_ADDR
module rvrangecheck  #(CCM_SADR = 32'h0,
                       CCM_SIZE  = 128) ( 
   input  logic [31:0]   addr,                             // Address to be checked for range
   output logic          in_range,                            // S_ADDR <= start_addr < E_ADDR
   output logic          in_region                          
);

   localparam REGION_BITS = 4;
   localparam MASK_BITS = 10 + $clog2(CCM_SIZE);

   logic [31:0]          start_addr;
   logic [3:0]           region;
   
   assign start_addr[31:0]        = CCM_SADR;
   assign region[REGION_BITS-1:0] = start_addr[31:(32-REGION_BITS)];

   assign in_region = (addr[31:(32-REGION_BITS)] == region[REGION_BITS-1:0]); 
   if (CCM_SIZE  == 48)
    assign in_range  = (addr[31:MASK_BITS] == start_addr[31:MASK_BITS]) & ~(&addr[MASK_BITS-1 : MASK_BITS-2]);
   else
    assign in_range  = (addr[31:MASK_BITS] == start_addr[31:MASK_BITS]);
   
endmodule  // rvrangechecker

// 16 bit even parity generator
module rveven_paritygen #(WIDTH = 16)  ( 
					 input  logic [WIDTH-1:0]  data_in,         // Data
					 output logic              parity_out       // generated even parity
					 );
   
   assign  parity_out =  ^(data_in[WIDTH-1:0]) ;
   
endmodule  // rveven_paritygen

module rveven_paritycheck #(WIDTH = 16)  ( 
					   input  logic [WIDTH-1:0]  data_in,         // Data
					   input  logic              parity_in,
					   output logic              parity_err       // Parity error
					   );
   
   assign  parity_err =  ^(data_in[WIDTH-1:0]) ^ parity_in ;
   
endmodule  // rveven_paritycheck

module rvecc_encode  (
		      input [31:0] din,
		      output [6:0] ecc_out
		      );  
logic [5:0] ecc_out_temp;

   assign ecc_out_temp[0] = din[0]^din[1]^din[3]^din[4]^din[6]^din[8]^din[10]^din[11]^din[13]^din[15]^din[17]^din[19]^din[21]^din[23]^din[25]^din[26]^din[28]^din[30];
   assign ecc_out_temp[1] = din[0]^din[2]^din[3]^din[5]^din[6]^din[9]^din[10]^din[12]^din[13]^din[16]^din[17]^din[20]^din[21]^din[24]^din[25]^din[27]^din[28]^din[31];
   assign ecc_out_temp[2] = din[1]^din[2]^din[3]^din[7]^din[8]^din[9]^din[10]^din[14]^din[15]^din[16]^din[17]^din[22]^din[23]^din[24]^din[25]^din[29]^din[30]^din[31];
   assign ecc_out_temp[3] = din[4]^din[5]^din[6]^din[7]^din[8]^din[9]^din[10]^din[18]^din[19]^din[20]^din[21]^din[22]^din[23]^din[24]^din[25];
   assign ecc_out_temp[4] = din[11]^din[12]^din[13]^din[14]^din[15]^din[16]^din[17]^din[18]^din[19]^din[20]^din[21]^din[22]^din[23]^din[24]^din[25];
   assign ecc_out_temp[5] = din[26]^din[27]^din[28]^din[29]^din[30]^din[31];

   assign ecc_out[6:0] = {(^din[31:0])^(^ecc_out_temp[5:0]),ecc_out_temp[5:0]};

endmodule // rvecc_encode

module rvecc_decode  (
		      input         en,
		      input [31:0]  din,
		      input [6:0]   ecc_in,
                      input         sed_ded,    // only do detection and no correction. Used for the I$
		      output [31:0] dout,
                      output [6:0]  ecc_out,
		      output        single_ecc_error,
		      output        double_ecc_error

		      );

   logic [6:0] 			    ecc_check;
   logic [38:0] 		    error_mask;
   logic [38:0] 		    din_plus_parity, dout_plus_parity;
   
   // Generate the ecc bits
   assign ecc_check[0] = ecc_in[0]^din[0]^din[1]^din[3]^din[4]^din[6]^din[8]^din[10]^din[11]^din[13]^din[15]^din[17]^din[19]^din[21]^din[23]^din[25]^din[26]^din[28]^din[30];
   assign ecc_check[1] = ecc_in[1]^din[0]^din[2]^din[3]^din[5]^din[6]^din[9]^din[10]^din[12]^din[13]^din[16]^din[17]^din[20]^din[21]^din[24]^din[25]^din[27]^din[28]^din[31];
   assign ecc_check[2] = ecc_in[2]^din[1]^din[2]^din[3]^din[7]^din[8]^din[9]^din[10]^din[14]^din[15]^din[16]^din[17]^din[22]^din[23]^din[24]^din[25]^din[29]^din[30]^din[31];
   assign ecc_check[3] = ecc_in[3]^din[4]^din[5]^din[6]^din[7]^din[8]^din[9]^din[10]^din[18]^din[19]^din[20]^din[21]^din[22]^din[23]^din[24]^din[25];
   assign ecc_check[4] = ecc_in[4]^din[11]^din[12]^din[13]^din[14]^din[15]^din[16]^din[17]^din[18]^din[19]^din[20]^din[21]^din[22]^din[23]^din[24]^din[25];
   assign ecc_check[5] = ecc_in[5]^din[26]^din[27]^din[28]^din[29]^din[30]^din[31];

   // This is the parity bit
   assign ecc_check[6] = ((^din[31:0])^(^ecc_in[6:0])) & ~sed_ded;

   assign single_ecc_error = en & (ecc_check[6:0] != 0) & ecc_check[6];   // this will never be on for sed_ded
   assign double_ecc_error = en & (ecc_check[6:0] != 0) & ~ecc_check[6];  // all errors in the sed_ded case will be recorded as DE 
   
   // Generate the mask for error correctiong
   for (genvar i=1; i<40; i++) begin
      assign error_mask[i-1] = (ecc_check[5:0] == i);
   end

   // Generate the corrected data
   assign din_plus_parity[38:0] = {ecc_in[6], din[31:26], ecc_in[5], din[25:11], ecc_in[4], din[10:4], ecc_in[3], din[3:1], ecc_in[2], din[0], ecc_in[1:0]};
   
   assign dout_plus_parity[38:0] = single_ecc_error ? (error_mask[38:0] ^ din_plus_parity[38:0]) : din_plus_parity[38:0];
   assign dout[31:0]             = {dout_plus_parity[37:32], dout_plus_parity[30:16], dout_plus_parity[14:8], dout_plus_parity[6:4], dout_plus_parity[2]};
   assign ecc_out[6:0]           = {(dout_plus_parity[38] ^ (ecc_check[6:0] == 7'b1000000)), dout_plus_parity[31], dout_plus_parity[15], dout_plus_parity[7], dout_plus_parity[3], dout_plus_parity[1:0]};
   
endmodule // rvecc_decode