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// ========== Copyright Header Begin ==========================================

// 

// OpenSPARC T1 Processor File: sparc_exu_ecl_eccctl.v

// Copyright (c) 2006 Sun Microsystems, Inc.  All Rights Reserved.

// DO NOT ALTER OR REMOVE COPYRIGHT NOTICES.

// 

// The above named program is free software; you can redistribute it and/or

// modify it under the terms of the GNU General Public

// License version 2 as published by the Free Software Foundation.

// 

// The above named program is distributed in the hope that it will be 

// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

// General Public License for more details.

// 

// You should have received a copy of the GNU General Public

// License along with this work; if not, write to the Free Software

// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

// 

// ========== Copyright Header End ============================================

////////////////////////////////////////////////////////////////////////

/*

//  Module Name: sparc_exu_ecl_eccctl

//      Description:  Implements the control logic for ecc checking.

//              This includes picking which error to fix (only one fixed per instruction),

//              enabling the checks, and signalling the errors.

*/

module sparc_exu_ecl_eccctl (/*AUTOARG*/

   // Outputs

   ue_trap_m, ecl_ecc_sel_rs1_m_l, ecl_ecc_sel_rs2_m_l,

   ecl_ecc_sel_rs3_m_l, ecl_ecc_log_rs1_m, ecl_ecc_log_rs2_m,

   ecl_ecc_log_rs3_m, ecl_byp_sel_ecc_m, ecl_ecc_rs1_use_rf_e,

   ecl_ecc_rs2_use_rf_e, ecl_ecc_rs3_use_rf_e, eccctl_wb_rd_m,

   exu_ifu_ecc_ce_m, exu_ifu_ecc_ue_m, exu_ifu_err_reg_m,

   ecl_byp_ecc_mask_m_l, exu_ifu_inj_ack, exu_ifu_err_synd_7_m,

   // Inputs

   clk, se, rst_tri_en, ecc_ecl_rs1_ce, ecc_ecl_rs1_ue,

   ecc_ecl_rs2_ce, ecc_ecl_rs2_ue, ecc_ecl_rs3_ce, ecc_ecl_rs3_ue,

   ecl_byp_rcc_mux2_sel_rf, ecl_byp_rs2_mux2_sel_rf,

   ecl_byp_rs3_mux2_sel_rf, rs1_vld_e, rs2_vld_e, rs3_vld_e,

   ifu_exu_rs1_m, ifu_exu_rs2_m, ifu_exu_rs3_m, rml_ecl_cwp_d,

   ifu_exu_ecc_mask, ifu_exu_inj_irferr, ifu_exu_disable_ce_e,

   wb_eccctl_spec_wen_next, ifu_exu_nceen_e, ifu_exu_inst_vld_e,

   rml_ecl_gl_e, cancel_rs3_ecc_e

   ) ;

   input clk;

   input se;

   input rst_tri_en;

   input       ecc_ecl_rs1_ce;

   input       ecc_ecl_rs1_ue;

   input       ecc_ecl_rs2_ce;

   input       ecc_ecl_rs2_ue;

   input       ecc_ecl_rs3_ce;

   input       ecc_ecl_rs3_ue;

   input       ecl_byp_rcc_mux2_sel_rf;

   input       ecl_byp_rs2_mux2_sel_rf;

   input       ecl_byp_rs3_mux2_sel_rf;

   input       rs1_vld_e;

   input       rs2_vld_e;

   input       rs3_vld_e;

   input [4:0] ifu_exu_rs1_m;

   input [4:0] ifu_exu_rs2_m;

   input [4:0] ifu_exu_rs3_m;

   input [2:0] rml_ecl_cwp_d;

   input [7:0] ifu_exu_ecc_mask;

   input       ifu_exu_inj_irferr;

   input       ifu_exu_disable_ce_e;

   input       wb_eccctl_spec_wen_next;

   input       ifu_exu_nceen_e;

   input       ifu_exu_inst_vld_e;

   input [1:0] rml_ecl_gl_e;

   input       cancel_rs3_ecc_e;

   output      ue_trap_m;

   output      ecl_ecc_sel_rs1_m_l;

   output      ecl_ecc_sel_rs2_m_l;

   output      ecl_ecc_sel_rs3_m_l;

   output      ecl_ecc_log_rs1_m;

   output      ecl_ecc_log_rs2_m;

   output      ecl_ecc_log_rs3_m;

   output      ecl_byp_sel_ecc_m;

   output      ecl_ecc_rs1_use_rf_e;

   output      ecl_ecc_rs2_use_rf_e;

   output      ecl_ecc_rs3_use_rf_e;

   output [4:0] eccctl_wb_rd_m;

   output       exu_ifu_ecc_ce_m;

   output       exu_ifu_ecc_ue_m;

   output [7:0] exu_ifu_err_reg_m;

   output [7:0] ecl_byp_ecc_mask_m_l;

   output       exu_ifu_inj_ack;

   output    exu_ifu_err_synd_7_m;

   wire      sel_rs1_e;

   wire      sel_rs2_e;

   wire      sel_rs3_e;

   wire        sel_rs1_m;

   wire        sel_rs2_m;

   wire        sel_rs3_m;

   wire        safe_sel_rs1_m;

   wire        safe_sel_rs2_m;

   wire        safe_sel_rs3_m;

   wire [2:0]  cwp_e;

   wire [2:0]  cwp_m;

   wire [1:0]  gl_m;

   wire        inj_irferr_m;

   wire        inj_irferr_w;

   wire        detect_ce_e;

   wire        detect_ue_e;

   wire        flag_ecc_ce_e;

   wire        flag_ecc_ue_e;

   wire [4:0]  log_rs_m;

   wire        rs1_ce_m;

   wire        rs1_ue_m;

   wire        rs2_ce_m;

   wire        rs2_ue_m;

   wire        rs3_ue_m;

   wire        rs1_sel_rf_e;

   wire        rs2_sel_rf_e;

   wire        rs3_sel_rf_e;

   wire        vld_rs3_ce_e;

   wire        vld_rs3_ue_e;

   // Store whether rf value was used for ecc checking

   assign      ecl_ecc_rs1_use_rf_e = rs1_sel_rf_e & rs1_vld_e & ifu_exu_inst_vld_e;

   assign      ecl_ecc_rs2_use_rf_e = rs2_sel_rf_e & rs2_vld_e & ifu_exu_inst_vld_e;

   assign      ecl_ecc_rs3_use_rf_e = rs3_sel_rf_e & rs3_vld_e & ifu_exu_inst_vld_e;

   dff_s rs1_rf_dff(.din(ecl_byp_rcc_mux2_sel_rf), .clk(clk),

                  .q(rs1_sel_rf_e), .se(se), .si(), .so());

   dff_s rs2_rf_dff(.din(ecl_byp_rs2_mux2_sel_rf), .clk(clk),

                  .q(rs2_sel_rf_e), .se(se), .si(), .so());

   dff_s rs3_rf_dff(.din(ecl_byp_rs3_mux2_sel_rf), .clk(clk),

                  .q(rs3_sel_rf_e), .se(se), .si(), .so());

   assign      vld_rs3_ce_e = ecc_ecl_rs3_ce & ~cancel_rs3_ecc_e;

   assign      vld_rs3_ue_e = ecc_ecl_rs3_ue & ~cancel_rs3_ecc_e;

   assign    detect_ce_e = (ecc_ecl_rs1_ce | ecc_ecl_rs2_ce | vld_rs3_ce_e);

   assign    detect_ue_e = (ecc_ecl_rs1_ue | ecc_ecl_rs2_ue | vld_rs3_ue_e);

   // Generate trap signals

   assign    flag_ecc_ue_e = (detect_ue_e |

                                    detect_ce_e & ifu_exu_disable_ce_e); // convert ce to ue

   assign    flag_ecc_ce_e = detect_ce_e & ~ifu_exu_disable_ce_e;

   // Pass along signal to fix errors

   dff_s byp_sel_ecc_e2m(.din(flag_ecc_ce_e), .clk(clk), .q(ecl_byp_sel_ecc_m),

                       .se(se), .si(), .so());

   dff_s ecc_ue_e2m(.din(flag_ecc_ue_e), .clk(clk), .q(exu_ifu_ecc_ue_m),

                  .se(se), .si(), .so());

   dff_s nceen_e2m(.din(ifu_exu_nceen_e), .clk(clk), .q(nceen_m), .se(se), .si(), .so());

   assign    ue_trap_m = exu_ifu_ecc_ue_m & nceen_m;

   // only report ce (and replay) if no ue

   assign      exu_ifu_ecc_ce_m = ecl_byp_sel_ecc_m & ~exu_ifu_ecc_ue_m;

   // if globals then report %gl.  otherwise log %cwp

   assign      exu_ifu_err_reg_m[7:5] = (~log_rs_m[4] & ~log_rs_m[3])? {1'b0,gl_m[1:0]}: cwp_m[2:0];

   assign      exu_ifu_err_reg_m[4:0] = log_rs_m[4:0];

   // Control for mux to ecc decoder (just ce)

   assign      sel_rs1_e = ecc_ecl_rs1_ce;

   assign      sel_rs2_e = ~ecc_ecl_rs1_ce & ecc_ecl_rs2_ce;

   assign      sel_rs3_e = ~(ecc_ecl_rs1_ce | ecc_ecl_rs2_ce);

   dff_s ecc_sel_rs1_dff(.din(sel_rs1_e), .clk(clk), .q(sel_rs1_m),

                       .se(se), .si(), .so());

   dff_s ecc_sel_rs2_dff(.din(sel_rs2_e), .clk(clk), .q(sel_rs2_m),

                       .se(se), .si(), .so());

   dff_s ecc_sel_rs3_dff(.din(sel_rs3_e), .clk(clk), .q(sel_rs3_m),

                       .se(se), .si(), .so());

   // Make selects one hot

   assign      safe_sel_rs1_m = sel_rs1_m | rst_tri_en;

   assign      safe_sel_rs2_m = sel_rs2_m & ~rst_tri_en;

   assign      safe_sel_rs3_m = sel_rs3_m & ~rst_tri_en;

   assign      ecl_ecc_sel_rs1_m_l = ~safe_sel_rs1_m;

   assign      ecl_ecc_sel_rs2_m_l = ~safe_sel_rs2_m;

   assign      ecl_ecc_sel_rs3_m_l = ~safe_sel_rs3_m;

   // Mux to generate the rd for fixed value

   mux3ds #(5) ecc_rd_mux(.dout(eccctl_wb_rd_m[4:0]),

                          .in0(ifu_exu_rs1_m[4:0]),

                          .in1(ifu_exu_rs2_m[4:0]),

                          .in2(ifu_exu_rs3_m[4:0]),

                          .sel0(safe_sel_rs1_m),

                          .sel1(safe_sel_rs2_m),

                          .sel2(safe_sel_rs3_m));

   // Control for muxes for logging errors

   assign      ecl_ecc_log_rs1_m = rs1_ue_m | (rs1_ce_m & ~rs2_ue_m & ~rs3_ue_m);

   assign      ecl_ecc_log_rs2_m = (rs2_ue_m & ~rs1_ue_m) | (rs2_ce_m & ~rs1_ue_m & ~rs1_ce_m & ~rs3_ue_m);

   assign      ecl_ecc_log_rs3_m = ~(ecl_ecc_log_rs1_m | ecl_ecc_log_rs2_m);

   // Mux to generate the rs for error_logging

   mux3ds #(5) ecc_rdlog_mux(.dout(log_rs_m[4:0]),

                          .in0(ifu_exu_rs1_m[4:0]),

                          .in1(ifu_exu_rs2_m[4:0]),

                          .in2(ifu_exu_rs3_m[4:0]),

                          .sel0(ecl_ecc_log_rs1_m),

                          .sel1(ecl_ecc_log_rs2_m),

                          .sel2(ecl_ecc_log_rs3_m));

   dff_s #(3) cwp_d2e(.din(rml_ecl_cwp_d[2:0]), .clk(clk), .q(cwp_e[2:0]),

                    .se(se), .si(), .so());

   dff_s #(3) cwp_e2m(.din(cwp_e[2:0]), .clk(clk), .q(cwp_m[2:0]),

                    .se(se), .si(), .so());

   dff_s #(2) gl_e2m(.din(rml_ecl_gl_e[1:0]), .clk(clk), .q(gl_m[1:0]),

                   .se(se), .si(), .so());

   // Syndrome needs to know if it was really a ce or ue

   mux3ds ecc_synd7_mux(.dout(exu_ifu_err_synd_7_m),

                        .in0(rs1_ce_m),

                        .in1(rs2_ce_m),

                        .in2(~rs3_ue_m),

                        .sel0(ecl_ecc_log_rs1_m),

                        .sel1(ecl_ecc_log_rs2_m),

                        .sel2(ecl_ecc_log_rs3_m));

   // signals for injecting errors

   // inject error if it is enabled and a write will probably happen

   // (don't bother to check kill_w

   assign      inj_irferr_m = wb_eccctl_spec_wen_next & ifu_exu_inj_irferr;

   assign      ecl_byp_ecc_mask_m_l = ~(ifu_exu_ecc_mask[7:0] & {8{inj_irferr_m}});

   dff_s inj_irferr_m2w(.din(inj_irferr_m), .clk(clk), .q(inj_irferr_w),

                      .se(se), .si(), .so());

   assign      exu_ifu_inj_ack = inj_irferr_w;

   // Pipeline Flops

   dff_s rs1_ue_e2m(.din(ecc_ecl_rs1_ue), .clk(clk), .q(rs1_ue_m), .se(se), .si(), .so());

   dff_s rs1_ce_e2m(.din(ecc_ecl_rs1_ce), .clk(clk), .q(rs1_ce_m), .se(se), .si(), .so());

   dff_s rs2_ue_e2m(.din(ecc_ecl_rs2_ue), .clk(clk), .q(rs2_ue_m), .se(se), .si(), .so());

   dff_s rs2_ce_e2m(.din(ecc_ecl_rs2_ce), .clk(clk), .q(rs2_ce_m), .se(se), .si(), .so());

   dff_s rs3_ue_e2m(.din(vld_rs3_ue_e), .clk(clk), .q(rs3_ue_m), .se(se), .si(), .so());

endmodule // sparc_exu_ecl_eccctl