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

// 

// OpenSPARC T1 Processor File: sparc_ffu_dp.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_ffu_dp

//      Description: This is the ffu datapath.  It stores the 2 128 bit operands

//      and the result (puts result in the 1st source to save space).

*/

`include "iop.h"

module sparc_ffu_dp (/*AUTOARG*/

   // Outputs

   so, dp_frf_data, ffu_lsu_data, dp_vis_rs1_data, dp_vis_rs2_data,

   dp_ctl_rs2_sign, dp_ctl_fsr_fcc, dp_ctl_fsr_rnd, dp_ctl_fsr_tem,

   dp_ctl_fsr_aexc, dp_ctl_fsr_cexc, dp_ctl_ld_fcc,

   dp_ctl_gsr_mask_e, dp_ctl_gsr_scale_e, dp_ctl_synd_out_low,

   dp_ctl_synd_out_high,

   // Inputs

   rclk, se, si, ctl_dp_rst_l, frf_dp_data, cpx_fpu_data,

   lsu_ffu_ld_data, vis_dp_rd_data, ctl_dp_wsr_data_w2, ctl_dp_sign,

   ctl_dp_exc_w2, ctl_dp_fcc_w2, ctl_dp_ftt_w2, ctl_dp_noshift64_frf,

   ctl_dp_shift_frf_right, ctl_dp_shift_frf_left,

   ctl_dp_zero_low32_frf, ctl_dp_output_sel_rs1,

   ctl_dp_output_sel_rs2, ctl_dp_output_sel_frf,

   ctl_dp_output_sel_fsr, ctl_dp_noflip_lsu, ctl_dp_flip_lsu,

   ctl_dp_noflip_fpu, ctl_dp_flip_fpu, ctl_dp_rs2_frf_read,

   ctl_dp_rs2_sel_vis, ctl_dp_rs2_sel_fpu_lsu, ctl_dp_rs2_keep_data,

   ctl_dp_rd_ecc, ctl_dp_fp_thr, ctl_dp_fsr_sel_old,

   ctl_dp_fsr_sel_ld, ctl_dp_fsr_sel_fpu, ctl_dp_gsr_wsr_w2,

   ctl_dp_thr_e, ctl_dp_new_rs1, ctl_dp_ecc_sel_frf

   ) ;

   input rclk;

   input se;

   input si;

   input ctl_dp_rst_l;

   input [77:0] frf_dp_data;

   input [63:0]   cpx_fpu_data;

   input [63:0] lsu_ffu_ld_data;

   input [63:0] vis_dp_rd_data;

   input [36:0] ctl_dp_wsr_data_w2;

   input [1:0]   ctl_dp_sign;  // sign after abs or neg

   input [9:0]    ctl_dp_exc_w2;

   input [7:0]    ctl_dp_fcc_w2;

   input [2:0]    ctl_dp_ftt_w2;

   // mux selects

   input         ctl_dp_noshift64_frf;     // choose output from FRF

   input         ctl_dp_shift_frf_right;

   input         ctl_dp_shift_frf_left;

   input         ctl_dp_zero_low32_frf;

   input         ctl_dp_output_sel_rs1;  // choose output to lsu

   input         ctl_dp_output_sel_rs2;

   input         ctl_dp_output_sel_frf;

   input         ctl_dp_output_sel_fsr;

   input         ctl_dp_noflip_lsu;// inputs from lsu and fpu

   input         ctl_dp_flip_lsu;

   input         ctl_dp_noflip_fpu;

   input         ctl_dp_flip_fpu;

   input         ctl_dp_rs2_frf_read;    // choose r2

   input         ctl_dp_rs2_sel_vis;

   input         ctl_dp_rs2_sel_fpu_lsu;

   input         ctl_dp_rs2_keep_data;

   input         ctl_dp_rd_ecc;

   input [3:0]    ctl_dp_fp_thr;

   input [3:0]    ctl_dp_fsr_sel_old,     // choose what to update FSR with

                 ctl_dp_fsr_sel_ld,

                 ctl_dp_fsr_sel_fpu;

   input [3:0]   ctl_dp_gsr_wsr_w2;

   input [3:0]   ctl_dp_thr_e;

   // rs1 selects

   input         ctl_dp_new_rs1;

   // 2:1 mux selects

   input      ctl_dp_ecc_sel_frf;

   // outputs

   output       so;

   output [63:0] dp_frf_data;

   output [63:0] ffu_lsu_data;

   output [63:0] dp_vis_rs1_data;

   output [63:0] dp_vis_rs2_data;

   output [1:0]  dp_ctl_rs2_sign;  // sign for rs2

   output [7:0]  dp_ctl_fsr_fcc;

   output [1:0]  dp_ctl_fsr_rnd;

   output [4:0]  dp_ctl_fsr_tem;

   output [4:0]  dp_ctl_fsr_aexc;

   output [4:0]  dp_ctl_fsr_cexc;

   output [7:0]  dp_ctl_ld_fcc;

   output [31:0] dp_ctl_gsr_mask_e;

   output [4:0]  dp_ctl_gsr_scale_e;

   output [6:0] dp_ctl_synd_out_low;   // signals for ecc errors

   output [6:0] dp_ctl_synd_out_high;

   wire         clk;

   wire         reset;

   // local signals

   wire [63:0]    fpu_ffu_data;

   wire [63:0]   lsu_ffu_ld_data_d1;

   wire [63:0]   rs2_rd_data;  // stores both the rs2 and rd data

   wire [63:0]   rs2_rd_data_next;

   wire [63:0]   write_data;    // needed since block loads are pipelined

   wire [63:0]   rs2_data_changed;

   wire [63:0]   local_rd_data;

   wire [63:0]   rs1_data;

   wire [63:0]   rs1_data_next;

   wire [63:0]   shifted_frf_data;

   wire [63:0]   new_frf_data;

   wire [63:0]   lsu_fpu_data;

   wire [63:0]   frf_data_in;

   wire [6:0]    synd_in_low;   // input ecc for lower word

   wire [6:0]    synd_in_h;   // input ecc for upper word

   wire [63:0] corr_data_next;

   wire [63:0] corr_data;

   wire [63:0] ecc_data_in;

   wire [27:0]    current_fsr,

                 t0_fsr,

                 t1_fsr,

                 t2_fsr,

                 t3_fsr;

   wire [27:0]    t0_fsr_nxt,

                 t1_fsr_nxt,

                 t2_fsr_nxt,

                 t3_fsr_nxt;

   wire [27:0]    t0_ldfsr_data,

                             t0_fpufsr_data;

   wire [27:0]    t1_ldfsr_data,

                             t1_fpufsr_data;

   wire [27:0]    t2_ldfsr_data,

                             t2_fpufsr_data;

   wire [27:0]    t3_ldfsr_data,

                             t3_fpufsr_data;

   wire [36:0]   gsr_e;

   wire [36:0]   t0_gsr;

   wire [36:0]   t0_gsr_nxt;

   wire [36:0]   t1_gsr;

   wire [36:0]   t1_gsr_nxt;

   wire [36:0]   t2_gsr;

   wire [36:0]   t2_gsr_nxt;

   wire [36:0]   t3_gsr;

   wire [36:0]   t3_gsr_nxt;

   assign        reset = ~ctl_dp_rst_l;

   assign        clk= rclk;

   dff_s #(64) cpx_reg(.din(cpx_fpu_data[63:0]),

                                       .q   (fpu_ffu_data[63:0]),

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

   // flop for lsu data.  the data is flopped in ffu, but the vld is flopped in the lsu.

   // This is for timing reasons on the valid bit and Sanjay didn't want to redo the

   // lsu dp for the data portion

   dff_s #(64) lsu_data_dff(.din(lsu_ffu_ld_data[63:0]), .clk(clk), .q(lsu_ffu_ld_data_d1[63:0]),

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

   assign dp_ctl_ld_fcc[7:0] = {lsu_ffu_ld_data_d1[37:32], lsu_ffu_ld_data_d1[11:10]};

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

   //   Input from FRF (shift as needed for singles)

   //   The data needs to be shifted around because these are 64 bit reads but

   //   the required data might be in either the upper or lower 32 bits for

   //   singles.  If it is a double then the data is left alone.

   //   If it is a single move and the source and target have the same alignment

   //   then no change happens.  If it is a single move and the source and target

   //   have different alignments the operands get moved into place for the write.

   //   If it is data that will be sent to the lsu the data is moved into the lower

   //   32 bits.  If the data will be sent to the fpu the data is moved to the upper

   //   32 bits (if not there already)

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

   assign  frf_data_in[63:32] = frf_dp_data[70:39];

   assign  frf_data_in[31:0] = frf_dp_data[31:0];

   mux3ds #(64) frf_input_mux(.dout(shifted_frf_data[63:0]),

                              .in0(frf_data_in[63:0]),

                              .in1({32'b0, frf_data_in[63:32]}),

                              .in2({frf_data_in[31:0], 32'b0}),

                              .sel0(ctl_dp_noshift64_frf),

                              .sel1(ctl_dp_shift_frf_right),

                              .sel2(ctl_dp_shift_frf_left));

   assign  new_frf_data[63:32] = shifted_frf_data[63:32];

   assign  new_frf_data[31:0] = shifted_frf_data[31:0] & {32{~ctl_dp_zero_low32_frf}};

   mux4ds #(64) lsu_fpu_input_mux(.dout(lsu_fpu_data[63:0]),

                                  .in0(lsu_ffu_ld_data_d1[63:0]),

                                  .in1({lsu_ffu_ld_data_d1[31:0], 32'b0}),

                                  .in2(fpu_ffu_data[63:0]),

                                  .in3({32'b0, fpu_ffu_data[63:32]}),

                                  .sel0(ctl_dp_noflip_lsu),

                                  .sel1(ctl_dp_flip_lsu),

                                  .sel2(ctl_dp_noflip_fpu),

                                  .sel3(ctl_dp_flip_fpu));

   // Data to FRF

   dp_buffer #(64) frf_out_buf(.in(write_data[63:0]), .dout (dp_frf_data[63:0]));

   // Data to LSU

   // Mux for lsu data between two sets of data and the direct 

   // frf output for stores

   mux4ds #(64) output_mux(.dout (ffu_lsu_data[63:0]),

                           .in0  (rs2_rd_data[63:0]),

                           .in1  (rs1_data[63:0]),

                           .in2  (shifted_frf_data[63:0]),

                                             .in3  ({26'b0, current_fsr[27:20], 2'b0, current_fsr[19:15], 6'b0, current_fsr[14:12], 2'b0, current_fsr[11:0]}),

                           .sel0 (ctl_dp_output_sel_rs2),

                           .sel1 (ctl_dp_output_sel_rs1),

                           .sel2 (ctl_dp_output_sel_frf),

                                             .sel3 (ctl_dp_output_sel_fsr));

   // RS2 can take value from frf  (with modification to sign), from lsu 

   // or keep value

   // The modification to the sign bits allows for FABS and FNEG

   assign dp_ctl_rs2_sign[1:0] = {new_frf_data[63], new_frf_data[31]};

   assign rs2_data_changed[63:0] = {ctl_dp_sign[1], new_frf_data[62:32],

                                    ctl_dp_sign[0], new_frf_data[30:0]};

   dp_mux2es #(64) local_rd_mux(.dout(local_rd_data[63:0]),

                             .in0(rs2_data_changed[63:0]),

                             .in1(corr_data[63:0]),

                             .sel(ctl_dp_rd_ecc));

   mux4ds #(64) rs2_rd_mux(.dout (rs2_rd_data_next[63:0]),

                           .in0  (local_rd_data[63:0]),

                           .in1  (vis_dp_rd_data[63:0]),

                           .in2  (lsu_fpu_data[63:0]),

                           .in3  (rs2_rd_data[63:0]),

                           .sel0 (ctl_dp_rs2_frf_read),

                           .sel1 (ctl_dp_rs2_sel_vis),

                           .sel2 (ctl_dp_rs2_sel_fpu_lsu),

                           .sel3 (ctl_dp_rs2_keep_data));

   dff_s #(64) rs2_rd_dff(.din (rs2_rd_data_next[63:0]),

                                          .q   (rs2_rd_data[63:0]),

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

   assign dp_vis_rs2_data[63:0] = rs2_rd_data[63:0];

   dff_s #(64) write_data_dff(.din(rs2_rd_data[63:0]),

                            .q(write_data[63:0]),

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

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

   //                   RS1

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

   // RS1 next either takes value from frf or keeps value

   dp_mux2es #(64) rs1_mux(.dout (rs1_data_next[63:0]),

                           .in0  (rs1_data[63:0]),

                           .in1  (new_frf_data[63:0]),

                           .sel  (ctl_dp_new_rs1));

   dff_s #(64) rs1_dff(.din (rs1_data_next[63:0]),

                                 .q   (rs1_data[63:0]),

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

   assign dp_vis_rs1_data[63:0] = rs1_data[63:0];

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

   //                   FSR

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

   // FSR takes data from load

   // fsr is set by ldfsr, ldxfsr, or any fpu operation

   assign t0_ldfsr_data[27:0] = {ctl_dp_fcc_w2[7:2],     // fcc3,2,1

                                                   lsu_ffu_ld_data_d1[31:30],   // RND mode

                                                   //2'b0,                     // rsvd

                                                   lsu_ffu_ld_data_d1[27:23],   // TEM

                                                   //6'b0,                     // NS, rsvd, ver

                                                   t0_fsr[14:12],       // ftt

                                                   //2'b0,                     // qne, rsvd

                                                   lsu_ffu_ld_data_d1[11:0]};   // fcc0, aexc, cexc

   assign t0_fpufsr_data[27:0] = {ctl_dp_fcc_w2[7:2],

                                                    t0_fsr[21:20],  // rnd

                                                    t0_fsr[19:15],  // TEM

                                                    ctl_dp_ftt_w2[2:0],  // ftt

                                                    ctl_dp_fcc_w2[1:0],

                                                    ctl_dp_exc_w2[9:0]};

   assign t1_ldfsr_data[27:0] = {ctl_dp_fcc_w2[7:2],     // fcc3,2,1

                                                   lsu_ffu_ld_data_d1[31:30],   // RND mode

                                                   //2'b0,                     // rsvd

                                                   lsu_ffu_ld_data_d1[27:23],   // TEM

                                                   //6'b0,                     // NS, rsvd, ver

                                                   t1_fsr[14:12],       // ftt

                                                   //2'b0,                     // qne, rsvd

                                                   lsu_ffu_ld_data_d1[11:0]};   // fcc0, aexc, cexc

   assign t1_fpufsr_data[27:0] = {ctl_dp_fcc_w2[7:2],

                                                    t1_fsr[21:20],  // rnd

                                                    t1_fsr[19:15],  // TEM

                                                    ctl_dp_ftt_w2[2:0],  // ftt

                                                    ctl_dp_fcc_w2[1:0],

                                                    ctl_dp_exc_w2[9:0]};

   assign t2_ldfsr_data[27:0] = {ctl_dp_fcc_w2[7:2],     // fcc3,2,1

                                                   lsu_ffu_ld_data_d1[31:30],   // RND mode

                                                   //2'b0,                     // rsvd

                                                   lsu_ffu_ld_data_d1[27:23],   // TEM

                                                   //6'b0,                     // NS, rsvd, ver

                                                   t2_fsr[14:12],       // ftt

                                                   //2'b0,                     // qne, rsvd

                                                   lsu_ffu_ld_data_d1[11:0]};   // fcc0, aexc, cexc

   assign t2_fpufsr_data[27:0] = {ctl_dp_fcc_w2[7:2],

                                                    t2_fsr[21:20],  // rnd

                                                    t2_fsr[19:15],  // TEM

                                                    ctl_dp_ftt_w2[2:0],  // ftt

                                                    ctl_dp_fcc_w2[1:0],

                                                    ctl_dp_exc_w2[9:0]};

   assign t3_ldfsr_data[27:0] = {ctl_dp_fcc_w2[7:2],     // fcc3,2,1

                                                   lsu_ffu_ld_data_d1[31:30],   // RND mode

                                                   //2'b0,                     // rsvd

                                                   lsu_ffu_ld_data_d1[27:23],   // TEM

                                                   //6'b0,                     // NS, rsvd, ver

                                                   t3_fsr[14:12],       // ftt

                                                   //2'b0,                     // qne, rsvd

                                                   lsu_ffu_ld_data_d1[11:0]};   // fcc0, aexc, cexc

   assign t3_fpufsr_data[27:0] = {ctl_dp_fcc_w2[7:2],

                                                    t3_fsr[21:20],  // rnd

                                                    t3_fsr[19:15],  // TEM

                                                    ctl_dp_ftt_w2[2:0],  // ftt

                                                    ctl_dp_fcc_w2[1:0],

                                                    ctl_dp_exc_w2[9:0]};

`ifdef FPGA_SYN_1THREAD

   mux3ds #28 fsr0_mux(.dout (t0_fsr_nxt[27:0]),

                       .in0  (t0_fsr[27:0]),

                       .in1  (t0_ldfsr_data[27:0]),

                       .in2  (t0_fpufsr_data[27:0]),

                       .sel0 (ctl_dp_fsr_sel_old[0]),

                       .sel1 (ctl_dp_fsr_sel_ld[0]),

                       .sel2 (ctl_dp_fsr_sel_fpu[0]));

   // FSR registers

   // need only 28 flops for FSR since rest are always 0

   dffr_s #28 fsr0_reg(.din (t0_fsr_nxt[27:0]),

                                 .q   (t0_fsr[27:0]),

                     .rst(reset),

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

   assign current_fsr[27:0] = t0_fsr[27:0];

`else

   mux3ds #28 fsr0_mux(.dout (t0_fsr_nxt[27:0]),

                       .in0  (t0_fsr[27:0]),

                       .in1  (t0_ldfsr_data[27:0]),

                       .in2  (t0_fpufsr_data[27:0]),

                       .sel0 (ctl_dp_fsr_sel_old[0]),

                       .sel1 (ctl_dp_fsr_sel_ld[0]),

                       .sel2 (ctl_dp_fsr_sel_fpu[0]));

   mux3ds #28 fsr1_mux(.dout (t1_fsr_nxt[27:0]),

                       .in0  (t1_fsr[27:0]),

                       .in1  (t1_ldfsr_data[27:0]),

                       .in2  (t1_fpufsr_data[27:0]),

                       .sel0 (ctl_dp_fsr_sel_old[1]),

                       .sel1 (ctl_dp_fsr_sel_ld[1]),

                       .sel2 (ctl_dp_fsr_sel_fpu[1]));

   mux3ds #28 fsr2_mux(.dout (t2_fsr_nxt[27:0]),

                       .in0  (t2_fsr[27:0]),

                       .in1  (t2_ldfsr_data[27:0]),

                       .in2  (t2_fpufsr_data[27:0]),

                       .sel0 (ctl_dp_fsr_sel_old[2]),

                       .sel1 (ctl_dp_fsr_sel_ld[2]),

                       .sel2 (ctl_dp_fsr_sel_fpu[2]));

   mux3ds #28 fsr3_mux(.dout (t3_fsr_nxt[27:0]),

                       .in0  (t3_fsr[27:0]),

                       .in1  (t3_ldfsr_data[27:0]),

                       .in2  (t3_fpufsr_data[27:0]),

                       .sel0 (ctl_dp_fsr_sel_old[3]),

                       .sel1 (ctl_dp_fsr_sel_ld[3]),

                       .sel2 (ctl_dp_fsr_sel_fpu[3]));

   // FSR registers

   // need only 28 flops for FSR since rest are always 0

   dffr_s #28 fsr0_reg(.din (t0_fsr_nxt[27:0]),

                                 .q   (t0_fsr[27:0]),

                     .rst(reset),

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

   dffr_s #28 fsr1_reg(.din (t1_fsr_nxt[27:0]),

                                 .q   (t1_fsr[27:0]),

                     .rst(reset),

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

   dffr_s #28 fsr2_reg(.din (t2_fsr_nxt[27:0]),

                                 .q   (t2_fsr[27:0]),

                     .rst(reset),

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

   dffr_s #28 fsr3_reg(.din (t3_fsr_nxt[27:0]),

                                 .q   (t3_fsr[27:0]),

                     .rst(reset),

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

   // Current FSR

   mux4ds #28 curr_fsr_mux(.dout (current_fsr[27:0]),

                           .in0  (t0_fsr[27:0]),

                           .in1  (t1_fsr[27:0]),

                           .in2  (t2_fsr[27:0]),

                           .in3  (t3_fsr[27:0]),

                           .sel0 (ctl_dp_fp_thr[0]),

                           .sel1 (ctl_dp_fp_thr[1]),

                           .sel2 (ctl_dp_fp_thr[2]),

                           .sel3 (ctl_dp_fp_thr[3]));

`endif // !`ifdef FPGA_SYN_1THREAD

   assign dp_ctl_fsr_fcc = {current_fsr[27:22], current_fsr[11:10]};

   assign dp_ctl_fsr_rnd = current_fsr[21:20];

   assign dp_ctl_fsr_tem = current_fsr[19:15];

   assign dp_ctl_fsr_aexc = current_fsr[9:5];

   assign dp_ctl_fsr_cexc = current_fsr[4:0];

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

   //           ECC generation and correction

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

   dp_mux2es #(64) ecc_mux(.dout(ecc_data_in[63:0]),

                           .in0(rs2_rd_data[63:0]),

                           .in1({frf_dp_data[70:39], frf_dp_data[31:0]}),

                           .sel(ctl_dp_ecc_sel_frf));

   assign     synd_in_low[6:0] = {7{ctl_dp_ecc_sel_frf}} & frf_dp_data[38:32];

   assign     synd_in_h[6:0] = {7{ctl_dp_ecc_sel_frf}} & frf_dp_data[77:71];

   zzecc_sctag_ecc39 ecccor_low(.din(ecc_data_in[31:0]),

                                .parity(synd_in_low[6:0]),

                                .dout(corr_data_next[31:0]),

                                .pflag(dp_ctl_synd_out_low[6]),

                                .cflag(dp_ctl_synd_out_low[5:0]));

   zzecc_sctag_ecc39 ecccor_high(.din(ecc_data_in[63:32]),

                                .parity(synd_in_h[6:0]),

                                .dout(corr_data_next[63:32]),

                                .pflag(dp_ctl_synd_out_high[6]),

                                .cflag(dp_ctl_synd_out_high[5:0]));

   dff_s #(64) ecc_corr_data(.din(corr_data_next[63:0]), .q(corr_data[63:0]),

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

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

   // GSR Storage

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

   // GSR registers

   // need only 37 flops for GSR since rest are always 0

   // and the align and rnd fields are in the ctl block

`ifdef FPGA_SYN_1THREAD

   dffr_s #37 gsr0_reg(.din (t0_gsr_nxt[36:0]),

                                 .q   (t0_gsr[36:0]),

                     .rst(reset),

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

   assign     t0_gsr_nxt[36:0] = t0_gsr[36:0];

   assign     gsr_e[36:0] = t0_gsr[36:0];

`else

   dffr_s #37 gsr0_reg(.din (t0_gsr_nxt[36:0]),

                                 .q   (t0_gsr[36:0]),

                     .rst(reset),

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

   dffr_s #37 gsr1_reg(.din (t1_gsr_nxt[36:0]),

                                 .q   (t1_gsr[36:0]),

                     .rst(reset),

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

   dffr_s #37 gsr2_reg(.din (t2_gsr_nxt[36:0]),

                                 .q   (t2_gsr[36:0]),

                     .rst(reset),

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

   dffr_s #37 gsr3_reg(.din (t3_gsr_nxt[36:0]),

                                 .q   (t3_gsr[36:0]),

                     .rst(reset),

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

   dp_mux2es #(37) gsr0_mux(.dout(t0_gsr_nxt[36:0]),

                            .in0(t0_gsr[36:0]),

                            .in1(ctl_dp_wsr_data_w2[36:0]),

                            .sel(ctl_dp_gsr_wsr_w2[0]));

   dp_mux2es #(37) gsr1_mux(.dout(t1_gsr_nxt[36:0]),

                            .in0(t1_gsr[36:0]),

                            .in1(ctl_dp_wsr_data_w2[36:0]),

                            .sel(ctl_dp_gsr_wsr_w2[1]));

   dp_mux2es #(37) gsr2_mux(.dout(t2_gsr_nxt[36:0]),

                            .in0(t2_gsr[36:0]),

                            .in1(ctl_dp_wsr_data_w2[36:0]),

                            .sel(ctl_dp_gsr_wsr_w2[2]));

   dp_mux2es #(37) gsr3_mux(.dout(t3_gsr_nxt[36:0]),

                            .in0(t3_gsr[36:0]),

                            .in1(ctl_dp_wsr_data_w2[36:0]),

                            .sel(ctl_dp_gsr_wsr_w2[3]));

   // GSR_E

   mux4ds #37 curr_gsr_mux(.dout (gsr_e[36:0]),

                           .in0  (t0_gsr[36:0]),

                           .in1  (t1_gsr[36:0]),

                           .in2  (t2_gsr[36:0]),

                           .in3  (t3_gsr[36:0]),