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

// 

// OpenSPARC T1 Processor File: sparc_ifu_fdp.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_ifu_fdp

//  Description:

//    The fdp contains the pc's for all four threads and the PC and

//    nPC for all pipestages register.  The fetcher also contains two

//    adders for doing PC + br_offset and PC + 4.

//    The fdp also holds the last fetched icache data for each thread

//    and the next instruction register, which has the top half of the

//    double instruction bundle which is fetched from the icache.

*/

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

// Local header file includes / local defines

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

/*

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

*

* OpenSPARC T1 Processor File: ifu.h

* 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: ifu.h

//  Description:

//  All ifu defines

*/

//--------------------------------------------

// Icache Values in IFU::ICD/ICV/ICT/FDP/IFQDP

//--------------------------------------------

// Set Values

// IC_IDX_HI = log(icache_size/4ways) - 1

// !!IMPORTANT!! a change to IC_LINE_SZ will mean a change to the code as

//   well.  Unfortunately this has not been properly parametrized.

//   Changing the IC_LINE_SZ param alone is *not* enough.

// !!IMPORTANT!! a change to IC_TAG_HI will mean a change to the code as

//   well.  Changing the IC_TAG_HI param alone is *not* enough to

//   change the PA range. 

// highest bit of PA

// Derived Values

// 4095

// number of entries - 1 = 511

// 12

// 28

// 7

// tags for all 4 ways + parity

// 116

// 115

//----------------------------------------------------------------------

// For thread scheduler in IFU::DTU::SWL

//----------------------------------------------------------------------

// thread states:  (thr_state[4:0])

// thread configuration register bit fields

//----------------------------------------------------------------------

// For MIL fsm in IFU::IFQ

//----------------------------------------------------------------------

//---------------------------------------------------

// Interrupt Block

//---------------------------------------------------

//-------------------------------------

// IFQ

//-------------------------------------

// valid bit plus ifill

//`ifdef SPARC_L2_64B

//`else

//`define BANK_ID_HI 8

//`define BANK_ID_LO 7

//`endif

//`define CPX_INV_PA_HI  116

//`define CPX_INV_PA_LO  112

//----------------------------------------

// IFU Traps

//----------------------------------------

// precise

// disrupting

//`define VER_MAXTL      {5'b0, fcl_fdp_hprivmode_e, 2'b10}

//`define VER_IMPL_MASK  24'h002301

//`define VERSION_REG_HPV  {`VER_MANUF, `VER_IMPL_MASK, `VER_MAXGL, 5'b0, fcl_fdp_hprivmode_e, 2'b10, `VER_MAXWIN}

//`define VERSION_REG      {`VER_MANUF, `VER_IMPL_MASK, `VER_MAXGL, 8'h06, `VER_MAXWIN}

//FPGA_SYN enables all FPGA related modifications

module sparc_ifu_fdp(/*AUTOARG*/

   // Outputs

   so, fdp_itlb_ctxt_bf, fdp_icd_vaddr_bf, fdp_icv_index_bf,

   fdp_erb_pc_f, fdp_dtu_inst_s, ifu_exu_pc_d, ifu_exu_rs1_s,

   ifu_exu_rs2_s, ifu_exu_rs3_s, ifu_tlu_pc_m, ifu_tlu_npc_m,

   ifu_tlu_pc_oor_e, ifu_exu_pcver_e, fdp_fcl_swc_s2,

   fdp_fcl_pc_oor_vec_f, fdp_fcl_pc_oor_e, fdp_fcl_op_s,

   fdp_fcl_op3_s, fdp_fcl_ibit_s,

   // Inputs

   rclk, se, si, const_maskid, lsu_t0_pctxt_state,

   lsu_t1_pctxt_state, lsu_t2_pctxt_state, lsu_t3_pctxt_state,

   exu_ifu_brpc_e, tlu_ifu_trappc_w2, tlu_ifu_trapnpc_w2,

   tlu_itlb_dmp_nctxt_g, tlu_itlb_dmp_actxt_g, tlu_itlb_tte_tag_w2,

   dtu_fdp_thrconf_e, icd_fdp_fetdata_s1, icd_fdp_topdata_s1,

   ifq_fdp_fill_inst, fcl_fdp_oddwin_s, fcl_fdp_pcoor_vec_f,

   fcl_fdp_pcoor_f, fcl_fdp_mask32b_f, fcl_fdp_addr_mask_d,

   fcl_fdp_tctxt_sel_prim, fcl_fdp_usenir_sel_nir_s1,

   fcl_fdp_rbinst_sel_inste_s, fcl_fdp_thrtnpc_sel_tnpc_l,

   fcl_fdp_thrtnpc_sel_npcw_l, fcl_fdp_thrtnpc_sel_pcf_l,

   fcl_fdp_thrtnpc_sel_old_l, fcl_fdp_thr_s1_l,

   fcl_fdp_next_thr_bf_l, fcl_fdp_next_ctxt_bf_l, fcl_fdp_thr_s2_l,

   fcl_fdp_nirthr_s1_l, fcl_fdp_tpcbf_sel_pcp4_bf_l,

   fcl_fdp_tpcbf_sel_brpc_bf_l, fcl_fdp_tpcbf_sel_trap_bf_l,

   fcl_fdp_tpcbf_sel_old_bf_l, fcl_fdp_pcbf_sel_swpc_bf_l,

   fcl_fdp_pcbf_sel_nosw_bf_l, fcl_fdp_pcbf_sel_br_bf_l,

   fcl_fdp_trrbpc_sel_trap_bf_l, fcl_fdp_trrbpc_sel_rb_bf_l,

   fcl_fdp_trrbpc_sel_err_bf_l, fcl_fdp_trrbpc_sel_pcs_bf_l,

   fcl_fdp_noswpc_sel_tnpc_l_bf, fcl_fdp_noswpc_sel_old_l_bf,

   fcl_fdp_noswpc_sel_inc_l_bf, fcl_fdp_nextpcs_sel_pce_f_l,

   fcl_fdp_nextpcs_sel_pcd_f_l, fcl_fdp_nextpcs_sel_pcs_f_l,

   fcl_fdp_nextpcs_sel_pcf_f_l, fcl_fdp_rdsr_sel_pc_e_l,

   fcl_fdp_rdsr_sel_ver_e_l, fcl_fdp_rdsr_sel_thr_e_l,

   fcl_fdp_inst_sel_curr_s_l, fcl_fdp_inst_sel_switch_s_l,

   fcl_fdp_inst_sel_nir_s_l, fcl_fdp_inst_sel_nop_s_l,

   fcl_fdp_tinst_sel_curr_s_l, fcl_fdp_tinst_sel_rb_s_l,

   fcl_fdp_tinst_sel_old_s_l, fcl_fdp_tinst_sel_ifq_s_l,

   fcl_fdp_dmpthr_l, fcl_fdp_ctxt_sel_dmp_bf_l,

   fcl_fdp_ctxt_sel_sw_bf_l, fcl_fdp_ctxt_sel_curr_bf_l

   );

   input       rclk,

                     se,

                     si;

   input [7:0] const_maskid;

   input [12:0] lsu_t0_pctxt_state,   // primary context

                            lsu_t1_pctxt_state,

                            lsu_t2_pctxt_state,

                            lsu_t3_pctxt_state;

   //   input    exu_ifu_va_oor_e;

   input [47:0] exu_ifu_brpc_e;        // br address for dir branch

   input [48:0] tlu_ifu_trappc_w2,     // trap/exception PC

                            tlu_ifu_trapnpc_w2;    // next trap PC

   input        tlu_itlb_dmp_nctxt_g,

                            tlu_itlb_dmp_actxt_g;

   input [12:0] tlu_itlb_tte_tag_w2;

//   input [`IC_IDX_HI:4] ifq_fdp_icindex_bf;   // index + 1 bit for 16B write

   input [40:0]         dtu_fdp_thrconf_e;

   input [32:0]         icd_fdp_fetdata_s1,    // 4 inst + 4 sw bits

                                    icd_fdp_topdata_s1;    // next instruction

   input [32:0]         ifq_fdp_fill_inst;    // icache miss return

   input                fcl_fdp_oddwin_s;

   input [3:0]          fcl_fdp_pcoor_vec_f;

   input                fcl_fdp_pcoor_f;

   input                fcl_fdp_mask32b_f;

   input                fcl_fdp_addr_mask_d;

   input [3:0]          fcl_fdp_tctxt_sel_prim;

   // 2:1 mux selects

   input                fcl_fdp_usenir_sel_nir_s1;   // same as usenir_d2

   input [3:0]          fcl_fdp_rbinst_sel_inste_s;  // rollback 1 or 2 

   input [3:0]          fcl_fdp_thrtnpc_sel_tnpc_l,  // load npc

                              fcl_fdp_thrtnpc_sel_npcw_l,

                                    fcl_fdp_thrtnpc_sel_pcf_l,

                              fcl_fdp_thrtnpc_sel_old_l;

   input [3:0]          fcl_fdp_thr_s1_l;            // s2 thr (64*5 muxes)

   // other mux selects

   input [3:0]          fcl_fdp_next_thr_bf_l;  // for thrpc output mux

   input [3:0]          fcl_fdp_next_ctxt_bf_l; // for ctxt output mux

   input [3:0]          fcl_fdp_thr_s2_l;       // s2 thr (64*5 muxes)

   input [3:0]          fcl_fdp_nirthr_s1_l;        // same as thr_s1, but protected

   input [3:0]          fcl_fdp_tpcbf_sel_pcp4_bf_l, // selects for thread PC muxes

                              fcl_fdp_tpcbf_sel_brpc_bf_l,

                              fcl_fdp_tpcbf_sel_trap_bf_l,

                              fcl_fdp_tpcbf_sel_old_bf_l;

   input                fcl_fdp_pcbf_sel_swpc_bf_l,

                              fcl_fdp_pcbf_sel_nosw_bf_l,

                              fcl_fdp_pcbf_sel_br_bf_l;

   input [3:0]          fcl_fdp_trrbpc_sel_trap_bf_l,

                              fcl_fdp_trrbpc_sel_rb_bf_l,

                              fcl_fdp_trrbpc_sel_err_bf_l,

                              fcl_fdp_trrbpc_sel_pcs_bf_l;

   input                fcl_fdp_noswpc_sel_tnpc_l_bf,    // next pc select from trap,

                              fcl_fdp_noswpc_sel_old_l_bf,

                              fcl_fdp_noswpc_sel_inc_l_bf;

   input [3:0]          fcl_fdp_nextpcs_sel_pce_f_l,

                              fcl_fdp_nextpcs_sel_pcd_f_l,

                              fcl_fdp_nextpcs_sel_pcs_f_l,

                              fcl_fdp_nextpcs_sel_pcf_f_l;

   input                fcl_fdp_rdsr_sel_pc_e_l,

                              fcl_fdp_rdsr_sel_ver_e_l,

                              fcl_fdp_rdsr_sel_thr_e_l;

   input                fcl_fdp_inst_sel_curr_s_l,       // selects for inst_s2

                              fcl_fdp_inst_sel_switch_s_l,

                              fcl_fdp_inst_sel_nir_s_l,

                              fcl_fdp_inst_sel_nop_s_l;

   input [3:0]          fcl_fdp_tinst_sel_curr_s_l, // selects for tinst regs

                              fcl_fdp_tinst_sel_rb_s_l,

                              fcl_fdp_tinst_sel_old_s_l,

                              fcl_fdp_tinst_sel_ifq_s_l;

   input [3:0]          fcl_fdp_dmpthr_l;

   input                fcl_fdp_ctxt_sel_dmp_bf_l,

                              fcl_fdp_ctxt_sel_sw_bf_l,

                              fcl_fdp_ctxt_sel_curr_bf_l;

   output               so;

   output [12:0]        fdp_itlb_ctxt_bf;

   output [47:2]        fdp_icd_vaddr_bf;   // 11:2 is index to ic

   output [11:5]        fdp_icv_index_bf;

   output [47:0]        fdp_erb_pc_f;

   output [31:0]        fdp_dtu_inst_s;     // 32b inst + switch bit 

   output [47:0]        ifu_exu_pc_d;       // PC for rel branch

   output [4:0]         ifu_exu_rs1_s,      // reg file read address

                                    ifu_exu_rs2_s,

                                    ifu_exu_rs3_s;

   output [48:0]        ifu_tlu_pc_m,

                                    ifu_tlu_npc_m;

   output               ifu_tlu_pc_oor_e;

   output [63:0]        ifu_exu_pcver_e;    // PCs to different dests.

   output               fdp_fcl_swc_s2;       // tells whether to switch or not

   output [3:0]         fdp_fcl_pc_oor_vec_f; // PC va hole check

   output               fdp_fcl_pc_oor_e;

   output [1:0]         fdp_fcl_op_s;

   output [5:2]         fdp_fcl_op3_s;

   output               fdp_fcl_ibit_s;

//----------------------------------------------------------------------

// Declarations

//----------------------------------------------------------------------

   // local signals

   // Contexts

   wire [12:0]   curr_ctxt,

                            sw_ctxt,

                            dmp_ctxt,

                            dmp_ctxt_unq,

                            dmp_ctxt1,

                            dmp_ctxt2,

                            t0_ctxt_bf,

                            t1_ctxt_bf,

                            t2_ctxt_bf,

                            t3_ctxt_bf;

   // PCs

   wire [48:0]  t0pc_f, t1pc_f, t2pc_f, t3pc_f,         // F stage thread PC

                            t0pc_s, t1pc_s, t2pc_s, t3pc_s,         // S stage thr pc

                            t0_next_pcs_f, t1_next_pcs_f, t2_next_pcs_f, t3_next_pcs_f,

                            t0npc_bf, t1npc_bf, t2npc_bf, t3npc_bf, // Next PC in

                                                                                                  // BF stage

                            pc_s, pc_d, pc_e, pc_m, pc_w,

                            npc_s, npc_d, npc_e, npc_m, npc_w,

                            pc_d_adj, npc_d_adj;

   wire [47:0]  pc_bf,

                            swpc_bf,                // PC of next thread if not branch

                pc_f;

   wire [48:0]  nextpc_nosw_bf,         // next pc if no switch

                            am_mask;

   // trap PCs and rollback PCs

   wire [48:0]  t0_trap_rb_pc_bf,

                            t1_trap_rb_pc_bf,

                            t2_trap_rb_pc_bf,

                            t3_trap_rb_pc_bf;

   wire [48:0]  thr_trappc_bf,

                            t0_trapnpc_f,

                            t1_trapnpc_f,

                            t2_trapnpc_f,

                            t3_trapnpc_f,

                            trapnpc0_bf,

                            trapnpc1_bf,

                            trapnpc2_bf,

                            trapnpc3_bf;

   // Branch PCs

   wire [48:0]  pcinc_f;                // incr output

   // Instruction Words

   wire [32:0]  inst_s2,                // instruction to switch to in S

                            fdp_inst_s,             // instruction to be sent to D

                            t0inst_s1,              // input to thr inst reg in S

                            t1inst_s1,

                            t2inst_s1,

                            t3inst_s1,

                            t0inst_s2,              // thr inst reg output

                            t1inst_s2,

                            t2inst_s2,

                            t3inst_s2;

   wire [32:0]  inst_s1;                // fetched instruction in S

   wire [32:0]  inst_s1_bf1;            // buf version of inst_s1

   wire [32:0]  rb_inst0_s,             // instruction to rollback to

                            rb_inst1_s,             // instruction to rollback to

                            rb_inst2_s,             // instruction to rollback to

                            rb_inst3_s,             // instruction to rollback to

                            inst_d,                 //   rollback 1

                            inst_e;                 //   rollback 2

   // Next instruction word

   wire [32:0]  nirdata_s1,             // next inst reg contents

                            t0nir,                  // thread NIR reg output

                            t1nir,

                            t2nir,

                            t3nir;

   wire         clk;

   //

   // Code start here 

   //

   assign       clk = rclk;

//----------------------------------------------------------------------

// Context Reg

//----------------------------------------------------------------------

   assign t0_ctxt_bf = lsu_t0_pctxt_state & {13{fcl_fdp_tctxt_sel_prim[0]}};

   assign t1_ctxt_bf = lsu_t1_pctxt_state & {13{fcl_fdp_tctxt_sel_prim[1]}};

   assign t2_ctxt_bf = lsu_t2_pctxt_state & {13{fcl_fdp_tctxt_sel_prim[2]}};

   assign t3_ctxt_bf = lsu_t3_pctxt_state & {13{fcl_fdp_tctxt_sel_prim[3]}};

   dp_mux4ds #(13) sw_ctxt_mux(.dout (sw_ctxt),

                               .in0  (t0_ctxt_bf),

                               .in1  (t1_ctxt_bf),

                               .in2  (t2_ctxt_bf),

                               .in3  (t3_ctxt_bf),

                               .sel0_l (fcl_fdp_next_ctxt_bf_l[0]),

                               .sel1_l (fcl_fdp_next_ctxt_bf_l[1]),

                               .sel2_l (fcl_fdp_next_ctxt_bf_l[2]),

                               .sel3_l (fcl_fdp_next_ctxt_bf_l[3]));

   dp_mux4ds #(13) curr_ctxt_mux(.dout (curr_ctxt),

                             .in0  (t0_ctxt_bf),

                             .in1  (t1_ctxt_bf),

                             .in2  (t2_ctxt_bf),

                             .in3  (t3_ctxt_bf),

                             .sel0_l (fcl_fdp_thr_s2_l[0]),

                             .sel1_l (fcl_fdp_thr_s2_l[1]),

                             .sel2_l (fcl_fdp_thr_s2_l[2]),

                             .sel3_l (fcl_fdp_thr_s2_l[3]));

   dp_mux4ds #(13) dmp_ctxt_mux(.dout (dmp_ctxt_unq),

                              .in0  (lsu_t0_pctxt_state),

                              .in1  (lsu_t1_pctxt_state),

                              .in2  (lsu_t2_pctxt_state),

                              .in3  (lsu_t3_pctxt_state),

                              .sel0_l (fcl_fdp_dmpthr_l[0]),

                              .sel1_l (fcl_fdp_dmpthr_l[1]),

                              .sel2_l (fcl_fdp_dmpthr_l[2]),

                              .sel3_l (fcl_fdp_dmpthr_l[3]));

 // !`ifdef FPGA_SYN_1THREAD

   assign dmp_ctxt1 = dmp_ctxt_unq & {13{~(tlu_itlb_dmp_nctxt_g |

                                                                         tlu_itlb_dmp_actxt_g)}};

//`ifdef SPARC_HPV_EN   

   assign dmp_ctxt2 = {tlu_itlb_tte_tag_w2[12:7],tlu_itlb_tte_tag_w2[6:0]} &

                            {13{tlu_itlb_dmp_actxt_g}};

//`else

//  assign dmp_ctxt2 = {tlu_itlb_tte_tag_w2[13:8],tlu_itlb_tte_tag_w2[6:0]} & 

//                          {13{tlu_itlb_dmp_actxt_g}};

//`endif   

   assign dmp_ctxt = dmp_ctxt1 | dmp_ctxt2;

   dp_mux3ds #(13) ctxt_mux (.dout (fdp_itlb_ctxt_bf),

                                             .in0  (curr_ctxt),

                                             .in1  (sw_ctxt),

                                             .in2  (dmp_ctxt),

                                             .sel0_l  (fcl_fdp_ctxt_sel_curr_bf_l),

                                             .sel1_l  (fcl_fdp_ctxt_sel_sw_bf_l),

                                             .sel2_l  (fcl_fdp_ctxt_sel_dmp_bf_l));

// ----------------------------------------------------------------------

// PC datapath    

// ----------------------------------------------------------------------

   // pc/thr to exu for rdsr instruction

   // this is the only 64 bit cell in the IFU

   dp_mux3ds #(64) ver_mux(.dout (ifu_exu_pcver_e[63:0]),

                                           .in0  ({{16{pc_e[47]}}, pc_e[47:0]}),

                                           .in1  ({16'h003e,

                                 16'h0023,

                                 const_maskid[7:0],

                                 8'h03,

                                 8'h06,

                                 8'h07}),

                                           .in2  ({12'b0,

                                 dtu_fdp_thrconf_e[40:29],

                                 4'b0,

                                 dtu_fdp_thrconf_e[28:9],

                                 2'b0,

                                 dtu_fdp_thrconf_e[8:3],

                                 5'b0,

                                 dtu_fdp_thrconf_e[2:0]}),

                                           .sel0_l  (fcl_fdp_rdsr_sel_pc_e_l),

                                           .sel1_l  (fcl_fdp_rdsr_sel_ver_e_l),

                                           .sel2_l  (fcl_fdp_rdsr_sel_thr_e_l));

   // Select the next thread pc (for F stage)

   dp_mux4ds #(49) t0_pcbf_mux(.dout (t0npc_bf),

                                               .in0 ({fcl_fdp_pcoor_vec_f[0], t0pc_f[47:0]}),

                                               .in1 (nextpc_nosw_bf),

                                               .in2 (t0_trap_rb_pc_bf),

                                               .in3 ({1'b0, exu_ifu_brpc_e}),

                                               .sel0_l (fcl_fdp_tpcbf_sel_old_bf_l[0]),

                                               .sel1_l (fcl_fdp_tpcbf_sel_pcp4_bf_l[0]),

                                               .sel2_l (fcl_fdp_tpcbf_sel_trap_bf_l[0]),

                                               .sel3_l (fcl_fdp_tpcbf_sel_brpc_bf_l[0]));

   dp_mux4ds #(49) t1_pcbf_mux(.dout (t1npc_bf),

                                               .in0 ({fcl_fdp_pcoor_vec_f[1], t1pc_f[47:0]}),

                                               .in1 (nextpc_nosw_bf),

                                               .in2 (t1_trap_rb_pc_bf),

                                               .in3 ({1'b0, exu_ifu_brpc_e}),

                                               .sel0_l (fcl_fdp_tpcbf_sel_old_bf_l[1]),

                                               .sel1_l (fcl_fdp_tpcbf_sel_pcp4_bf_l[1]),

                                               .sel2_l (fcl_fdp_tpcbf_sel_trap_bf_l[1]),

                                               .sel3_l (fcl_fdp_tpcbf_sel_brpc_bf_l[1]));

   dp_mux4ds #(49) t2_pcbf_mux(.dout (t2npc_bf),

                                               .in0 ({fcl_fdp_pcoor_vec_f[2], t2pc_f[47:0]}),

                                               .in1 (nextpc_nosw_bf),

                                               .in2 (t2_trap_rb_pc_bf),

                                               .in3 ({1'b0, exu_ifu_brpc_e}),

                                               .sel0_l (fcl_fdp_tpcbf_sel_old_bf_l[2]),

                                               .sel1_l (fcl_fdp_tpcbf_sel_pcp4_bf_l[2]),

                                               .sel2_l (fcl_fdp_tpcbf_sel_trap_bf_l[2]),

                                               .sel3_l (fcl_fdp_tpcbf_sel_brpc_bf_l[2]));

   dp_mux4ds #(49) t3_pcbf_mux(.dout (t3npc_bf),

                                               .in0 ({fcl_fdp_pcoor_vec_f[3], t3pc_f[47:0]}),

                                               .in1 (nextpc_nosw_bf),

                                               .in2 (t3_trap_rb_pc_bf),

                                               .in3 ({1'b0, exu_ifu_brpc_e}),

                                               .sel0_l (fcl_fdp_tpcbf_sel_old_bf_l[3]),

                                               .sel1_l (fcl_fdp_tpcbf_sel_pcp4_bf_l[3]),

                                               .sel2_l (fcl_fdp_tpcbf_sel_trap_bf_l[3]),

                                               .sel3_l (fcl_fdp_tpcbf_sel_brpc_bf_l[3]));

   // F stage thread PC regs;  use low power thr flop

   dff  #(49)  t0_pcf_reg(.din (t0npc_bf),

                                          .clk (clk),

                                          .q   (t0pc_f),

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

   dff  #(49)  t1_pcf_reg(.din (t1npc_bf),

                                          .clk (clk),

                                          .q   (t1pc_f),

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

   dff  #(49)  t2_pcf_reg(.din (t2npc_bf),

                                          .clk (clk),

                                          .q   (t2pc_f),

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

   dff  #(49)  t3_pcf_reg(.din (t3npc_bf),

                                          .clk (clk),

                                          .q   (t3pc_f),

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

   assign fdp_fcl_pc_oor_vec_f = {t3pc_f[48], t2pc_f[48],

                                                          t1pc_f[48], t0pc_f[48]};

   // select the pc to be used on a switch -- need to protect

   dp_mux4ds #(48) swpc_mux(.dout (swpc_bf),

                                            .in0 (t0pc_f[47:0]),

                                            .in1 (t1pc_f[47:0]),

                                            .in2 (t2pc_f[47:0]),

                                            .in3 (t3pc_f[47:0]),

                                            .sel0_l (fcl_fdp_next_thr_bf_l[0]),

                                            .sel1_l (fcl_fdp_next_thr_bf_l[1]),

                                            .sel2_l (fcl_fdp_next_thr_bf_l[2]),

                                            .sel3_l (fcl_fdp_next_thr_bf_l[3]));

   // choose between I$ write address and read address

   // need mux only for lower 11 bits (2+3 + ICINDEX_SIZE)

//   dp_mux2es #(48) ifqfdp_mux(.dout (icaddr_nosw_bf[47:0]),

//           .in0  (nextpc_nosw_bf[47:0]), 

//           .in1  ({{37{1'b0}}, ifq_fdp_icindex_bf, 4'b0}),

//           .sel  (fcl_fdp_ifqfdp_sel_ifq_bf));  // 1=ifq

   // implements switch and branch

   // can we cut this down to 11 bits? No! tlb needs all 48

//   dp_mux4ds #(48) nxt_icaddr_mux(.dout  (icaddr_bf),

//                                                      .in0   (swpc_bf[47:0]), 

//                                                      .in1   (nextpc_nosw_bf[47:0]),

//                                                      .in2   ({8'b0, {`IC_TAG_SZ{1'b0}}, 

//                                         ifq_fdp_icindex_bf, 4'b0}),

//                                                      .in3   (exu_ifu_brpc_e[47:0]), 

//                                                      .sel0_l (fcl_fdp_icaddr_sel_swpc_bf_l),

//                                                      .sel1_l (fcl_fdp_icaddr_sel_curr_bf_l),

//                                                      .sel2_l (fcl_fdp_icaddr_sel_ifq_bf_l),

//                                                      .sel3_l (fcl_fdp_icaddr_sel_br_bf_l));

//   assign fdp_icd_vaddr_bf = icaddr_bf[47:0];

   // this goes to the itlb, icd and ict on top of fdp

   // this is !!very critical!!

   assign fdp_icd_vaddr_bf = pc_bf[47:2];

   // create separate output for the icv to the left

   assign fdp_icv_index_bf = pc_bf[11:5];

   // Place this mux as close to the top (itlb) as possible

   dp_mux3ds #(48) pcbf_mux(.dout  (pc_bf[47:0]),

                          .in0   (swpc_bf[47:0]),

                          .in1   (nextpc_nosw_bf[47:0]),

                          .in2   (exu_ifu_brpc_e[47:0]),

                          .sel0_l (fcl_fdp_pcbf_sel_swpc_bf_l),

                          .sel1_l (fcl_fdp_pcbf_sel_nosw_bf_l),

                          .sel2_l (fcl_fdp_pcbf_sel_br_bf_l));