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

// 

// OpenSPARC T1 Processor File: sparc_ifu_imd.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_imd

//  Description:

//  Contains the immediate operand datapath.  Has two outputs:  The

//  simm data to the EXU and the branch offset to the IFU.

*/

module sparc_ifu_imd(/*AUTOARG*/

   // Outputs

   ifu_exu_imm_data_d, dtu_inst_d, ifu_exu_rd_d, ifu_lsu_rd_e,

   ifu_lsu_imm_asi_d, ifu_tlu_imm_asi_d, ifu_lsu_imm_asi_vld_d, ifu_tlu_sraddr_d,

   ifu_tlu_sraddr_d_v2, imd_dcl_brcond_d, imd_dcl_mvcond_d,

   imd_dcl_abit_d, so, ifu_ffu_frs1_d, ifu_ffu_frs2_d, ifu_ffu_frd_d,

   ifu_ffu_fpopcode_d, ifu_ffu_fcc_num_d,

   // Inputs

   rclk, se, si, fdp_dtu_inst_s, fcl_imd_oddwin_d,

   dcl_imd_immdata_sel_simm13_d_l, dcl_imd_immdata_sel_movcc_d_l,

   dcl_imd_immdata_sel_sethi_d_l, dcl_imd_immdata_sel_movr_d_l,

   dcl_imd_broff_sel_call_d_l, dcl_imd_broff_sel_br_d_l,

   dcl_imd_broff_sel_bcc_d_l, dcl_imd_broff_sel_bpcc_d_l,

   dcl_imd_immbr_sel_br_d, dcl_imd_call_inst_d

   );

   input rclk,

         se,

         si;

   input [31:0] fdp_dtu_inst_s;          // instruction from fetch

   input        fcl_imd_oddwin_d;       // are we in an even or odd window

   input        dcl_imd_immdata_sel_simm13_d_l,  // imm data selects

                            dcl_imd_immdata_sel_movcc_d_l,

                            dcl_imd_immdata_sel_sethi_d_l,

                            dcl_imd_immdata_sel_movr_d_l;

   input        dcl_imd_broff_sel_call_d_l,      // dir branch offset select

                            dcl_imd_broff_sel_br_d_l,

                            dcl_imd_broff_sel_bcc_d_l,

                            dcl_imd_broff_sel_bpcc_d_l;

   input        dcl_imd_immbr_sel_br_d;  // use branch offset or simm data

   input        dcl_imd_call_inst_d;

   output [31:0] ifu_exu_imm_data_d;      // imm data to EXU

   output [31:0] dtu_inst_d;              // D stage inst to DEC

   output [4:0]  ifu_exu_rd_d,

                             ifu_lsu_rd_e;

   output [7:0]  ifu_lsu_imm_asi_d;       // ASI for ldA and stA

   output [8:0]  ifu_tlu_imm_asi_d;       // ASI for ldA and stA

   output        ifu_lsu_imm_asi_vld_d;

   output [6:0]  ifu_tlu_sraddr_d;

   output [6:0]  ifu_tlu_sraddr_d_v2;

   output [3:0]  imd_dcl_brcond_d;

   output [7:0]  imd_dcl_mvcond_d;

   output        imd_dcl_abit_d;         // anull bit for cond branch

   output        so;

   output [4:0]  ifu_ffu_frs1_d,

                             ifu_ffu_frs2_d,

                             ifu_ffu_frd_d;

   output [8:0]  ifu_ffu_fpopcode_d;

   output [1:0]  ifu_ffu_fcc_num_d;

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

// Declaration of local signals

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

   wire [4:0]  sraddr5;

   wire [31:0] imm_data_d;       // imm data 

   wire [31:0] dtu_inst_d,

                           simm13,

                           simm11,

                           simm10,

                           imm22,

                           dbr16,

                           dbcc22_nopred,

                           dbcc19_pred,

                           dcall,

                           broffset_d;

   wire        clk, ifu_lsu_imm_asi_vld_f;

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

// Code starts here 

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

   assign      clk = rclk;

   //--------

   // S Stage

   // Contains mostly random logic to help with decode in D stage

   //--------

   // Regfile operations:

   // REMOVED

//   assign ifu_exu_rs1_s = fdp_dtu_inst_s[18:14] ^ 

//                        {{fdp_dtu_inst_s[17] & dcl_imd_oddwin_s},  4'b0000};

//   assign ifu_exu_rs2_s = fdp_dtu_inst_s[4:0] ^ 

//                        {{fdp_dtu_inst_s[3] & dcl_imd_oddwin_s},  4'b0000};

//   assign ifu_exu_rs3_s = fdp_dtu_inst_s[29:25] ^ 

//                        {{fdp_dtu_inst_s[28] & dcl_imd_oddwin_s},  4'b0000};

//   assign imd_dcl_op_s = fdp_dtu_inst_s[31:30];

//   assign imd_dcl_op3_s = fdp_dtu_inst_s[24:19];

   //--------

   // D stage

   // Contains the immediate data and branch offset muxes

   //--------

   dff_s #(32) inst_d_reg(.din  (fdp_dtu_inst_s),

                      .clk  (clk),

                      .q    (dtu_inst_d),

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

   dff_s #(1) ifu_lsu_imm_asi_inst(.din  (fdp_dtu_inst_s[13]),

                      .clk  (clk),

                      .q    (ifu_lsu_imm_asi_vld_f),

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

   assign imd_dcl_abit_d = dtu_inst_d[29];

   // imm data select

   // sext12:0 -- add/sub/and/or/xor/taggedOP/jmpl/ld/store/atomic/div/mul/popc

   //             prefetch/return/restore/save/sir/wr/shft/flush

   //  !!!CAS does not use Imm data!!!

   //

   // sext10:0 -- movcc

   // sext9:0  -- movr

   // 21:0,10'b0 -- sethi

   assign simm13 = {{19{dtu_inst_d[12]}},dtu_inst_d[12:0]};

   assign simm11 = {{21{dtu_inst_d[10]}},dtu_inst_d[10:0]};

   assign simm10 = {{22{dtu_inst_d[9]}},dtu_inst_d[9:0]};

   assign imm22  = {dtu_inst_d[21:0], 10'b0};

   dp_mux4ds  #(32) immdata_mux(.dout (imm_data_d),

                          .in0  (simm13),

                          .in1  (simm11),

                          .in2  (simm10),

                          .in3  (imm22),

                          .sel0_l (dcl_imd_immdata_sel_simm13_d_l),

                          .sel1_l (dcl_imd_immdata_sel_movcc_d_l),

                          .sel2_l (dcl_imd_immdata_sel_movr_d_l),

                          .sel3_l (dcl_imd_immdata_sel_sethi_d_l));

   // branch offset select

   assign dbr16 = {{14{dtu_inst_d[21]}}, dtu_inst_d[21:20],

                   dtu_inst_d[13:0], 2'b0};

   assign dbcc22_nopred = {{8{dtu_inst_d[21]}}, dtu_inst_d[21:0], 2'b0};

   assign dbcc19_pred = {{11{dtu_inst_d[18]}}, dtu_inst_d[18:0], 2'b0};

   assign dcall = {dtu_inst_d[29:0], 2'b0};

   dp_mux4ds  #(32) broffset_mux(.dout   (broffset_d[31:0]),

                           .in0    (dcall[31:0]),          // call

                           .in1    (dbr16[31:0]),          // br on reg

                           .in2    (dbcc22_nopred[31:0]),  // branch w/o pred

                           .in3    (dbcc19_pred[31:0]),    // branch w/ pred

                           .sel0_l (dcl_imd_broff_sel_call_d_l),

                           .sel1_l (dcl_imd_broff_sel_br_d_l),

                           .sel2_l (dcl_imd_broff_sel_bcc_d_l),

                           .sel3_l (dcl_imd_broff_sel_bpcc_d_l));

   dp_mux2es #(32) immbr_mux(.dout (ifu_exu_imm_data_d[31:0]),

                           .in0  (imm_data_d[31:0]),

                           .in1  (broffset_d[31:0]),

                           .sel  (dcl_imd_immbr_sel_br_d));

   // branch/move condition to dcl

   assign imd_dcl_brcond_d = dtu_inst_d[28:25];

   assign imd_dcl_mvcond_d = dtu_inst_d[17:10];

   // if call instruction set rd = 0f (15)

   assign ifu_exu_rd_d[3:0] = dtu_inst_d[28:25] | {4{dcl_imd_call_inst_d}};

   assign ifu_exu_rd_d[4] = (dtu_inst_d[29] & ~dcl_imd_call_inst_d) ^

                              (ifu_exu_rd_d[3] & fcl_imd_oddwin_d);

   dff_s #(5) rde_ff(.din (ifu_exu_rd_d[4:0]),

                 .clk (clk),

                 .q   (ifu_lsu_rd_e[4:0]),

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

   // read/write pr and read/write sr

   dp_mux2es #(5)  sraddr_mux(.dout (sraddr5[4:0]),

                            .in0  (dtu_inst_d[18:14]),  // rs1 for rdpr

                            .in1  (dtu_inst_d[29:25]),  // rd  for wrpr

                            .sel  (dtu_inst_d[23]));

   assign ifu_tlu_sraddr_d = {dtu_inst_d[19],                     // hpriv

                              {dtu_inst_d[20] & ~dtu_inst_d[19]}, // priv

                              sraddr5[4:0]};

   assign ifu_tlu_sraddr_d_v2 = ifu_tlu_sraddr_d;

   // asi fields for stA, ldA

   // same as fpopcode_d

   assign ifu_lsu_imm_asi_d[7:0] = dtu_inst_d[12:5];

   assign ifu_tlu_imm_asi_d[8:0] = dtu_inst_d[13:5];

   assign ifu_lsu_imm_asi_vld_d = ~ifu_lsu_imm_asi_vld_f;

   // fp reg fields

   assign ifu_ffu_frd_d = dtu_inst_d[29:25];

   assign ifu_ffu_fcc_num_d = dtu_inst_d[26:25];

   assign ifu_ffu_frs1_d = dtu_inst_d[18:14];

   assign ifu_ffu_fpopcode_d = dtu_inst_d[13:5];

   assign ifu_ffu_frs2_d = dtu_inst_d[4:0];

endmodule // sparc_ifu_imd