src/core/prf.bsv

   1 /*
   2 Copyright (c) 2013, IIT Madras
   3 All rights reserved.
   4
   5 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
   6
   7 *  Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
   8 *  Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
   9 *  Neither the name of IIT Madras  nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
  10
  11 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  12 ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  13 */
  14 package prf;
  15         import defined_types::*;
  16         `include "core_parameters.bsv"
  17         import Vector::*;
  18         interface Ifc_prf_new;
  19                 method ActionValue#(RFType#(`Reg_width)) read_rs1 (Bit#(5) addr, Operand_type rs1type, Bit#(`Reg_width) data);
  20                 method ActionValue#(RFType#(`Reg_width)) read_rs2 (Bit#(5) addr, Operand_type rs2type, Bit#(`Reg_width) data);
  21                 method ActionValue#(RFType#(`Reg_width)) read_rs3 (Bit#(5) addr, Operand_type rs3type, Bit#(`Reg_width) data);
  22                 method ActionValue#(Tuple2#(Bit#(TLog#(`PRFDEPTH)),Bit#(4))) get_index_pid(Bit#(5) addr, Operand_type rdtype);
  23                 method Action update_rd (Bit#(TLog#(`PRFDEPTH)) index, Bit#(4) pid);
  24                 method Action fwd_from_execution (Bit#(`Reg_width) data, Bit#(TLog#(`PRFDEPTH)) index, Bit#(4) pid);
  25                 method Action fwd_from_memory (Bit#(`Reg_width) data, Bit#(TLog#(`PRFDEPTH)) index, Bit#(4) pid);
  26                 method Action flush_all;
  27         endinterface
  28         (*conflict_free="fwd_from_execution,fwd_from_memory"*)
  29         (*conflict_free="fwd_from_execution,update_rd"*)
  30         (*conflict_free="update_rd,fwd_from_memory"*)
  31         (*synthesize*)
  32         module mkprf_new(Ifc_prf_new);
  33                 Reg#(RFType#(`Reg_width)) physical_rf [`PRFDEPTH];
  34                 Reg#(Bit#(4)) pid_rf [`PRFDEPTH];
  35                 Vector#(`PRFDEPTH,Reg#(Tuple2#(Bit#(5),Operand_type))) rd_rf<-replicateM(mkReg(tuple2(0,IntegerRF)));
  36                 Reg#(Bit#(4)) rg_pid_counter<-mkReg(0);
  37                 Reg#(Bit#(TLog#(`PRFDEPTH))) rg_prf_index<-mkReg(0);
  38                 Wire#(Bool) wr_flush<-mkDWire(False);
  39                 for(Integer i=0;i<`PRFDEPTH;i=i+1)begin
  40                         physical_rf[i]<-mkReg(tagged Absent 0);
  41                         pid_rf[i]<-mkReg(0);
  42                 end
  43                 rule flush_all_mapping(wr_flush);
  44                         for(Integer i=0;i<`PRFDEPTH;i=i+1)begin
  45                                 physical_rf[i]<=tagged Absent 0;
  46                                 pid_rf[i]<=0;
  47                                 rd_rf[i]<=tuple2(0,IntegerRF);
  48                         end
  49                 endrule
  50                 method ActionValue#(RFType#(`Reg_width)) read_rs1 (Bit#(5) addr, Operand_type rs1type, Bit#(`Reg_width) data);
  51                         if(rs1type==IntegerRF && addr==0)
  52                                 return tagged Present 0;
  53                         else if(rs1type==IntegerRF `ifdef spfpu || rs1type==FloatingRF `endif ) begin
  54                                 let array_rd=readVReg(rd_rf); // convert the reg-vector to bit#(5)-vector
  55                                 let index=findElem(tuple2(addr,rs1type),array_rd); // find the index of match
  56                                 if(index matches tagged Valid .idx)begin // if match exists
  57                                         `ifdef verbose $display($time,"\tPRF: READ_RS1: valid index: %d",idx); `endif
  58                                         return physical_rf[idx];
  59                                 end
  60                                 else // there is no instruction in pipe updating this reg.
  61                                         return tagged Present data;
  62                         end
  63                                 else // there is no instruction in pipe updating this reg.
  64                                         return tagged Present data;
  65                 endmethod
  66                 method ActionValue#(RFType#(`Reg_width)) read_rs2 (Bit#(5) addr, Operand_type rs2type, Bit#(`Reg_width) data);
  67                         if(rs2type==IntegerRF && addr==0)
  68                                 return tagged Present 0;
  69                         else if(rs2type==IntegerRF `ifdef spfpu || rs2type==FloatingRF `endif ) begin
  70                                 let array_rd=readVReg(rd_rf); // convert the reg-vector to bit#(5)-vector
  71                                 let index=findElem(tuple2(addr,rs2type),array_rd); // find the index of match
  72                                 if(index matches tagged Valid .idx)begin // if match exists
  73                                         `ifdef verbose $display($time,"\tPRF: READ_RS2: valid index: %d",idx); `endif
  74                                         return physical_rf[idx];
  75                                 end
  76                                 else // there is no instruction in pipe updating this reg.
  77                                         return tagged Present data;
  78                         end
  79                                 else // there is no instruction in pipe updating this reg.
  80                                         return tagged Present data;
  81                 endmethod
  82                 method ActionValue#(RFType#(`Reg_width)) read_rs3 (Bit#(5) addr, Operand_type rs3type, Bit#(`Reg_width) data);
  83                         if(rs3type==IntegerRF && addr==0)
  84                                 return tagged Present 0;
  85                         else if(rs3type==IntegerRF `ifdef spfpu || rs3type==FloatingRF `endif ) begin
  86                                 let array_rd=readVReg(rd_rf); // convert the reg-vector to bit#(5)-vector
  87                                 let index=findElem(tuple2(addr,rs3type),array_rd); // find the index of match
  88                                 if(index matches tagged Valid .idx)begin // if match exists
  89                                         return physical_rf[idx];
  90                                 end
  91                                 else // there is no instruction in pipe updating this reg.
  92                                         return tagged Present data;
  93                         end
  94                                 else // there is no instruction in pipe updating this reg.
  95                                         return tagged Present data;
  96                 endmethod
  97                 method ActionValue#(Tuple2#(Bit#(TLog#(`PRFDEPTH)),Bit#(4))) get_index_pid(Bit#(5) addr, Operand_type rdtype);
  98                         let array_rd=readVReg(rd_rf);
  99                         let index=findElem(tuple2(addr,rdtype),array_rd); // find the index of match
 100                         rg_pid_counter<=rg_pid_counter+1;
 101                         if(rg_prf_index==`PRFDEPTH-1)
 102                                 rg_prf_index<=0;
 103                         else
 104                                 rg_prf_index<=rg_prf_index+1;
 105                         rd_rf[rg_prf_index]<=tuple2(addr,rdtype);
 106                         if(index matches tagged Valid .idx)begin
 107                                 if(pack(idx)!=rg_prf_index)
 108                                         rd_rf[idx]<=tuple2(0,IntegerRF);
 109                                 `ifdef verbose $display($time,"\tPRF: Removing previously alotted index: %d",idx); `endif
 110                         end
 111                                 `ifdef verbose $display($time,"\tPRF: Giving Index: %d PID: %d",rg_prf_index, rg_pid_counter); `endif
 112                         return tuple2(rg_prf_index,rg_pid_counter);
 113                 endmethod
 114                 method Action update_rd (Bit#(TLog#(`PRFDEPTH)) index, Bit#(4) pid);
 115                         physical_rf[index]<=tagged Absent pid;
 116                         pid_rf[index]<=pid;
 117                 endmethod
 118                 method Action fwd_from_execution (Bit#(`Reg_width) data, Bit#(TLog#(`PRFDEPTH)) index, Bit#(4) pid);
 119                         `ifdef verbose $display($time,"\tPRF: FWD from EXE Data: %h index: %d pid: %d",data,index,pid); `endif
 120                         physical_rf[index]<=tagged Present data;
 121                 endmethod
 122                 method Action fwd_from_memory (Bit#(`Reg_width) data, Bit#(TLog#(`PRFDEPTH)) index, Bit#(4) pid);
 123                         `ifdef verbose $display($time,"\tPRF: FWD from MEM Data: %h index: %d pid: %d",data,index,pid); `endif
 124                         physical_rf[index]<=tagged Present data;
 125                 endmethod
 126                 method Action flush_all;
 127                         wr_flush<=True;
 128                 endmethod
 129
 130         endmodule
 131 endpackage