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Moved writeback pipeline registers from datapth into DMEM and CSR

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This commit is contained in:
David Harris 2021-02-02 13:02:31 -05:00
parent 9d7e242596
commit aad1d3d7dd
7 changed files with 24 additions and 19 deletions
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12
wally-pipelined/src/dmem/dmem.sv
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@ -29,21 +29,25 @@
module dmem (
input logic clk, reset,
input logic FlushW,
//
input logic [1:0] MemRWM,
output logic [1:0] MemRWdcuoutM,
output logic DataMisalignedM,
input logic [`XLEN-1:0] DataAdrM,
input logic [2:0] Funct3M,
/* output logic [`XLEN-1:0] ReadDataM,
input logic [`XLEN-1:0] WriteDataM, */
input logic [2:0] Funct3M,
input logic [`XLEN-1:0] ReadDataM,
output logic [`XLEN-1:0] ReadDataW,
/* input logic [`XLEN-1:0] WriteDataM, */
// faults
input logic DataAccessFaultM,
output logic LoadMisalignedFaultM, LoadAccessFaultM,
output logic StoreMisalignedFaultM, StoreAccessFaultM
);
// Pipeline register
floprc #(`XLEN) ReadDataWReg(clk, reset, FlushW, ReadDataM, ReadDataW);
// Determine if an Unaligned access is taking place
always_comb

2
wally-pipelined/src/ieu/controller.sv
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@ -82,6 +82,8 @@ module controller(
// Main Instruction Decoder
// *** decoding of non-IEU instructions should also go here, and should be gated by MISA bits in a generate so
// they don't get generated if that mode is disabled
always_comb
case(OpD)
// RegWrite_ImmSrc_ALUSrc_MemRW_ResultSrc_Branch_ALUOp_Jump_TargetSrc_W64_CSRWrite_Privileged_Illegal

10
wally-pipelined/src/ieu/datapath.sv
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@ -44,8 +44,8 @@ module datapath (
// Memory stage signals
input logic FlushM,
input logic [2:0] Funct3M,
input logic [`XLEN-1:0] CSRReadValM,
input logic [`XLEN-1:0] ReadDataM,
input logic [`XLEN-1:0] CSRReadValW,
input logic [`XLEN-1:0] ReadDataW,
input logic RetM, TrapM,
output logic [`XLEN-1:0] SrcAM,
output logic [`XLEN-1:0] WriteDataM, DataAdrM,
@ -75,8 +75,6 @@ module datapath (
logic [`XLEN-1:0] ALUResultM;
// Writeback stage signals
logic [`XLEN-1:0] ALUResultW;
logic [`XLEN-1:0] ReadDataW;
logic [`XLEN-1:0] CSRValW;
logic [`XLEN-1:0] ResultW;
assign Rs1D = InstrD[19:15];
@ -111,9 +109,7 @@ module datapath (
// Writeback stage pipeline register and logic
floprc #(`XLEN) ALUResultWReg(clk, reset, FlushW, ALUResultM, ALUResultW);
floprc #(`XLEN) ReadDataWReg(clk, reset, FlushW, ReadDataM, ReadDataW);
floprc #(`XLEN) CSRValWReg(clk, reset, FlushW, CSRReadValM, CSRValW);
floprc #(5) RdWEg(clk, reset, FlushW, RdM, RdW);
mux4 #(`XLEN) resultmux(ALUResultW, ReadDataW, PCLinkW, CSRValW, ResultSrcW, ResultW);
mux4 #(`XLEN) resultmux(ALUResultW, ReadDataW, PCLinkW, CSRReadValW, ResultSrcW, ResultW);
endmodule

4
wally-pipelined/src/ieu/ieu.sv
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@ -35,15 +35,15 @@ module ieu (
input logic [`XLEN-1:0] PCE,
output logic [`XLEN-1:0] PCTargetE,
// Memory stage interface
input logic [`XLEN-1:0] ReadDataM,
input logic DataMisalignedM,
input logic DataAccessFaultM,
input logic [`XLEN-1:0] CSRReadValM,
output logic [1:0] MemRWM,
output logic [`XLEN-1:0] DataAdrM, WriteDataM,
output logic [`XLEN-1:0] SrcAM,
output logic [2:0] Funct3M,
// Writeback stage
input logic [`XLEN-1:0] ReadDataW,
input logic [`XLEN-1:0] CSRReadValW,
input logic [`XLEN-1:0] PCLinkW,
output logic InstrValidW,
// hazards

6
wally-pipelined/src/privileged/csr.sv
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@ -28,6 +28,7 @@
module csr (
input logic clk, reset,
input logic FlushW,
input logic [31:0] InstrM,
input logic [`XLEN-1:0] PCM, SrcAM,
input logic CSRWriteM, TrapM, MTrapM, STrapM, UTrapM, mretM, sretM, uretM,
@ -44,11 +45,11 @@ module csr (
input logic [4:0] SetFflagsM,
output logic [2:0] FRM_REGW,
// output logic [11:0] MIP_REGW, SIP_REGW, UIP_REGW, MIE_REGW, SIE_REGW, UIE_REGW,
output logic [`XLEN-1:0] CSRReadValM,
output logic [`XLEN-1:0] CSRReadValW,
output logic IllegalCSRAccessM
);
logic [`XLEN-1:0] CSRMReadValM, CSRSReadValM, CSRUReadValM, CSRNReadValM, CSRCReadValM;
logic [`XLEN-1:0] CSRMReadValM, CSRSReadValM, CSRUReadValM, CSRNReadValM, CSRCReadValM, CSRReadValM;
logic [`XLEN-1:0] CSRSrcM, CSRRWM, CSRRSM, CSRRCM, CSRWriteValM;
logic [`XLEN-1:0] MSTATUS_REGW, SSTATUS_REGW, USTATUS_REGW;
@ -101,6 +102,7 @@ module csr (
// merge CSR Reads
assign CSRReadValM = CSRUReadValM | CSRSReadValM | CSRMReadValM | CSRCReadValM | CSRNReadValM;
floprc #(`XLEN) CSRValWReg(clk, reset, FlushW, CSRReadValM, CSRReadValW);
// merge illegal accesses: illegal if none of the CSR addresses is legal or privilege is insufficient
assign InsufficientCSRPrivilegeM = (CSRAdrM[9:8] == 2'b11 && PrivilegeModeW != `M_MODE) ||

3
wally-pipelined/src/privileged/privileged.sv
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@ -28,11 +28,12 @@
module privileged (
input logic clk, reset,
input logic FlushW,
input logic CSRWriteM,
input logic [`XLEN-1:0] SrcAM,
input logic [31:0] InstrM,
input logic [`XLEN-1:0] PCM,
output logic [`XLEN-1:0] CSRReadValM,
output logic [`XLEN-1:0] CSRReadValW,
output logic [`XLEN-1:0] PrivilegedNextPCM,
output logic RetM, TrapM,
input logic InstrValidW, FloatRegWriteW, LoadStallD,

6
wally-pipelined/src/wally/wallypipelinedhart.sv
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@ -59,7 +59,7 @@ module wallypipelinedhart (
logic [31:0] InstrD, InstrM;
logic [`XLEN-1:0] PCE, PCM, PCLinkW;
logic [`XLEN-1:0] PCTargetE;
logic [`XLEN-1:0] CSRReadValM;
logic [`XLEN-1:0] CSRReadValW;
logic [`XLEN-1:0] PrivilegedNextPCM;
logic [1:0] MemRWM;
logic InstrValidW;
@ -83,11 +83,11 @@ module wallypipelinedhart (
logic [2:0] FRM_REGW;
logic FloatRegWriteW;
// bus interface to dcu
// bus interface to dmem
logic [1:0] MemRWdcuoutM;
logic [2:0] Funct3M;
logic [`XLEN-1:0] DataAdrM, WriteDataM;
logic [`XLEN-1:0] ReadDataM;
logic [`XLEN-1:0] ReadDataM, ReadDataW;
logic DataStall, InstrStall;
ifu ifu(.*); // instruction fetch unit: PC, branch prediction, instruction cache