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Spill only occurs on 32-bit instructions.

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This commit is contained in:
Ross Thompson 2022-12-30 12:41:25 -06:00
parent 6ac7adbfc4
commit 190f03e15c
1 changed files with 7 additions and 6 deletions
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13
pipelined/src/ifu/spillsupport.sv
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@ -53,9 +53,9 @@ module spillsupport #(parameter CACHE_ENABLED)
localparam integer SPILLTHRESHOLD = CACHE_ENABLED ? `ICACHE_LINELENINBITS/32 : 1; localparam integer SPILLTHRESHOLD = CACHE_ENABLED ? `ICACHE_LINELENINBITS/32 : 1;
logic [`XLEN-1:0] PCPlus2F; logic [`XLEN-1:0] PCPlus2F;
logic TakeSpillF; logic TakeSpillF;
logic SpillF; logic SpillF, PossibleSpillF, FirstHalfCompressedF;
logic SelSpillF, SpillSaveF; logic SelSpillF, SpillSaveF;
logic [15:0] SpillDataLine0, SavedInstr; logic [15:0] InstrFirstHalfF;
typedef enum logic [1:0] {STATE_READY, STATE_SPILL} statetype; typedef enum logic [1:0] {STATE_READY, STATE_SPILL} statetype;
(* mark_debug = "true" *) statetype CurrState, NextState; (* mark_debug = "true" *) statetype CurrState, NextState;
@ -66,7 +66,8 @@ module spillsupport #(parameter CACHE_ENABLED)
// select between PCF and PCF+2 // select between PCF and PCF+2
mux2 #(`XLEN) pcspillmux(.d0(PCF), .d1(PCPlus2F), .s(SelSpillF), .y(PCFSpill)); mux2 #(`XLEN) pcspillmux(.d0(PCF), .d1(PCPlus2F), .s(SelSpillF), .y(PCFSpill));
assign SpillF = &PCF[$clog2(SPILLTHRESHOLD)+1:1]; assign PossibleSpillF = &PCF[$clog2(SPILLTHRESHOLD)+1:1];
assign SpillF = PossibleSpillF & ~FirstHalfCompressedF & ~IFUCacheBusStallD;
assign TakeSpillF = SpillF & ~IFUCacheBusStallD & ~(ITLBMissF | (`HPTW_WRITES_SUPPORTED & InstrDAPageFaultF)); assign TakeSpillF = SpillF & ~IFUCacheBusStallD & ~(ITLBMissF | (`HPTW_WRITES_SUPPORTED & InstrDAPageFaultF));
always_ff @(posedge clk) always_ff @(posedge clk)
@ -87,16 +88,16 @@ module spillsupport #(parameter CACHE_ENABLED)
assign SelNextSpillF = (CurrState == STATE_READY & TakeSpillF) | assign SelNextSpillF = (CurrState == STATE_READY & TakeSpillF) |
(CurrState == STATE_SPILL & IFUCacheBusStallD); (CurrState == STATE_SPILL & IFUCacheBusStallD);
assign SpillSaveF = (CurrState == STATE_READY) & TakeSpillF; assign SpillSaveF = (CurrState == STATE_READY) & TakeSpillF;
assign SavedInstr = CACHE_ENABLED ? InstrRawF[15:0] : InstrRawF[31:16];
flopenr #(16) SpillInstrReg(.clk(clk), flopenr #(16) SpillInstrReg(.clk(clk),
.en(SpillSaveF & ~Flush), .en(SpillSaveF & ~Flush),
.reset(reset), .reset(reset),
.d(InstrRawF[15:0]), .d(InstrRawF[15:0]),
.q(SpillDataLine0)); .q(InstrFirstHalfF));
mux2 #(32) postspillmux(.d0(InstrRawF), .d1({InstrRawF[15:0], SpillDataLine0}), .s(SpillF), mux2 #(32) postspillmux(.d0(InstrRawF), .d1({InstrRawF[15:0], InstrFirstHalfF}), .s(SelSpillF),
.y(PostSpillInstrRawF)); .y(PostSpillInstrRawF));
assign CompressedF = PostSpillInstrRawF[1:0] != 2'b11; assign CompressedF = PostSpillInstrRawF[1:0] != 2'b11;
assign FirstHalfCompressedF = InstrRawF[1:0] != 2'b11;
endmodule endmodule