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LSU and IFU cleanup.

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This commit is contained in:
Ross Thompson 2022-01-28 15:26:06 -06:00
parent 2e00186eea
commit ac50a36aac
2 changed files with 32 additions and 42 deletions
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68
pipelined/src/ifu/ifu.sv
View File

@ -91,7 +91,9 @@ module ifu (
logic [`XLEN-1:0] PCPlus2or4F, PCLinkD;
logic [`XLEN-3:0] PCPlusUpperF;
logic CompressedF;
logic [31:0] InstrRawD, FinalInstrRawF, InstrRawF;
logic [31:0] InstrRawD, InstrRawF;
logic [`XLEN-1:0] FinalInstrRawF;
logic [31:0] InstrE;
logic [`XLEN-1:0] PCD;
@ -162,16 +164,10 @@ module ifu (
assign PCPF = PCF;
assign CacheableF = '1;
end
// conditional
// 1. ram // controlled by `MEM_IROM
// 2. cache // `MEM_ICACHE
// 3. wire pass-through
// If we have `MEM_IROM we don't have the bus controller
// otherwise we have the bus controller and either a cache or a passthrough.
// *** make this area look like LSU, including moving I$. Hide localparams in submodules when feasible
////////////////////////////////////////////////////////////////////////////////////////////////
// Memory
////////////////////////////////////////////////////////////////////////////////////////////////
localparam integer WORDSPERLINE = `MEM_ICACHE ? `ICACHE_LINELENINBITS/`XLEN : 1;
localparam integer LOGWPL = `MEM_ICACHE ? $clog2(WORDSPERLINE) : 1;
@ -181,23 +177,20 @@ module ifu (
localparam integer LINEBYTELEN = LINELEN/8;
localparam integer OFFSETLEN = $clog2(LINEBYTELEN);
logic [LOGWPL-1:0] WordCount;
logic [LINELEN-1:0] ICacheMemWriteData;
logic [LINELEN-1:0] ICacheMemWriteData; /// used outside bus
logic ICacheBusAck;
logic [`PA_BITS-1:0] LocalIFUBusAdr;
logic [`PA_BITS-1:0] ICacheBusAdr;
logic SelUncachedAdr;
logic SelUncachedAdr; // used outside bus
if (`MEM_IROM) begin : irom
logic [`XLEN-1:0] FinalInstrRawF_FIXME;
simpleram #(
.BASE(`RAM_BASE), .RANGE(`RAM_RANGE)) ram (
.clk,
.a(CPUBusy | reset ? PCPF[31:0] : PCNextFSpill[31:0]), // mux is also inside $, have to replay address if CPU is stalled.
.we(1'b0),
.wd(0), .rd(FinalInstrRawF_FIXME));
assign FinalInstrRawF = FinalInstrRawF_FIXME[31:0];
.wd(0), .rd(FinalInstrRawF));
assign BusStall = 0;
assign IFUBusRead = 0;
assign ICacheBusAck = 0;
@ -205,36 +198,36 @@ module ifu (
assign IFUBusAdr = 0;
assign ICacheStallF = '0;
end else begin : bus
genvar index;
for (index = 0; index < WORDSPERLINE; index++) begin:fetchbuffer
flopen #(`XLEN) fb(.clk(clk),
.en(IFUBusAck & IFUBusRead & (index == WordCount)),
.d(IFUBusHRDATA),
.q(ICacheMemWriteData[(index+1)*`XLEN-1:index*`XLEN]));
end
logic [LOGWPL-1:0] WordCount;
assign LocalIFUBusAdr = SelUncachedAdr ? PCPF : ICacheBusAdr;
assign IFUBusAdr = ({{`PA_BITS-LOGWPL{1'b0}}, WordCount} << $clog2(`XLEN/8)) + LocalIFUBusAdr;
genvar index;
for (index = 0; index < WORDSPERLINE; index++) begin:fetchbuffer
flopen #(`XLEN) fb(.clk(clk),
.en(IFUBusAck & IFUBusRead & (index == WordCount)),
.d(IFUBusHRDATA),
.q(ICacheMemWriteData[(index+1)*`XLEN-1:index*`XLEN]));
end
busfsm #(WordCountThreshold, LOGWPL, `MEM_ICACHE)
busfsm(.clk, .reset, .IgnoreRequest(ITLBMissF),
.LSURWM(2'b10), .DCacheFetchLine(ICacheFetchLine), .DCacheWriteLine(1'b0),
.LSUBusAck(IFUBusAck),
.CPUBusy, .CacheableM(CacheableF),
.BusStall, .LSUBusWrite(), .LSUBusRead(IFUBusRead), .DCacheBusAck(ICacheBusAck),
.BusCommittedM(), .SelUncachedAdr(SelUncachedAdr), .WordCount);
assign LocalIFUBusAdr = SelUncachedAdr ? PCPF : ICacheBusAdr;
assign IFUBusAdr = ({{`PA_BITS-LOGWPL{1'b0}}, WordCount} << $clog2(`XLEN/8)) + LocalIFUBusAdr;
busfsm #(WordCountThreshold, LOGWPL, `MEM_ICACHE)
busfsm(.clk, .reset, .IgnoreRequest(ITLBMissF),
.LSURWM(2'b10), .DCacheFetchLine(ICacheFetchLine), .DCacheWriteLine(1'b0),
.LSUBusAck(IFUBusAck),
.CPUBusy, .CacheableM(CacheableF),
.BusStall, .LSUBusWrite(), .LSUBusRead(IFUBusRead), .DCacheBusAck(ICacheBusAck),
.BusCommittedM(), .SelUncachedAdr(SelUncachedAdr), .WordCount);
if(`MEM_ICACHE) begin : icache
logic [1:0] IFURWF;
assign IFURWF = CacheableF ? 2'b10 : 2'b00;
logic [`XLEN-1:0] FinalInstrRawF_FIXME;
cache #(.LINELEN(`ICACHE_LINELENINBITS),
.NUMLINES(`ICACHE_WAYSIZEINBYTES*8/`ICACHE_LINELENINBITS),
.NUMWAYS(`ICACHE_NUMWAYS), .DCACHE(0))
icache(.clk, .reset, .CPUBusy, .IgnoreRequest(ITLBMissF), .CacheMemWriteData(ICacheMemWriteData) , .CacheBusAck(ICacheBusAck),
.CacheBusAdr(ICacheBusAdr), .CacheStall(ICacheStallF), .ReadDataWord(FinalInstrRawF_FIXME),
.CacheBusAdr(ICacheBusAdr), .CacheStall(ICacheStallF), .ReadDataWord(FinalInstrRawF),
.CacheFetchLine(ICacheFetchLine),
.CacheWriteLine(),
.ReadDataLineSets(),
@ -249,7 +242,6 @@ module ifu (
.CacheCommitted(),
.InvalidateCacheM(InvalidateICacheM));
assign FinalInstrRawF = FinalInstrRawF_FIXME[31:0];
end else begin : passthrough
assign ICacheFetchLine = '0;
assign ICacheBusAdr = '0;
@ -258,8 +250,6 @@ module ifu (
assign ICacheAccess = CacheableF;
assign ICacheMiss = CacheableF;
end
end
@ -271,7 +261,7 @@ module ifu (
// select between dcache and direct from the BUS. Always selected if no dcache.
// handled in the busfsm.
mux2 #(32) UnCachedInstrMux(.d0(FinalInstrRawF), .d1(ICacheMemWriteData[31:0]), .s(SelUncachedAdr), .y(InstrRawF));
mux2 #(32) UnCachedInstrMux(.d0(FinalInstrRawF[31:0]), .d1(ICacheMemWriteData[31:0]), .s(SelUncachedAdr), .y(InstrRawF));
assign IFUCacheBusStallF = ICacheStallF | BusStall;
assign IFUStallF = IFUCacheBusStallF | SelNextSpillF;

6
pipelined/src/lsu/lsu.sv
View File

@ -270,13 +270,13 @@ module lsu (
assign LocalLSUBusAdr = SelUncachedAdr ? LSUPAdrM : DCacheBusAdr ;
assign LSUBusAdr = ({{`PA_BITS-LOGWPL{1'b0}}, WordCount} << $clog2(`XLEN/8)) + LocalLSUBusAdr;
assign PreLSUBusHWDATA = ReadDataLineSetsM[WordCount];
assign PreLSUBusHWDATA = ReadDataLineSetsM[WordCount]; // only in lsu, not ifu
// exclude the subword write for uncached. We don't read the data first so we cannot
// select the subword by masking. Subword write also exists inside the uncore to
// suport subword masking for i/o. I'm not sure if this is necessary.
assign LSUBusHWDATA = SelUncachedAdr ? FinalAMOWriteDataM : PreLSUBusHWDATA;
assign LSUBusHWDATA = SelUncachedAdr ? FinalAMOWriteDataM : PreLSUBusHWDATA; // only in lsu, not ifu
assign LSUBusSize = SelUncachedAdr ? LSUFunct3M : (`XLEN == 32 ? 3'b010 : 3'b011);
assign LSUBusSize = SelUncachedAdr ? LSUFunct3M : (`XLEN == 32 ? 3'b010 : 3'b011); // ifu: always the XLEN value.
// select between dcache and direct from the BUS. Always selected if no dcache.
mux2 #(`XLEN) UnCachedDataMux(.d0(ReadDataWordM),