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refactor(dcache): 删除cache data forward

This commit is contained in:
Liphen 2023-12-28 13:40:54 +08:00
parent b45e0194fa
commit 11dff5ca0f
1 changed files with 3 additions and 14 deletions
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17
chisel/playground/src/cache/DCache.scala vendored
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@ -107,6 +107,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val dirty = RegInit(VecInit(Seq.fill(nindex)(VecInit(Seq.fill(nway)(false.B)))))
val lru = RegInit(VecInit(Seq.fill(nindex)(false.B))) // TODO:支持更多路数，目前只支持2路
// 对于uncached段使用writeFifo进行写回
val writeFifo = Module(new Queue(new WriteBufferUnit(), writeFifoDepth))
val writeFifo_axi_busy = RegInit(false.B)
val writeFifo_busy = (writeFifo.io.deq.valid || writeFifo_axi_busy)
@ -173,13 +174,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val saved_rdata = RegInit(0.U(XLEN.W))
// forward last stored data in data bram
val last_waddr = RegNext(replace_waddr)
val last_wstrb = RegInit(VecInit(Seq.fill(nway)(0.U(XLEN.W))))
val last_wdata = RegNext(replace_wdata)
val cache_data_forward = Wire(Vec(nway, UInt(XLEN.W)))
io.cpu.rdata := Mux(state === s_wait, saved_rdata, cache_data_forward(select_way))
io.cpu.rdata := Mux(state === s_wait, saved_rdata, data(select_way))
// bank tagv ram
for { i <- 0 until nway } {
@ -202,11 +197,6 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
tagRam.io.wdata := tag_wdata
tag_compare_valid(i) := tag(i) === io.cpu.tlb.ptag && valid(index)(i) && io.cpu.tlb.translation_ok
cache_data_forward(i) := Mux(
last_waddr === bank_addr,
((last_wstrb(i) & last_wdata) | (data(i) & (~last_wstrb(i)))),
data(i)
)
replace_wstrb(i) := Mux(
tag_compare_valid(i) && io.cpu.en && io.cpu.wen.orR && !io.cpu.tlb.uncached && state === s_idle && !tlb_fill,
@ -214,7 +204,6 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
victim.wstrb(i)
)
last_wstrb(i) := Cat((AXI_STRB_WID - 1 to 0 by -1).map(j => Fill(8, replace_wstrb(i)(j))))
}
val ar = RegInit(0.U.asTypeOf(new AR()))
@ -321,7 +310,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
dirty(index)(select_way) := true.B
}
when(!io.cpu.complete_single_request) {
saved_rdata := cache_data_forward(select_way)
saved_rdata := data(select_way)
state := s_wait
}
}