整理

lab1/朱梓涵24325356/core/MemoryAccess.scala

@@ -0,0 +1,106 @@
+// Copyright 2022 Canbin Huang
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package riscv.core
+
+import chisel3._
+import chisel3.util._
+import peripheral.RAMBundle
+import riscv.Parameters
+
+class MemoryAccess extends Module {
+  val io = IO(new Bundle() {
+    val alu_result = Input(UInt(Parameters.DataWidth))
+    val reg2_data = Input(UInt(Parameters.DataWidth))
+    val memory_read_enable = Input(Bool())
+    val memory_write_enable = Input(Bool())
+    val funct3 = Input(UInt(3.W))
+
+    val wb_memory_read_data = Output(UInt(Parameters.DataWidth))
+
+    val memory_bundle = Flipped(new RAMBundle)
+  })
+  val mem_address_index = io.alu_result(log2Up(Parameters.WordSize) - 1, 0).asUInt
+
+  io.memory_bundle.write_enable := false.B
+  io.memory_bundle.write_data := 0.U
+  io.memory_bundle.address := io.alu_result
+  io.memory_bundle.write_strobe := VecInit(Seq.fill(Parameters.WordSize)(false.B))
+  io.wb_memory_read_data := 0.U
+
+  when(io.memory_read_enable) {
+    val data = io.memory_bundle.read_data
+    io.wb_memory_read_data := MuxLookup(
+      io.funct3,
+      0.U,
+      IndexedSeq(
+        InstructionsTypeL.lb -> MuxLookup(
+          mem_address_index,
+          Cat(Fill(24, data(31)), data(31, 24)),
+          IndexedSeq(
+            0.U -> Cat(Fill(24, data(7)), data(7, 0)),
+            1.U -> Cat(Fill(24, data(15)), data(15, 8)),
+            2.U -> Cat(Fill(24, data(23)), data(23, 16))
+          )
+        ),
+        InstructionsTypeL.lbu -> MuxLookup(
+          mem_address_index,
+          Cat(Fill(24, 0.U), data(31, 24)),
+          IndexedSeq(
+            0.U -> Cat(Fill(24, 0.U), data(7, 0)),
+            1.U -> Cat(Fill(24, 0.U), data(15, 8)),
+            2.U -> Cat(Fill(24, 0.U), data(23, 16))
+          )
+        ),
+        InstructionsTypeL.lh -> Mux(
+          mem_address_index === 0.U,
+          Cat(Fill(16, data(15)), data(15, 0)),
+          Cat(Fill(16, data(31)), data(31, 16))
+
+        ),
+        InstructionsTypeL.lhu -> Mux(
+          mem_address_index === 0.U,
+          Cat(Fill(16, 0.U), data(15, 0)),
+          Cat(Fill(16, 0.U), data(31, 16))
+        ),
+        InstructionsTypeL.lw -> data
+      )
+    )
+  }.elsewhen(io.memory_write_enable) {
+    io.memory_bundle.write_data := io.reg2_data
+    io.memory_bundle.write_enable := true.B
+    io.memory_bundle.write_strobe := VecInit(Seq.fill(Parameters.WordSize)(false.B))
+    when(io.funct3 === InstructionsTypeS.sb) {
+      io.memory_bundle.write_strobe(mem_address_index) := true.B
+      io.memory_bundle.write_data := io.reg2_data(Parameters.ByteBits, 0) << (mem_address_index << log2Up(Parameters.ByteBits).U)
+    }.elsewhen(io.funct3 === InstructionsTypeS.sh) {
+      when(mem_address_index === 0.U) {
+        for (i <- 0 until Parameters.WordSize / 2) {
+          io.memory_bundle.write_strobe(i) := true.B
+        }
+        io.memory_bundle.write_data := io.reg2_data(Parameters.WordSize / 2 * Parameters.ByteBits, 0)
+      }.otherwise {
+        for (i <- Parameters.WordSize / 2 until Parameters.WordSize) {
+          io.memory_bundle.write_strobe(i) := true.B
+        }
+        io.memory_bundle.write_data := io.reg2_data(Parameters.WordSize / 2 * Parameters.ByteBits, 0) << (Parameters
+          .WordSize / 2 * Parameters.ByteBits)
+      }
+    }.elsewhen(io.funct3 === InstructionsTypeS.sw) {
+      for (i <- 0 until Parameters.WordSize) {
+        io.memory_bundle.write_strobe(i) := true.B
+      }
+    }
+  }
+}