init repo

lab2/src/main/scala/peripheral/CharacterDisplay.scala

@@ -0,0 +1,84 @@
+// Copyright 2022 Howard Lau
+//
+// 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 peripheral
+
+import chisel3.util.{MuxLookup, log2Up}
+import chisel3.{Bool, Bundle, Module, Mux, Output, UInt, Wire, _}
+import peripheral.ScreenInfo.{DisplayHorizontal, DisplayVertical}
+import riscv.Parameters
+
+object GlyphInfo {
+  val glyphWidth = 8
+  val glyphHeight = 16
+  // ASCII printable characters start from here
+  val spaceIndex = 1
+}
+
+object ScreenInfo {
+  val DisplayHorizontal = 640
+  val DisplayVertical = 480
+}
+
+object CharacterBufferInfo {
+  val CharCols = DisplayHorizontal / GlyphInfo.glyphWidth
+  val CharRows = DisplayVertical / GlyphInfo.glyphHeight
+  val Chars = CharCols * CharRows
+}
+
+class CharacterDisplay extends Module {
+  val io = IO(new Bundle() {
+    val bundle = new RAMBundle()
+
+    val x = Input(UInt(16.W))
+    val y = Input(UInt(16.W))
+    val video_on = Input(Bool())
+
+    val rgb = Output(UInt(24.W))
+  })
+
+  val mem = Module(new BlockRAM(CharacterBufferInfo.Chars / Parameters.WordSize))
+  mem.io.write_enable := io.bundle.write_enable
+  mem.io.write_data := io.bundle.write_data
+  mem.io.write_address := io.bundle.address
+  mem.io.write_strobe := io.bundle.write_strobe
+  mem.io.read_address := io.bundle.address
+  io.bundle.read_data := mem.io.read_data
+
+
+  val font_rom = Module(new FontROM)
+  val row = (io.y >> log2Up(GlyphInfo.glyphHeight)).asUInt
+  val col = (io.x >> log2Up(GlyphInfo.glyphWidth)).asUInt
+  val char_index = (row * CharacterBufferInfo.CharCols.U) + col
+  val offset = char_index(1, 0)
+  val ch = Wire(UInt(8.W))
+
+  mem.io.debug_read_address := char_index
+  ch := MuxLookup(
+    offset,
+    0.U,
+    IndexedSeq(
+      0.U -> mem.io.debug_read_data(7, 0).asUInt,
+      1.U -> mem.io.debug_read_data(15, 8).asUInt,
+      2.U -> mem.io.debug_read_data(23, 16).asUInt,
+      3.U -> mem.io.debug_read_data(31, 24).asUInt
+    )
+  )
+  font_rom.io.glyph_index := Mux(ch >= 32.U, ch - 31.U, 0.U)
+  font_rom.io.glyph_y := io.y(log2Up(GlyphInfo.glyphHeight) - 1, 0)
+
+  // White if pixel_on and glyph pixel on
+  val glyph_x = io.x(log2Up(GlyphInfo.glyphWidth) - 1, 0)
+  io.rgb := Mux(io.video_on && font_rom.io.glyph_pixel_byte(glyph_x), 0xFFFFFF.U, 0.U)
+}

lab2/src/main/scala/peripheral/Dummy.scala

@@ -0,0 +1,29 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+import riscv.Parameters
+
+// A dummy master that never initiates reads or writes
+class Dummy extends Module {
+  val io = IO(new Bundle {
+    val bundle = Flipped(new RAMBundle)
+  })
+  io.bundle.write_strobe := VecInit(Seq.fill(Parameters.WordSize)(false.B))
+  io.bundle.write_data := 0.U
+  io.bundle.write_enable := false.B
+  io.bundle.address := 0.U
+}

lab2/src/main/scala/peripheral/FontROM.scala

@@ -0,0 +1,64 @@
+package peripheral
+
+import chisel3.experimental.{ChiselAnnotation, annotate}
+import chisel3.util.experimental.loadMemoryFromFileInline
+import chisel3.{Bundle, Input, Module, Output, SyncReadMem, UInt, _}
+import firrtl.annotations.MemorySynthInit
+
+import java.io.FileWriter
+import java.nio.file.Paths
+import javax.imageio.ImageIO
+
+class FontROM(fontBitmapFilename: String = "vga_font_8x16.bmp") extends Module {
+  val glyphWidth = GlyphInfo.glyphWidth
+  val glyphHeight = GlyphInfo.glyphHeight
+
+  val io = IO(new Bundle {
+    val glyph_index = Input(UInt(7.W))
+    val glyph_y = Input(UInt(4.W))
+
+    val glyph_pixel_byte = Output(UInt(8.W))
+  })
+
+  annotate(new ChiselAnnotation {
+    override def toFirrtl =
+      MemorySynthInit
+  })
+
+  val (hexTxtPath, glyphCount) = readFontBitmap()
+  val mem = SyncReadMem(glyphCount, UInt(8.W))
+  loadMemoryFromFileInline(mem, hexTxtPath.toString.replaceAll("\\\\", "/"))
+  io.glyph_pixel_byte := mem.read(io.glyph_index * GlyphInfo.glyphHeight.U + io.glyph_y, true.B)
+
+  def readFontBitmap() = {
+    val inputStream = getClass.getClassLoader.getResourceAsStream(fontBitmapFilename)
+    val image = ImageIO.read(inputStream)
+
+    val glyphColumns = image.getWidth() / glyphWidth
+    val glyphRows = image.getHeight / glyphHeight
+    val glyphCount = glyphColumns * glyphRows
+    val glyphs = new Array[UInt](glyphCount * GlyphInfo.glyphHeight)
+
+    for (row <- 0 until glyphRows) {
+      for (col <- 0 until glyphColumns) {
+        for (i <- 0 until glyphHeight) {
+          var lineInt = 0
+          for (j <- 0 until glyphWidth) {
+            if (image.getRGB(col * glyphWidth + j, row * glyphHeight + i) != 0xFFFFFFFF) {
+              lineInt |= (1 << j)
+            }
+          }
+          glyphs((row * glyphColumns + col) * GlyphInfo.glyphHeight + i) = lineInt.U(8.W)
+        }
+      }
+    }
+    val currentDir = System.getProperty("user.dir")
+    val hexTxtPath = Paths.get(currentDir, "verilog", f"${fontBitmapFilename}.txt")
+    val writer = new FileWriter(hexTxtPath.toString)
+    for (i <- glyphs.indices) {
+      writer.write(f"@$i%x\n${glyphs(i).litValue}%02x\n")
+    }
+    writer.close()
+    (hexTxtPath, glyphs.length)
+  }
+}

lab2/src/main/scala/peripheral/HDMIDisplay.scala

@@ -0,0 +1,394 @@
+// Copyright 2022 hrpccs
+//
+// 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 peripheral
+
+import chisel3._
+import chisel3.util._
+
+class HDMISync extends Module {
+  val io = IO(new Bundle {
+    val hsync = Output(Bool())
+    val vsync = Output(Bool())
+    val video_on = Output(Bool())
+    val p_tick = Output(Bool())
+    val f_tick = Output(Bool())
+    val x = Output(UInt(10.W))
+    val y = Output(UInt(10.W))
+    val x_next = Output(UInt(10.W))
+    val y_next = Output(UInt(10.W))
+  })
+
+  val DisplayHorizontal = ScreenInfo.DisplayHorizontal
+  val DisplayVertical = ScreenInfo.DisplayVertical
+
+  val BorderLeft = 48
+  val BorderRight = 16
+  val BorderTop = 10
+  val BorderBottom = 33
+
+  val RetraceHorizontal = 96
+  val RetraceVertical = 2
+
+  val MaxHorizontal = DisplayHorizontal + BorderLeft + BorderRight + RetraceHorizontal - 1
+  val MaxVertical = DisplayVertical + BorderTop + BorderBottom + RetraceVertical - 1
+
+  val RetraceHorizontalStart = DisplayHorizontal + BorderRight
+  val RetraceHorizontalEnd = RetraceHorizontalStart + RetraceHorizontal - 1
+
+  val RetraceVerticalStart = DisplayVertical + BorderBottom
+  val RetraceVerticalEnd = RetraceVerticalStart + RetraceVertical - 1
+
+  val pixel = RegInit(UInt(3.W), 0.U)
+  val pixel_next = Wire(UInt(3.W))
+  val pixel_tick = Wire(Bool())
+
+  val v_count_reg = RegInit(UInt(10.W), 0.U)
+  val h_count_reg = RegInit(UInt(10.W), 0.U)
+
+  val v_count_next = Wire(UInt(10.W))
+  val h_count_next = Wire(UInt(10.W))
+
+  val vsync_reg = RegInit(Bool(), false.B)
+  val hsync_reg = RegInit(Bool(), false.B)
+
+  val vsync_next = Wire(Bool())
+  val hsync_next = Wire(Bool())
+
+  pixel_next := Mux(pixel === 4.U, 0.U, pixel + 1.U)
+  pixel_tick := pixel === 0.U
+
+  h_count_next := Mux(
+    pixel_tick,
+    Mux(h_count_reg === MaxHorizontal.U, 0.U, h_count_reg + 1.U),
+    h_count_reg
+  )
+
+  v_count_next := Mux(
+    pixel_tick && h_count_reg === MaxHorizontal.U,
+    Mux(v_count_reg === MaxVertical.U, 0.U, v_count_reg + 1.U),
+    v_count_reg
+  )
+
+  hsync_next := h_count_reg >= RetraceHorizontalStart.U && h_count_reg <= RetraceHorizontalEnd.U
+  vsync_next := v_count_reg >= RetraceVerticalStart.U && v_count_reg <= RetraceVerticalEnd.U
+
+  pixel := pixel_next
+  hsync_reg := hsync_next
+  vsync_reg := vsync_next
+  v_count_reg := v_count_next
+  h_count_reg := h_count_next
+
+  io.video_on := h_count_reg < DisplayHorizontal.U && v_count_reg < DisplayVertical.U
+  io.hsync := hsync_reg
+  io.vsync := vsync_reg
+  io.x := h_count_reg
+  io.y := v_count_reg
+  io.x_next := h_count_next
+  io.y_next := v_count_next
+  io.p_tick := pixel_tick
+  io.f_tick := io.x === 0.U && io.y === 0.U
+}
+
+class TMDS_encoder extends Module {
+  val io = IO(new Bundle() {
+    val video_data = Input(UInt(8.W)) //r,g,b,8bit
+    val control_data = Input(UInt(2.W))
+    val video_on = Input(Bool())
+    val TMDS = Output(UInt(10.W))
+  })
+  val Nb1s = PopCount(io.video_data)
+  val xored = xorfct(io.video_data)
+  val xnored = xnorfct(io.video_data)
+  val XNOR = (Nb1s > 4.U(4.W)) || (Nb1s === 4.U(4.W) && io.video_data(0) === 0.U)
+  val q_m = RegInit(0.U(9.W))
+  val diffSize = 4
+  val diff = RegInit(0.S(diffSize.W))
+  q_m := Mux(
+    XNOR,
+    xnored,
+    xored
+  )
+  val disparitySize = 4
+  val disparityReg = RegInit(0.S(disparitySize.W))
+  diff := PopCount(q_m).asSInt - 4.S
+  val doutReg = RegInit("b1010101011".U(10.W))
+
+  def xorfct(value: UInt): UInt = {
+    val vin = VecInit(value.asBools)
+    val res = VecInit(511.U.asBools)
+    res(0) := vin(0)
+    for (i <- 1 to 7) {
+      res(i) := res(i - 1) ^ vin(i)
+    }
+    res(8) := 1.U
+    res.asUInt
+  }
+
+  def xnorfct(value: UInt): UInt = {
+    val vin = VecInit(value.asBools)
+    val res = VecInit(511.U.asBools)
+    res(0) := vin(0)
+    for (i <- 1 to 7) {
+      res(i) := !(res(i - 1) ^ vin(i))
+    }
+    res(8) := 0.U
+    res.asUInt
+  }
+
+  when(io.video_on === false.B) {
+    disparityReg := 0.S
+    doutReg := "b1010101011".U(10.W)
+    switch(io.control_data) {
+      is("b00".U(2.W)) {
+        doutReg := "b1101010100".U(10.W)
+      }
+      is("b01".U(2.W)) {
+        doutReg := "b0010101011".U(10.W)
+      }
+      is("b10".U(2.W)) {
+        doutReg := "b0101010100".U(10.W)
+      }
+    }
+  }.otherwise {
+    when(disparityReg === 0.S || diff === 0.S) {
+      when(q_m(8) === false.B) {
+        doutReg := "b10".U(2.W) ## ~q_m(7, 0)
+        disparityReg := disparityReg - diff
+      }.otherwise {
+        doutReg := "b01".U(2.W) ## q_m(7, 0)
+        disparityReg := disparityReg + diff
+      }
+    }.elsewhen((!diff(diffSize - 1) && !disparityReg(disparitySize - 1))
+      || (diff(diffSize - 1) && disparityReg(disparitySize - 1))) {
+      doutReg := 1.U(1.W) ## q_m(8) ## ~q_m(7, 0)
+      when(q_m(8)) {
+        disparityReg := disparityReg + 1.S - diff
+      }.otherwise {
+        disparityReg := disparityReg - diff
+      }
+    }.otherwise {
+      doutReg := 0.U(1.W) ## q_m
+      when(q_m(8)) {
+        disparityReg := disparityReg + diff
+      }.otherwise {
+        disparityReg := disparityReg - 1.S + diff
+      }
+    }
+  }
+
+  io.TMDS := doutReg
+}
+
+class HDMIDisplay extends Module {
+  val io = IO(new Bundle() {
+    val rgb = Input(UInt(24.W))
+    val x = Output(UInt(16.W))
+    val y = Output(UInt(16.W))
+    val x_next = Output(UInt(16.W))
+    val y_next = Output(UInt(16.W))
+    val video_on = Output(Bool())
+
+    val TMDSclk_p = Output(Bool())
+    val TMDSdata_p = Output(UInt(3.W))
+    val TMDSclk_n = Output(Bool())
+    val TMDSdata_n = Output(UInt(3.W))
+  })
+  val rgb = io.rgb
+  val pixel_clk = Wire(Bool())
+  val hsync = Wire(Bool())
+  val vsync = Wire(Bool())
+  val sync = Module(new HDMISync)
+
+  io.x := sync.io.x
+  io.y := sync.io.y
+  io.x_next := sync.io.x_next
+  io.y_next := sync.io.y_next
+  io.video_on := sync.io.video_on
+
+  hsync := sync.io.hsync
+  vsync := sync.io.vsync
+  pixel_clk := sync.io.p_tick
+
+  // TMDS_PLLVR is a vivado IP core, check it in /verilog/pynq/TMDS_PLLVR.v
+  val serial_clk = Wire(Clock())
+  val pll_lock = Wire(Bool())
+  val tmdspll = Module(new TMDS_PLLVR)
+  val rst = Wire(Reset())
+  tmdspll.io.clkin := pixel_clk.asClock
+  serial_clk := tmdspll.io.clkout
+  pll_lock := tmdspll.io.lock
+  tmdspll.io.reset := reset
+  rst := ~pll_lock
+
+  val tmds = Wire(UInt(3.W))
+  val tmds_clk = Wire(Bool())
+  withClockAndReset(pixel_clk.asClock, rst) {
+    val tmds_channel1 = Wire(UInt(10.W))
+    val tmds_channel2 = Wire(UInt(10.W))
+    val tmds_channel0 = Wire(UInt(10.W))
+
+    val tmds_green = Module(new TMDS_encoder)
+    val tmds_red = Module(new TMDS_encoder)
+    val tmds_blue = Module(new TMDS_encoder)
+
+    tmds_red.io.video_on := sync.io.video_on
+    tmds_blue.io.video_on := sync.io.video_on
+    tmds_green.io.video_on := sync.io.video_on
+
+    tmds_blue.io.control_data := sync.io.vsync ## sync.io.hsync
+    tmds_green.io.control_data := 0.U
+    tmds_red.io.control_data := 0.U
+
+    tmds_red.io.video_data := rgb(23, 16)
+    tmds_blue.io.video_data := rgb(7, 0)
+    tmds_green.io.video_data := rgb(15, 8)
+
+    tmds_channel0 := tmds_blue.io.TMDS
+    tmds_channel1 := tmds_green.io.TMDS
+    tmds_channel2 := tmds_red.io.TMDS
+
+    val serdesBlue = Module(new Oser10Module())
+    serdesBlue.io.data := tmds_channel0
+    serdesBlue.io.fclk := serial_clk
+
+    val serdesGreen = Module(new Oser10Module())
+    serdesGreen.io.data := tmds_channel1
+    serdesGreen.io.fclk := serial_clk
+
+    val serdesRed = Module(new Oser10Module())
+    serdesRed.io.data := tmds_channel2
+    serdesRed.io.fclk := serial_clk
+
+    tmds := serdesRed.io.q ## serdesGreen.io.q ## serdesBlue.io.q
+
+    //serdesCLk : 25Mhz ,Why not directly use p_tick?
+    //cause Duty Ratio of p_tick is 10% , while which of serdesCLk is 50%
+    val serdesClk = Module(new Oser10Module())
+    serdesClk.io.data := "b1111100000".U(10.W)
+    serdesClk.io.fclk := serial_clk
+
+    tmds_clk := serdesClk.io.q
+
+    val buffDiffBlue = Module(new OBUFDS)
+    buffDiffBlue.io.I := tmds(0)
+    val buffDiffGreen = Module(new OBUFDS)
+    buffDiffGreen.io.I := tmds(1)
+    val buffDiffRed = Module(new OBUFDS)
+    buffDiffRed.io.I := tmds(2)
+    val buffDiffClk = Module(new OBUFDS)
+    buffDiffClk.io.I := tmds_clk
+
+    io.TMDSclk_p := buffDiffClk.io.O
+    io.TMDSclk_n := buffDiffClk.io.OB
+    io.TMDSdata_p := buffDiffRed.io.O ## buffDiffGreen.io.O ## buffDiffBlue.io.O
+    io.TMDSdata_n := buffDiffRed.io.OB ## buffDiffGreen.io.OB ## buffDiffBlue.io.OB
+  }
+}
+
+//----------------------------------------
+//PLL frequency multiplier using BlackBox
+class TMDS_PLLVR extends BlackBox {
+  val io = IO(new Bundle {
+    val clkin = Input(Clock())
+    val reset = Input(Reset())
+    val clkout = Output(Clock())
+    val clkoutd = Output(Clock())
+    val lock = Output(Bool())
+  })
+}
+
+/* OSER10 : serializer 10:1*/
+class OSER10 extends Module {
+  val io = IO(new Bundle {
+    val Q = Output(Bool()) // OSER10 data output signal
+    val D0 = Input(Bool())
+    val D1 = Input(Bool())
+    val D2 = Input(Bool())
+    val D3 = Input(Bool())
+    val D4 = Input(Bool())
+    val D5 = Input(Bool())
+    val D6 = Input(Bool())
+    val D7 = Input(Bool())
+    val D8 = Input(Bool())
+    val D9 = Input(Bool()) //  OSER10 data input signal
+    val PCLK = Input(Clock()) // Primary clock input signal
+    val FCLK = Input(Clock()) // High speed clock input signal
+    val RESET = Input(Reset()) // Asynchronous reset input signal,
+    //active-high.
+  })
+  withClockAndReset(io.FCLK, io.RESET) {
+    val count = RegInit(0.U(4.W))
+    val countnext = Wire(UInt(4.W))
+    io.Q := MuxLookup(
+      count,
+      0.U,
+      IndexedSeq(
+        0.U -> io.D0.asBool,
+        1.U -> io.D1.asBool,
+        2.U -> io.D2.asBool,
+        3.U -> io.D3.asBool,
+        4.U -> io.D4.asBool,
+        5.U -> io.D5.asBool,
+        6.U -> io.D6.asBool,
+        7.U -> io.D7.asBool,
+        8.U -> io.D8.asBool,
+        9.U -> io.D9.asBool
+      )
+    )
+    countnext := Mux(
+      count === 9.U, 0.U, count + 1.U
+    )
+    count := countnext
+  }
+}
+
+class Oser10Module extends Module {
+  val io = IO(new Bundle {
+    val q = Output(Bool())
+    val data = Input(UInt(10.W))
+    val fclk = Input(Clock()) // Fast clock
+  })
+
+  val osr10 = Module(new OSER10())
+  io.q := osr10.io.Q
+  osr10.io.D0 := io.data(0)
+  osr10.io.D1 := io.data(1)
+  osr10.io.D2 := io.data(2)
+  osr10.io.D3 := io.data(3)
+  osr10.io.D4 := io.data(4)
+  osr10.io.D5 := io.data(5)
+  osr10.io.D6 := io.data(6)
+  osr10.io.D7 := io.data(7)
+  osr10.io.D8 := io.data(8)
+  osr10.io.D9 := io.data(9)
+  osr10.io.PCLK := clock
+  osr10.io.FCLK := io.fclk
+  osr10.io.RESET := reset
+}
+
+/* lvds output */
+class OBUFDS extends BlackBox {
+  val io = IO(new Bundle {
+    val O = Output(Bool())
+    val OB = Output(Bool())
+    val I = Input(Bool())
+  })
+}
+//-----------------------------------------
+
+
+//-----------------------------------------
+
+

lab2/src/main/scala/peripheral/InstructionROM.scala

@@ -0,0 +1,68 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+import chisel3.experimental.{ChiselAnnotation, annotate}
+import chisel3.util.experimental.loadMemoryFromFileInline
+import firrtl.annotations.MemorySynthInit
+import riscv.Parameters
+
+import java.io.FileWriter
+import java.nio.file.{Files, Paths}
+import java.nio.{ByteBuffer, ByteOrder}
+
+class InstructionROM(instructionFilename: String) extends Module {
+  val io = IO(new Bundle {
+    val address = Input(UInt(Parameters.AddrWidth))
+    val data = Output(UInt(Parameters.InstructionWidth))
+  })
+
+  val (instructionsInitFile, capacity) = readAsmBinary(instructionFilename)
+  val mem = Mem(capacity, UInt(Parameters.InstructionWidth))
+  annotate(new ChiselAnnotation {
+    override def toFirrtl =
+      MemorySynthInit
+  })
+  loadMemoryFromFileInline(mem, instructionsInitFile.toString.replaceAll("\\\\", "/"))
+  io.data := mem.read(io.address)
+
+  def readAsmBinary(filename: String) = {
+    val inputStream = if (Files.exists(Paths.get(filename))) {
+      Files.newInputStream(Paths.get(filename))
+    } else {
+      getClass.getClassLoader.getResourceAsStream(filename)
+    }
+    var instructions = new Array[BigInt](0)
+    val arr = new Array[Byte](4)
+    while (inputStream.read(arr) == 4) {
+      val instBuf = ByteBuffer.wrap(arr)
+      instBuf.order(ByteOrder.LITTLE_ENDIAN)
+      val inst = BigInt(instBuf.getInt() & 0xFFFFFFFFL)
+      instructions = instructions :+ inst
+    }
+    instructions = instructions :+ BigInt(0x00000013L)
+    instructions = instructions :+ BigInt(0x00000013L)
+    instructions = instructions :+ BigInt(0x00000013L)
+    val currentDir = System.getProperty("user.dir")
+    val exeTxtPath = Paths.get(currentDir, "verilog", f"${instructionFilename}.txt")
+    val writer = new FileWriter(exeTxtPath.toString)
+    for (i <- instructions.indices) {
+      writer.write(f"@$i%x\n${instructions(i)}%08x\n")
+    }
+    writer.close()
+    (exeTxtPath, instructions.length)
+  }
+}

lab2/src/main/scala/peripheral/Memory.scala

@@ -0,0 +1,77 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+import chisel3.util._
+import riscv.Parameters
+
+class RAMBundle extends Bundle {
+  val address = Input(UInt(Parameters.AddrWidth))
+  val write_data = Input(UInt(Parameters.DataWidth))
+  val write_enable = Input(Bool())
+  val write_strobe = Input(Vec(Parameters.WordSize, Bool()))
+  val read_data = Output(UInt(Parameters.DataWidth))
+}
+// The purpose of this module is to help the synthesis tool recognize
+// our memory as a Block RAM template
+class BlockRAM(capacity: Int) extends Module {
+  val io = IO(new Bundle {
+    val read_address = Input(UInt(Parameters.AddrWidth))
+    val write_address = Input(UInt(Parameters.AddrWidth))
+    val write_data = Input(UInt(Parameters.DataWidth))
+    val write_enable = Input(Bool())
+    val write_strobe = Input(Vec(Parameters.WordSize, Bool()))
+
+    val debug_read_address = Input(UInt(Parameters.AddrWidth))
+
+    val read_data = Output(UInt(Parameters.DataWidth))
+    val debug_read_data = Output(UInt(Parameters.DataWidth))
+  })
+  val mem = SyncReadMem(capacity, Vec(Parameters.WordSize, UInt(Parameters.ByteWidth)))
+  when(io.write_enable) {
+    val write_data_vec = Wire(Vec(Parameters.WordSize, UInt(Parameters.ByteWidth)))
+    for (i <- 0 until Parameters.WordSize) {
+      write_data_vec(i) := io.write_data((i + 1) * Parameters.ByteBits - 1, i * Parameters.ByteBits)
+    }
+    mem.write((io.write_address >> 2.U).asUInt, write_data_vec, io.write_strobe)
+  }
+  io.read_data := mem.read((io.read_address >> 2.U).asUInt, true.B).asUInt
+  io.debug_read_data := mem.read((io.debug_read_address >> 2.U).asUInt, true.B).asUInt
+}
+
+class Memory(capacity: Int) extends Module {
+  val io = IO(new Bundle {
+    val bundle = new RAMBundle
+
+    val instruction = Output(UInt(Parameters.DataWidth))
+    val instruction_address = Input(UInt(Parameters.AddrWidth))
+
+    val debug_read_address = Input(UInt(Parameters.AddrWidth))
+    val debug_read_data = Output(UInt(Parameters.DataWidth))
+  })
+
+  val mem = SyncReadMem(capacity, Vec(Parameters.WordSize, UInt(Parameters.ByteWidth)))
+  when(io.bundle.write_enable) {
+    val write_data_vec = Wire(Vec(Parameters.WordSize, UInt(Parameters.ByteWidth)))
+    for (i <- 0 until Parameters.WordSize) {
+      write_data_vec(i) := io.bundle.write_data((i + 1) * Parameters.ByteBits - 1, i * Parameters.ByteBits)
+    }
+    mem.write((io.bundle.address >> 2.U).asUInt, write_data_vec, io.bundle.write_strobe)
+  }
+  io.bundle.read_data := mem.read((io.bundle.address >> 2.U).asUInt, true.B).asUInt
+  io.debug_read_data := mem.read((io.debug_read_address >> 2.U).asUInt, true.B).asUInt
+  io.instruction := mem.read((io.instruction_address >> 2.U).asUInt, true.B).asUInt
+}

lab2/src/main/scala/peripheral/ROMLoader.scala

@@ -0,0 +1,50 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+import riscv.Parameters
+
+class ROMLoader(capacity: Int) extends Module {
+  val io = IO(new Bundle {
+    val bundle = Flipped(new RAMBundle)
+
+    val rom_address = Output(UInt(Parameters.AddrWidth))
+    val rom_data = Input(UInt(Parameters.InstructionWidth))
+
+    val load_address = Input(UInt(Parameters.AddrWidth))
+    val load_finished = Output(Bool())
+  })
+
+  val address = RegInit(0.U(32.W))
+  val valid = RegInit(false.B)
+
+  io.bundle.write_strobe := VecInit(Seq.fill(Parameters.WordSize)(false.B))
+  io.bundle.address := 0.U
+  io.bundle.write_data := 0.U
+  io.bundle.write_enable := false.B
+  when(address <= (capacity - 1).U) {
+    io.bundle.write_enable := true.B
+    io.bundle.write_data := io.rom_data
+    io.bundle.address := (address << 2.U).asUInt + io.load_address
+    io.bundle.write_strobe := VecInit(Seq.fill(Parameters.WordSize)(true.B))
+    address := address + 1.U
+    when(address === (capacity - 1).U) {
+      valid := true.B
+    }
+  }
+  io.load_finished := valid
+  io.rom_address := address
+}

lab2/src/main/scala/peripheral/Timer.scala

@@ -0,0 +1,38 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+import chisel3.util._
+import riscv.Parameters
+
+class Timer extends Module {
+  val io = IO(new Bundle {
+    val bundle = new RAMBundle
+    val signal_interrupt = Output(Bool())
+
+    val debug_limit = Output(UInt(Parameters.DataWidth))
+    val debug_enabled = Output(Bool())
+  })
+
+  val count = RegInit(0.U(32.W))
+  val limit = RegInit(100000000.U(32.W))
+  io.debug_limit := limit
+  val enabled = RegInit(true.B)
+  io.debug_enabled := enabled
+
+  //lab2(CLINTCSR)
+  //finish the read-write for count,limit,enabled. And produce appropriate signal_interrupt
+}

lab2/src/main/scala/peripheral/UART.scala

@@ -0,0 +1,204 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+import chisel3.util._
+
+class UartIO extends DecoupledIO(UInt(8.W)) {
+}
+
+
+/**
+ * Transmit part of the UART.
+ * A minimal version without any additional buffering.
+ * Use a ready/valid handshaking.
+ */
+class Tx(frequency: Int, baudRate: Int) extends Module {
+  val io = IO(new Bundle {
+    val txd = Output(UInt(1.W))
+    val channel = Flipped(new UartIO())
+
+  })
+
+  val BIT_CNT = ((frequency + baudRate / 2) / baudRate - 1).U
+
+  val shiftReg = RegInit(0x7ff.U)
+  val cntReg = RegInit(0.U(20.W))
+  val bitsReg = RegInit(0.U(4.W))
+
+  io.channel.ready := (cntReg === 0.U) && (bitsReg === 0.U)
+  io.txd := shiftReg(0)
+
+  when(cntReg === 0.U) {
+
+    cntReg := BIT_CNT
+    when(bitsReg =/= 0.U) {
+      val shift = shiftReg >> 1
+      shiftReg := Cat(1.U, shift(9, 0))
+      bitsReg := bitsReg - 1.U
+    }.otherwise {
+      when(io.channel.valid) {
+        shiftReg := Cat(Cat(3.U, io.channel.bits), 0.U) // two stop bits, data, one start bit
+        bitsReg := 11.U
+      }.otherwise {
+        shiftReg := 0x7ff.U
+      }
+    }
+
+  }.otherwise {
+    cntReg := cntReg - 1.U
+  }
+}
+
+/**
+ * Receive part of the UART.
+ * A minimal version without any additional buffering.
+ * Use a ready/valid handshaking.
+ *
+ * The following code is inspired by Tommy's receive code at:
+ * https://github.com/tommythorn/yarvi
+ */
+class Rx(frequency: Int, baudRate: Int) extends Module {
+  val io = IO(new Bundle {
+    val rxd = Input(UInt(1.W))
+    val channel = new UartIO()
+
+  })
+
+  val BIT_CNT = ((frequency + baudRate / 2) / baudRate - 1).U
+  val START_CNT = ((3 * frequency / 2 + baudRate / 2) / baudRate - 1).U
+
+  // Sync in the asynchronous RX data, reset to 1 to not start reading after a reset
+  val rxReg = RegNext(RegNext(io.rxd, 1.U), 1.U)
+
+  val shiftReg = RegInit(0.U(8.W))
+  val cntReg = RegInit(0.U(20.W))
+  val bitsReg = RegInit(0.U(4.W))
+  val valReg = RegInit(false.B)
+
+  when(cntReg =/= 0.U) {
+    cntReg := cntReg - 1.U
+  }.elsewhen(bitsReg =/= 0.U) {
+    cntReg := BIT_CNT
+    shiftReg := Cat(rxReg, shiftReg >> 1)
+    bitsReg := bitsReg - 1.U
+    // the last shifted in
+    when(bitsReg === 1.U) {
+      valReg := true.B
+    }
+  }.elsewhen(rxReg === 0.U) { // wait 1.5 bits after falling edge of start
+    cntReg := START_CNT
+    bitsReg := 8.U
+  }
+
+  when(valReg && io.channel.ready) {
+    valReg := false.B
+  }
+
+  io.channel.bits := shiftReg
+  io.channel.valid := valReg
+}
+
+/**
+ * A single byte buffer with a ready/valid interface
+ */
+class Buffer extends Module {
+  val io = IO(new Bundle {
+    val in = Flipped(new UartIO())
+    val out = new UartIO()
+  })
+
+  val empty :: full :: Nil = Enum(2)
+  val stateReg = RegInit(empty)
+  val dataReg = RegInit(0.U(8.W))
+
+  io.in.ready := stateReg === empty
+  io.out.valid := stateReg === full
+
+  when(stateReg === empty) {
+    when(io.in.valid) {
+      dataReg := io.in.bits
+      stateReg := full
+    }
+  }.otherwise { // full
+    when(io.out.ready) {
+      stateReg := empty
+    }
+  }
+  io.out.bits := dataReg
+}
+
+/**
+ * A transmitter with a single buffer.
+ */
+class BufferedTx(frequency: Int, baudRate: Int) extends Module {
+  val io = IO(new Bundle {
+    val txd = Output(UInt(1.W))
+    val channel = Flipped(new UartIO())
+
+  })
+  val tx = Module(new Tx(frequency, baudRate))
+  val buf = Module(new Buffer)
+
+  buf.io.in <> io.channel
+  tx.io.channel <> buf.io.out
+  io.txd <> tx.io.txd
+}
+
+class Uart(frequency: Int, baudRate: Int) extends Module {
+  val io = IO(new Bundle {
+    val bundle = new RAMBundle
+    val rxd = Input(UInt(1.W))
+    val txd = Output(UInt(1.W))
+
+    val signal_interrupt = Output(Bool())
+  })
+  val interrupt = RegInit(false.B)
+  val rxData = RegInit(0.U)
+
+  val tx = Module(new BufferedTx(frequency, baudRate))
+  val rx = Module(new Rx(frequency, baudRate))
+
+  io.bundle.read_data := 0.U
+  when(io.bundle.address === 0x4.U) {
+    io.bundle.read_data := baudRate.U
+  }.elsewhen(io.bundle.address === 0xC.U) {
+    io.bundle.read_data := rxData
+    interrupt := false.B
+  }
+
+  tx.io.channel.valid := false.B
+  tx.io.channel.bits := 0.U
+  when(io.bundle.write_enable) {
+    when(io.bundle.address === 0x8.U) {
+      interrupt := io.bundle.write_data =/= 0.U
+    }.elsewhen(io.bundle.address === 0x10.U) {
+      tx.io.channel.valid := true.B
+      tx.io.channel.bits := io.bundle.write_data
+    }
+  }
+
+  io.txd := tx.io.txd
+  rx.io.rxd := io.rxd
+
+  io.signal_interrupt := interrupt
+  rx.io.channel.ready := false.B
+  when(rx.io.channel.valid) {
+    rx.io.channel.ready := true.B
+    rxData := rx.io.channel.bits
+    interrupt := true.B
+  }
+}

lab2/src/main/scala/peripheral/VGADisplay.scala

@@ -0,0 +1,116 @@
+// Copyright 2021 Howard Lau
+//
+// 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 peripheral
+
+import chisel3._
+
+
+class VGASync extends Module {
+  val io = IO(new Bundle {
+    val hsync = Output(Bool())
+    val vsync = Output(Bool())
+    val video_on = Output(Bool())
+    val p_tick = Output(Bool())
+    val f_tick = Output(Bool())
+    val x = Output(UInt(10.W))
+    val y = Output(UInt(10.W))
+  })
+
+  val DisplayHorizontal = ScreenInfo.DisplayHorizontal
+  val DisplayVertical = ScreenInfo.DisplayVertical
+
+  val BorderLeft = 48
+  val BorderRight = 16
+  val BorderTop = 10
+  val BorderBottom = 33
+
+  val RetraceHorizontal = 96
+  val RetraceVertical = 2
+
+  val MaxHorizontal = DisplayHorizontal + BorderLeft + BorderRight + RetraceHorizontal - 1
+  val MaxVertical = DisplayVertical + BorderTop + BorderBottom + RetraceVertical - 1
+
+  val RetraceHorizontalStart = DisplayHorizontal + BorderRight
+  val RetraceHorizontalEnd = RetraceHorizontalStart + RetraceHorizontal - 1
+
+  val RetraceVerticalStart = DisplayVertical + BorderBottom
+  val RetraceVerticalEnd = RetraceVerticalStart + RetraceVertical - 1
+
+  val pixel = RegInit(UInt(2.W), 0.U)
+  val pixel_next = Wire(UInt(2.W))
+  val pixel_tick = Wire(Bool())
+
+  val v_count_reg = RegInit(UInt(10.W), 0.U)
+  val h_count_reg = RegInit(UInt(10.W), 0.U)
+
+  val v_count_next = Wire(UInt(10.W))
+  val h_count_next = Wire(UInt(10.W))
+
+  val vsync_reg = RegInit(Bool(), false.B)
+  val hsync_reg = RegInit(Bool(), false.B)
+
+  val vsync_next = Wire(Bool())
+  val hsync_next = Wire(Bool())
+
+  pixel_next := pixel + 1.U
+  pixel_tick := pixel === 0.U
+
+  h_count_next := Mux(
+    pixel_tick,
+    Mux(h_count_reg === MaxHorizontal.U, 0.U, h_count_reg + 1.U),
+    h_count_reg
+  )
+
+  v_count_next := Mux(
+    pixel_tick && h_count_reg === MaxHorizontal.U,
+    Mux(v_count_reg === MaxVertical.U, 0.U, v_count_reg + 1.U),
+    v_count_reg
+  )
+
+  hsync_next := h_count_reg >= RetraceHorizontalStart.U && h_count_reg <= RetraceHorizontalEnd.U
+  vsync_next := v_count_reg >= RetraceVerticalStart.U && v_count_reg <= RetraceVerticalEnd.U
+
+  pixel := pixel_next
+  hsync_reg := hsync_next
+  vsync_reg := vsync_next
+  v_count_reg := v_count_next
+  h_count_reg := h_count_next
+
+  io.video_on := h_count_reg < DisplayHorizontal.U && v_count_reg < DisplayVertical.U
+  io.hsync := hsync_reg
+  io.vsync := vsync_reg
+  io.x := h_count_reg
+  io.y := v_count_reg
+  io.p_tick := pixel_tick
+  io.f_tick := io.x === 0.U && io.y === 0.U
+}
+
+class VGADisplay extends Module {
+  val io = IO(new Bundle() {
+    val x = Output(UInt(16.W))
+    val y = Output(UInt(16.W))
+    val video_on = Output(Bool())
+
+    val hsync = Output(Bool())
+    val vsync = Output(Bool())
+  })
+
+  val sync = Module(new VGASync)
+  io.hsync := sync.io.hsync
+  io.vsync := sync.io.vsync
+  io.x := sync.io.x
+  io.y := sync.io.y
+  io.video_on := sync.io.y
+}