path: root/src/test/scala/chiselTests/Mem.scala

// SPDX-License-Identifier: Apache-2.0

package chiselTests

import chisel3._
import chisel3.stage.ChiselStage
import chisel3.util._
import chisel3.testers.BasicTester

class MemVecTester extends BasicTester {
  val mem = Mem(2, Vec(2, UInt(8.W)))

  // Circuit style tester is definitely the wrong abstraction here
  val (cnt, wrap) = Counter(true.B, 2)
  mem(0)(0) := 1.U

  when(cnt === 1.U) {
    assert(mem.read(0.U)(0) === 1.U)
    stop()
  }
}

class SyncReadMemTester extends BasicTester {
  val (cnt, _) = Counter(true.B, 5)
  val mem = SyncReadMem(2, UInt(2.W))
  val rdata = mem.read(cnt - 1.U, cnt =/= 0.U)

  switch(cnt) {
    is(0.U) { mem.write(cnt, 3.U) }
    is(1.U) { mem.write(cnt, 2.U) }
    is(2.U) { assert(rdata === 3.U) }
    is(3.U) { assert(rdata === 2.U) }
    is(4.U) { stop() }
  }
}

class SyncReadMemWriteCollisionTester extends BasicTester {
  val (cnt, _) = Counter(true.B, 5)

  // Write-first
  val m0 = SyncReadMem(2, UInt(2.W), SyncReadMem.WriteFirst)
  val rd0 = m0.read(cnt)
  m0.write(cnt, cnt)

  // Read-first
  val m1 = SyncReadMem(2, UInt(2.W), SyncReadMem.ReadFirst)
  val rd1 = m1.read(cnt)
  m1.write(cnt, cnt)

  // Read data from address 0
  when(cnt === 3.U) {
    assert(rd0 === 2.U)
    assert(rd1 === 0.U)
  }

  when(cnt === 4.U) {
    stop()
  }
}

class SyncReadMemWithZeroWidthTester extends BasicTester {
  val (cnt, _) = Counter(true.B, 3)
  val mem = SyncReadMem(2, UInt(0.W))
  val rdata = mem.read(0.U, true.B)

  switch(cnt) {
    is(1.U) { assert(rdata === 0.U) }
    is(2.U) { stop() }
  }
}

// TODO this can't actually simulate with FIRRTL behavioral mems
class HugeSMemTester(size: BigInt) extends BasicTester {
  val (cnt, _) = Counter(true.B, 5)
  val mem = SyncReadMem(size, UInt(8.W))
  val rdata = mem.read(cnt - 1.U, cnt =/= 0.U)

  switch(cnt) {
    is(0.U) { mem.write(cnt, 3.U) }
    is(1.U) { mem.write(cnt, 2.U) }
    is(2.U) { assert(rdata === 3.U) }
    is(3.U) { assert(rdata === 2.U) }
    is(4.U) { stop() }
  }
}
class HugeCMemTester(size: BigInt) extends BasicTester {
  val (cnt, _) = Counter(true.B, 5)
  val mem = Mem(size, UInt(8.W))
  val rdata = mem.read(cnt)

  switch(cnt) {
    is(0.U) { mem.write(cnt, 3.U) }
    is(1.U) { mem.write(cnt, 2.U) }
    is(2.U) { assert(rdata === 3.U) }
    is(3.U) { assert(rdata === 2.U) }
    is(4.U) { stop() }
  }
}

class SyncReadMemBundleTester extends BasicTester {
  val (cnt, _) = Counter(true.B, 5)
  val tpe = new Bundle {
    val foo = UInt(2.W)
  }
  val mem = SyncReadMem(2, tpe)
  val rdata = mem.read(cnt - 1.U, cnt =/= 0.U)

  switch(cnt) {
    is(0.U) {
      val w = Wire(tpe)
      w.foo := 3.U
      mem.write(cnt, w)
    }
    is(1.U) {
      val w = Wire(tpe)
      w.foo := 2.U
      mem.write(cnt, w)
    }
    is(2.U) { assert(rdata.foo === 3.U) }
    is(3.U) { assert(rdata.foo === 2.U) }
    is(4.U) { stop() }
  }
}

class MemBundleTester extends BasicTester {
  val tpe = new Bundle {
    val foo = UInt(2.W)
  }
  val mem = Mem(2, tpe)

  // Circuit style tester is definitely the wrong abstraction here
  val (cnt, wrap) = Counter(true.B, 2)
  mem(0) := {
    val w = Wire(tpe)
    w.foo := 1.U
    w
  }

  when(cnt === 1.U) {
    assert(mem.read(0.U).foo === 1.U)
    stop()
  }
}

private class TrueDualPortMemoryIO(val addrW: Int, val dataW: Int) extends Bundle {
  require(addrW > 0, "address width must be greater than 0")
  require(dataW > 0, "data width must be greater than 0")

  val clka = Input(Clock())
  val ena = Input(Bool())
  val wea = Input(Bool())
  val addra = Input(UInt(addrW.W))
  val dia = Input(UInt(dataW.W))
  val doa = Output(UInt(dataW.W))

  val clkb = Input(Clock())
  val enb = Input(Bool())
  val web = Input(Bool())
  val addrb = Input(UInt(addrW.W))
  val dib = Input(UInt(dataW.W))
  val dob = Output(UInt(dataW.W))
}

private class TrueDualPortMemory(addrW: Int, dataW: Int) extends RawModule {
  val io = IO(new TrueDualPortMemoryIO(addrW, dataW))
  val ram = SyncReadMem(1 << addrW, UInt(dataW.W))

  // Port a
  withClock(io.clka) {
    io.doa := DontCare
    when(io.ena) {
      when(io.wea) {
        ram(io.addra) := io.dia
      }
      io.doa := ram(io.addra)
    }
  }

  // Port b
  withClock(io.clkb) {
    io.dob := DontCare
    when(io.enb) {
      when(io.web) {
        ram(io.addrb) := io.dib
      }
      io.dob := ram(io.addrb)
    }
  }
}

class MemorySpec extends ChiselPropSpec {
  property("Mem of Vec should work") {
    assertTesterPasses { new MemVecTester }
  }

  property("SyncReadMem should work") {
    assertTesterPasses { new SyncReadMemTester }
  }

  property("SyncReadMems of Bundles should work") {
    assertTesterPasses { new SyncReadMemBundleTester }
  }

  property("Mems of Bundles should work") {
    assertTesterPasses { new MemBundleTester }
  }

  property("SyncReadMem write collision behaviors should work") {
    assertTesterPasses { new SyncReadMemWriteCollisionTester }
  }

  property("SyncReadMem should work with zero width entry") {
    assertTesterPasses { new SyncReadMemWithZeroWidthTester }
  }

  property("Massive memories should be emitted in Verilog") {
    val addrWidth = 65
    val size = BigInt(1) << addrWidth
    val smem = compile(new HugeSMemTester(size))
    smem should include(s"reg /* sparse */ [7:0] mem [0:$addrWidth'd${size - 1}];")
    val cmem = compile(new HugeCMemTester(size))
    cmem should include(s"reg /* sparse */ [7:0] mem [0:$addrWidth'd${size - 1}];")
  }

  property("Implicit conversions with Mem indices should work") {
    """
      |import chisel3._
      |import chisel3.util.ImplicitConversions._
      |class MyModule extends Module {
      |  val io = IO(new Bundle {})
      |  val mem = Mem(32, UInt(8.W))
      |  mem(0) := 0.U
      |}
      |""".stripMargin should compile
  }

  property("memories in modules without implicit clock should compile without warning or error") {
    val stage = new ChiselStage
    stage.emitVerilog(new TrueDualPortMemory(4, 32))
  }
}