From 18562524bdefe7b94e28d752a0d2d1dac542cc33 Mon Sep 17 00:00:00 2001
From: zhangzifei <1773908404@qq.com>
Date: Wed, 2 Oct 2019 16:13:37 +0800
Subject: [PATCH] commit for add new brach. need add mem path for ptw

---
 src/main/scala/noop/TLB.scala | 49 +++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 src/main/scala/noop/TLB.scala

diff --git a/src/main/scala/noop/TLB.scala b/src/main/scala/noop/TLB.scala
new file mode 100644
index 000000000..af17ea173
--- /dev/null
+++ b/src/main/scala/noop/TLB.scala
@@ -0,0 +1,49 @@
+package noop
+
+import chisel3._
+import chisel3.util._
+import chisel3.util.experimental.BoringUtils
+
+import bus.simplebus._
+import bus.axi4._
+import utils._
+
+//no details about tlb of riscv32 is found. So just do as wanted
+//only find instruction SFENCE.VMA(Supervisor fence. vma
+//in mips, there is an MASK reg which control the page size. just ignore it and have 4KB for deault 
+//mips gs132:
+//| EntryHi     | PageMask |    |   EntryLo0   |   EntryLo1   |
+//| VPN2 | ASID | PageMask | G  | PFN0 | C/D/V | PFN1 | C/D/V |
+//| 19b  | 8b   | 12b      | 1b | 20b  | 5b    | 20b  | 5b    |
+
+//fist step, the tlb only have one 
+//riscv32 tlb:
+//| VPN | ASID |  G  | PFN | D/A/U/X/W/R/V |
+//| 20b | 9b   |  1b | 22b | 7b            |
+
+trait tlbSv32Const {
+  val debug = false
+
+  val numEntry = 1
+  
+  val PPN1Len = 12
+  val PPN0Len = 10
+  val PageSizeLen = 12
+
+  def tlbBundle = new Bundle {
+    val VPN  = UInt(20.W)
+    val ASID = UInt(9.W)
+    val G    = UInt(1.W)
+    val PFN  = UInt(22.W)
+    val D    = UInt(1.W)
+    val A    = UInt(1.W)
+    val U    = UInt(1.W)
+    val X    = UInt(1.W)
+    val W    = UInt(1.W)
+    val R    = UInt(1.W)
+    val V    = UInt(1.W)
+  }
+}
+
+
+
-- 
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