Merge pull request #9 from weijiew/lab8-plic

add plic and tests.

CMakeLists.txt

@@ -21,6 +21,8 @@ set(COMMON_SOURCES
         src/csr.cpp
         src/exception.cpp
         src/exception.h
+        src/plic.cpp
+        src/plic.h
 )
 
 add_library(common_library ${COMMON_SOURCES})
@@ -46,6 +48,7 @@ add_executable(unit_test
         tests/unitest/cpu_test.cpp
         tests/unitest/csr_test.cpp
         tests/unitest/exception.cpp
+        tests/unitest/plic_test.cpp
 )
 
 # 将库链接到 unit_test 可执行文件

src/param.h

@@ -85,4 +85,26 @@ constexpr Mode Supervisor = 0b01;
 // 定义 Machine 模式，二进制表示为 11
 constexpr Mode Machine = 0b11;
 
+// PLIC的基地址，所有的PLIC寄存器都从这个地址开始映射到内存中。
+constexpr uint64_t PLIC_BASE = 0xc000000;
+
+// PLIC的大小，表示PLIC寄存器在内存中的映射区域的大小。这个大小是0x4000000。
+constexpr uint64_t PLIC_SIZE = 0x4000000;
+
+// PLIC的结束地址，表示PLIC寄存器在内存中的映射区域的结束地址。
+constexpr uint64_t PLIC_END = PLIC_BASE + PLIC_SIZE - 1;
+
+// PLIC的挂起寄存器的地址，当有中断挂起时，对应的位会被设置为1。
+constexpr uint64_t PLIC_PENDING = PLIC_BASE + 0x1000;
+
+// PLIC的使能寄存器的地址，可以通过设置这个寄存器来使能或禁止中断。
+constexpr uint64_t PLIC_SENABLE = PLIC_BASE + 0x2000;
+
+// PLIC的优先级寄存器的地址，可以通过设置这个寄存器来改变中断的优先级。
+constexpr uint64_t PLIC_SPRIORITY = PLIC_BASE + 0x201000;
+
+// PLIC的确认寄存器的地址，当处理器处理完一个中断后，
+// 会写这个寄存器来通知PLIC中断已经被处理。
+constexpr uint64_t PLIC_SCLAIM = PLIC_BASE + 0x201004;
+
 }

src/plic.cpp

@@ -0,0 +1,54 @@
+//
+// Created by Jie Wei on 2024/4/2.
+//
+
+#include <cstdint>
+#include "exception.h"
+#include "plic.h"
+#include "param.h"
+
+namespace crvemu {
+
+uint64_t Plic::load(uint64_t addr, uint64_t size) {
+  if (size != 32) {
+    throw Exception(ExceptionType::LoadAccessFault, addr);
+  }
+  switch (addr) {
+    case PLIC_PENDING:
+      return pending;
+    case PLIC_SENABLE:
+      return senable;
+    case PLIC_SPRIORITY:
+      return spriority;
+    case PLIC_SCLAIM:
+      return sclaim;
+    default:
+      return 0;
+  }
+}
+
+
+void Plic::store(uint64_t addr, uint64_t size, uint64_t value) {
+  if (size != 32) {
+    throw Exception(ExceptionType::StoreAMOAccessFault, addr);
+  }
+  switch (addr) {
+    case PLIC_PENDING:
+      pending = value;
+      break;
+    case PLIC_SENABLE:
+      senable = value;
+      break;
+    case PLIC_SPRIORITY:
+      spriority = value;
+      break;
+    case PLIC_SCLAIM:
+      sclaim = value;
+      break;
+    default:
+      break;
+  }
+}
+
+}
+

src/plic.h

@@ -0,0 +1,29 @@
+//
+// Created by Jie Wei on 2024/4/2.
+//
+
+#pragma once
+#include <cstdint>
+#include "exception.h"
+
+namespace crvemu {
+
+// 这个类的设计是为了模拟PLIC的功能，使得在模拟器中可以像在真实硬件中一样处理中断。
+// 这个类的方法提供了对PLIC寄存器的读写操作，这些操作在处理中断时是必需的。
+class Plic {
+ public:
+  Plic() : pending(0), senable(0), spriority(0), sclaim(0) {}
+
+  // 读取和写入PLIC的寄存器
+  uint64_t load(uint64_t addr, uint64_t size);
+  void store(uint64_t addr, uint64_t size, uint64_t value);
+
+ private:
+  uint64_t pending;     // 对应PLIC的挂起寄存器
+  uint64_t senable;     // 对应PLIC的使能寄存器
+  uint64_t spriority;   // 对应PLIC的优先级寄存器
+  uint64_t sclaim;      // 对应PLIC的索引寄存器
+};
+
+}
+

tests/unitest/plic_test.cpp

@@ -0,0 +1,63 @@
+//
+// Created by Jie Wei on 2024/4/2.
+//
+
+#include "gtest/gtest.h"
+#include "../../src/plic.h"
+#include "../../src/param.h"
+
+namespace crvemu {
+
+class PlicTest : public ::testing::Test {
+ protected:
+  Plic plic;
+};
+
+TEST_F(PlicTest, LoadStoreTest) {
+  uint64_t test_value = 123;
+
+  // Test store and load for each register
+  plic.store(PLIC_PENDING, 32, test_value);
+  EXPECT_EQ(plic.load(PLIC_PENDING, 32), test_value);
+
+  plic.store(PLIC_SENABLE, 32, test_value);
+  EXPECT_EQ(plic.load(PLIC_SENABLE, 32), test_value);
+
+  plic.store(PLIC_SPRIORITY, 32, test_value);
+  EXPECT_EQ(plic.load(PLIC_SPRIORITY, 32), test_value);
+
+  plic.store(PLIC_SCLAIM, 32, test_value);
+  EXPECT_EQ(plic.load(PLIC_SCLAIM, 32), test_value);
+}
+
+// Test exception throwing when size is not 32
+TEST_F(PlicTest, ExceptionTest) {
+  EXPECT_THROW(plic.load(PLIC_PENDING, 64), Exception);
+  EXPECT_THROW(plic.store(PLIC_PENDING, 64, 123), Exception);
+}
+
+// 测试未知寄存器地址的行为
+TEST_F(PlicTest, UnknownAddressTest) {
+  uint64_t unknown_address = 0xdeadbeef;
+  EXPECT_NO_THROW(plic.store(unknown_address, 32, 123));
+  EXPECT_EQ(plic.load(unknown_address, 32), 0);
+}
+
+//// 测试处理多个中断请求的行为
+//TEST_F(PlicTest, MultipleInterruptsTest) {
+//  plic.store(PLIC_PENDING, 32, 1);
+//  plic.store(PLIC_PENDING, 32, 2);
+//  EXPECT_EQ(plic.load(PLIC_SCLAIM, 32), 1);
+//  EXPECT_EQ(plic.load(PLIC_SCLAIM, 32), 2);
+//}
+
+//// 测试处理优先级不同的中断请求的行为
+//TEST_F(PlicTest, PriorityTest) {
+//  plic.store(PLIC_PENDING, 32, 1);
+//  plic.store(PLIC_SPRIORITY, 32, 1);
+//  plic.store(PLIC_PENDING, 32, 2);
+//  plic.store(PLIC_SPRIORITY, 32, 2);
+//  EXPECT_EQ(plic.load(PLIC_SCLAIM, 32), 2);
+//  EXPECT_EQ(plic.load(PLIC_SCLAIM, 32), 1);
+//}
+}  // namespace crvemu