npc: wip, cannot build

npc/csrc/devices/include/devices.hpp

@@ -0,0 +1,85 @@
+#include <array>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <initializer_list>
+#include <iostream>
+#include <iterator>
+#include <map>
+#include <memory>
+#include <unordered_map>
+#include <utility>
+
+namespace Devices {
+class Device {
+public:
+  uint8_t *p_buf;
+  uint64_t addr;
+  size_t len;
+  Device(uint64_t addr, size_t len, uint8_t buf[])
+      : addr(addr), len(len), p_buf(buf) {}
+  virtual ~Device(){};
+  virtual void io_handler(uint32_t offset, size_t len, bool is_write) = 0;
+  void transfer(uint8_t *src, size_t len, bool is_write) {
+    if (is_write) {
+      memmove(p_buf, src, len);
+    } else {
+      memmove(src, p_buf, len);
+    }
+  };
+};
+
+class Serial : public Device {
+  uint8_t buf[1];
+
+public:
+  Serial(uint64_t addr, size_t len);
+  ~Serial() override{};
+  void io_handler(uint32_t offset, size_t len, bool is_write) override;
+  // void transfer(uint8_t *src, size_t len, bool is_write) override;
+};
+
+class RTC : public Device {
+  uint8_t buf[8];
+  uint64_t boot_time;
+  uint64_t get_time_internal();
+  uint64_t get_time();
+
+public:
+  RTC(uint64_t addr, size_t len);
+  ~RTC() override{};
+  void io_handler(uint32_t offset, size_t len, bool is_write) override;
+  // void transfer(uint8_t *src, size_t len, bool is_write) override;
+};
+
+class DeviceMap {
+  std::map<uint64_t, Device *> addr_to_device;
+
+public:
+  DeviceMap(std::initializer_list<Device *> devices) {
+    for (auto device : devices) {
+      addr_to_device.insert(std::make_pair(device->addr, device));
+    }
+  }
+  bool handle(uint64_t addr, uint8_t *data, size_t len, bool is_write) {
+    auto it = addr_to_device.upper_bound(addr);
+    if (it == addr_to_device.begin() ||
+        (--it)->second->addr + it->second->len <= addr) {
+      std::cerr << "Use of a unintialized device at memory addr: 0x" << std::hex
+                << addr << std::dec << std::endl;
+      return false;
+    }
+    auto &device = it->second;
+    uint32_t offset = addr - device->addr;
+    if (is_write) {
+      device->transfer(data, len, is_write);
+      device->io_handler(offset, len, is_write);
+    } else {
+      device->io_handler(offset, len, is_write);
+      device->transfer(data, len, is_write);
+    }
+    return true;
+  }
+};
+} // namespace Devices