Add debug_module bus device.

This should replace the ROM hack I implemented earlier, but for now both
exist together.

Back to the point where gdb connects, core jumps to ROM->RAM->ROM.

1 files changed, 6 insertions, 0 deletions

diff --git a/riscv/devices.h b/riscv/devices.h
index cb3b6d9..8378188 100644
--- a/riscv/devices.h
+++ b/riscv/devices.h
@@ -11,6 +11,9 @@ class abstract_device_t {
  public:
   virtual bool load(reg_t addr, size_t len, uint8_t* bytes) = 0;
   virtual bool store(reg_t addr, size_t len, const uint8_t* bytes) = 0;
+  // Return a pointer to the start of the page that addr falls in, or NULL if
+  // there is no IO device at that address.
+  virtual char* page(reg_t addr) { return NULL; }
   virtual ~abstract_device_t() {}
 };
 
@@ -18,6 +21,9 @@ class bus_t : public abstract_device_t {
  public:
   bool load(reg_t addr, size_t len, uint8_t* bytes);
   bool store(reg_t addr, size_t len, const uint8_t* bytes);
+  // Return a pointer to the start of the page that addr falls in, or NULL if
+  // there is no IO device at that address.
+  char* page(reg_t paddr);
   void add_device(reg_t addr, abstract_device_t* dev);
 
  private: