riscv/devices.cc

   1 #include "devices.h"
   2
   3 void bus_t::add_device(reg_t addr, abstract_device_t* dev)
   4 {
   5   // Searching devices via lower_bound/upper_bound
   6   // implicitly relies on the underlying std::map
   7   // container to sort the keys and provide ordered
   8   // iteration over this sort, which it does. (python's
   9   // SortedDict is a good analogy)
  10   devices[addr] = dev;
  11 }
  12
  13 bool bus_t::load(reg_t addr, size_t len, uint8_t* bytes)
  14 {
  15   // Find the device with the base address closest to but
  16   // less than addr (price-is-right search)
  17   auto it = devices.upper_bound(addr);
  18   if (devices.empty() || it == devices.begin()) {
  19     // Either the bus is empty, or there weren't
  20     // any items with a base address <= addr
  21     return false;
  22   }
  23   // Found at least one item with base address <= addr
  24   // The iterator points to the device after this, so
  25   // go back by one item.
  26   it--;
  27   return it->second->load(addr - it->first, len, bytes);
  28 }
  29
  30 bool bus_t::store(reg_t addr, size_t len, const uint8_t* bytes)
  31 {
  32   // See comments in bus_t::load
  33   auto it = devices.upper_bound(addr);
  34   if (devices.empty() || it == devices.begin()) {
  35     return false;
  36   }
  37   it--;
  38   return it->second->store(addr - it->first, len, bytes);
  39 }
  40
  41 std::pair<reg_t, abstract_device_t*> bus_t::find_device(reg_t addr)
  42 {
  43   // See comments in bus_t::load
  44   auto it = devices.upper_bound(addr);
  45   if (devices.empty() || it == devices.begin()) {
  46     return std::make_pair((reg_t)0, (abstract_device_t*)NULL);
  47   }
  48   it--;
  49   return std::make_pair(it->first, it->second);
  50 }