/*******************************************************************************
 HARPtools by Chad D. Kersey, Summer 2011
*******************************************************************************/
#include <fstream>
#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <stdlib.h>
#include <pthread.h>

#include "include/debug.h"
#include "include/types.h"
#include "include/util.h"
#include "include/mem.h"
#include "include/core.h"

using namespace std;
using namespace Harp;

RamMemDevice::RamMemDevice(const char *filename, Size wordSize) :
  wordSize(wordSize), contents()
{
  ifstream input(filename);

  if (!input) {
    cout << "Error reading file \"" << filename << "\" into RamMemDevice.\n";
    exit(1);
  }

  do { contents.push_back(input.get()); } while (input);

  while (contents.size() % wordSize) contents.push_back(0x00);
}

RamMemDevice::RamMemDevice(Size size, Size wordSize) : 
  contents(size), wordSize(wordSize) {}

void RomMemDevice::write(Addr, Word) {
  cout << "Attempt to write to ROM.\n";
  exit(1);
}

Word RamMemDevice::read(Addr addr) {
  D(2, "RAM read, addr=0x" << hex << addr);
  Word w = readWord(contents, addr, wordSize - addr%wordSize);
  return w;
}

void RamMemDevice::write(Addr addr, Word w) {
  D(2, "RAM write, addr=0x" << hex << addr);
  writeWord(contents, addr, wordSize - addr%wordSize, w);
}

MemDevice &MemoryUnit::ADecoder::doLookup(Addr a, Size &bit) {
  if (range == 0 || (a&((1ll<<bit)-1)) >= range) {
    ADecoder *p(((a>>bit)&1)?oneChild:zeroChild);
    if (p) { bit--; return p->doLookup(a, bit); }
    else {cout << "lookup of 0x" << hex << a << " failed.\n";
          throw BadAddress();}
  } else {
    return *md;
  }
}

void MemoryUnit::ADecoder::map(Addr a, MemDevice &m, Size r, Size bit)
{
  if ((1llu << bit) <= r) {
    md = &m;
    range = m.size();
  } else {
    ADecoder *&child(((a>>bit)&1)?oneChild:zeroChild);
    if (!child) child = new ADecoder();
    child->map(a, m, r, bit-1);
  }
}

Byte *MemoryUnit::ADecoder::getPtr(Addr a, Size sz, Size wordSize) {
  Size bit = wordSize - 1;
  MemDevice &m(doLookup(a, bit));
  a &= (2<<bit)-1;
  if (a + sz <= m.size()) return m.base() + a;
  return NULL;
}

Word MemoryUnit::ADecoder::read(Addr a, bool sup, Size wordSize) {
  Size bit = wordSize - 1;
  MemDevice &m(doLookup(a, bit));
  a &= (2<<bit)-1;
  // std::cout << std::hex << "ADecoder::read(Addr " << a << ", sup " << sup << ", wordSize " << wordSize << " -> ";
  // std::cout << "Data: " << m.read(a) << "\n";
  return m.read(a);
}

void MemoryUnit::ADecoder::write(Addr a, Word w, bool sup, Size wordSize) {
  Size bit = wordSize - 1;
  MemDevice &m(doLookup(a, bit));

  RAM & r = (RAM &) m;
  // a &= (2<<bit)-1;
  // std::cout << std::hex << "ADecoder::write(Addr " << a << ", w " << w << ", sup " << sup << ", wordSize " << wordSize << "\n";
  Word before = m.read(a);
  Word new_word = w;

  if (a == 0x8000012c)
  {
    printf("WRITING TO 0x8000012c -> %d\n", w);
  }

  if (wordSize == 8)
  {
    r.writeByte(a, &w);
  }
  else if (wordSize == 16)
  {
    r.writeHalf(a, &w);
  }
  else
  {
    r.writeWord(a, &w);
  }
  // m.write(a, new_word);
}

Byte *MemoryUnit::getPtr(Addr a, Size s) {
  return ad.getPtr(a, s, addrBytes*8);
}

void MemoryUnit::attach(MemDevice &m, Addr base) {
  ad.map(base, m, m.size(), addrBytes*8 - 1);
}

MemoryUnit::TLBEntry MemoryUnit::tlbLookup(Addr vAddr, Word flagMask) {
  map<Addr, MemoryUnit::TLBEntry>::iterator i;
  if ((i = tlb.find(vAddr/pageSize)) != tlb.end()) {
    TLBEntry &t = i->second;
    if (t.flags & flagMask) return t;
    else {
      D(2, "Page fault on addr 0x" << hex << vAddr << "(bad flags)");
      throw PageFault(vAddr, false);
    }
  } else {
    D(2, "Page fault on addr 0x" << hex << vAddr << "(not in TLB)");
    throw PageFault(vAddr, true);
  }
}

#ifdef EMU_INSTRUMENTATION
Addr MemoryUnit::virtToPhys(Addr vAddr) {
  TLBEntry t = tlbLookup(vAddr, 077);
  return t.pfn*pageSize + vAddr%pageSize;
}
#endif

Word MemoryUnit::read(Addr vAddr, bool sup) {
  Addr pAddr;
  if (disableVm) {
    pAddr = vAddr;
  } else {
    Word flagMask = sup?8:1;
    TLBEntry t = tlbLookup(vAddr, flagMask);
    pAddr = t.pfn*pageSize + vAddr%pageSize;
  }
  // std::cout << "MU::write: About to read: " << std::hex << pAddr << " = " << (ad.read(pAddr, sup, 8*addrBytes)) << " with " << std::dec << (8*addrBytes) << "\n";
  return ad.read(pAddr, sup, 8*addrBytes);
}

Word MemoryUnit::fetch(Addr vAddr, bool sup) {
  Addr pAddr;

  if (disableVm) {
    pAddr = vAddr;
  } else {
    Word flagMask = sup?32:4;
    TLBEntry t = tlbLookup(vAddr, flagMask);
    pAddr = t.pfn*pageSize + vAddr%pageSize;
  }

  Word instruction = ad.read(pAddr, sup, 8*addrBytes);

  return instruction;
}

void MemoryUnit::write(Addr vAddr, Word w, bool sup, Size bytes) {
  Addr pAddr;

  if (disableVm) {
    pAddr = vAddr;
  } else {
    Word flagMask = sup?16:2;
    TLBEntry t = tlbLookup(vAddr, flagMask);
    pAddr = t.pfn*pageSize + vAddr%pageSize;
  }
  // std::cout << "MU::write: About to write: " << std::hex << pAddr << " = " << w << " with " << std::dec << 8*bytes << "\n";
  ad.write(pAddr, w, sup, 8*bytes);
  // std::cout << std::hex << "reading same address: " << (this->read(vAddr, sup)) << "\n";
}

void MemoryUnit::tlbAdd(Addr virt, Addr phys, Word flags) {
  D(1, "tlbAdd(0x" << hex << virt << ", 0x" << phys << ", 0x" << flags << ')');
  tlb[virt/pageSize] = TLBEntry(phys/pageSize, flags);
}

void MemoryUnit::tlbRm(Addr va) {
  if (tlb.find(va/pageSize) != tlb.end()) tlb.erase(tlb.find(va/pageSize));
}

void *Harp::consoleInputThread(void* arg_vp) {
  ConsoleMemDevice *arg = (ConsoleMemDevice *)arg_vp;
  char c;
  while (cin) {
    c = cin.get();
    pthread_mutex_lock(&arg->cBufLock);
    arg->cBuf.push(c);
    pthread_mutex_unlock(&arg->cBufLock);
  }
  cout << "Console input ended. Exiting.\n";
  exit(4);
}

ConsoleMemDevice::ConsoleMemDevice(Size wS, std::ostream &o, Core &core,
                                   bool batch) : 
  wordSize(wS), output(o), core(core), cBuf()
{
  // Create a console input thread if we are running in interactive mode.
  if (!batch) {
    pthread_t *thread = new pthread_t;
    pthread_create(thread, NULL, consoleInputThread, (void*)this);
  }
  pthread_mutex_init(&cBufLock, NULL);
}

void ConsoleMemDevice::poll() {
  pthread_mutex_lock(&cBufLock);
  if (!cBuf.empty()) core.interrupt(8);
  pthread_mutex_unlock(&cBufLock);
}

Word DiskControllerMemDevice::read(Addr a) {
  switch (a/8) {
    case 0: return curDisk;
    case 1: return curBlock;
    case 2: return disks[curDisk].blocks * blockSize;
    case 3: return physAddr;
    case 4: return command;
    case 5: return status;
    default:
      cout << "Attempt to read invalid disk controller register.\n";
      exit(1);
  }
}

void DiskControllerMemDevice::write(Addr a, Word w) {
  switch (a/8) {
    case 0: if (w <= disks.size()) {
              curDisk = w;
              status = OK;
            } else {
              status = INVALID_DISK;
            }
            break;
    case 1: if (w < disks[curDisk].blocks) {
              curBlock = w;
            } else {
              status = INVALID_BLOCK;
            }
            break;
    case 2: nBlocks = w >= disks[curDisk].blocks?disks[curDisk].blocks - 1 : w;
            status = OK;
            break;
    case 3: physAddr = w;
            status = OK;
            break;
    case 4: if (w == 0) {
            } else {
            }
            cout << "TODO: Implement disk read and write!\n";
            break;
  }
}