mem.cpp

#include <iostream>
#include <stdio.h>

#include "mem.h"

// NOTE : the way 8 and 16 bits access were implemented naturally prevent misaligned accesses

// TODO : write an exeption handler for memory violations (and other unsupported events ?)
// - dump memory address, PC value, instruction details, register status
// - and exit... or just display a nice blue screen and reboot ?



Mem::Mem() {
  ram16 = (int16_t*)*(&ram8);
  ram32 = (int32_t*)*(&ram8);
}

Mem::~Mem() {
  // nothing to dealocate
}

uint32_t Mem::getRamStartAddress() {
  return ramStartAddress;
}

void Mem::setRamStartAddress(uint32_t address) {
  ramStartAddress = address;
}

int8_t Mem::get8(uint32_t address) {
  if (address == GETCHAR)
    return (int8_t)getchar();

  address -= ramStartAddress;
  if (address < RAMSIZE)
    return ram8[address];
  else {
    std::cerr << "\n\nIllegal Memory Read\n\n";
    return 0;
  }
}

int16_t Mem::get16(uint32_t address) {
  if (address == GETCHAR)
    return (int16_t)getchar();

  address -= ramStartAddress;
  if (address < RAMSIZE)
    return ram16[address >> 1];
  else {
    std::cerr << "\n\nIllegal Memory Read\n\n";
    return 0;
  }
}

int32_t Mem::get32(uint32_t address) {
  if (address == GETCHAR)
    return (int32_t)getchar();

  address -= ramStartAddress;
  if (address < RAMSIZE)
    return ram32[address >> 2];
  else {
    std::cerr << "\n\nIllegal Memory Read\n\n";
    return 0;
  }
}



void Mem::set8(uint32_t address, int8_t value) {
  if (address == PUTCHAR) {
    putchar((char)value);
  }
  else {
    address -= ramStartAddress;
    if (address < RAMSIZE)
      ram8[address] = value;
    else
      std::cerr << "\n\nIllegal Memory Write\n\n";
  }
}

void Mem::set16(uint32_t address, int16_t value) {
  if (address == PUTCHAR) {
    putchar((char)value);
  }
  else {
    address -= ramStartAddress;
    if (address < RAMSIZE)
      ram16[address >> 1] = value;
    else
      std::cerr << "\n\nIllegal Memory Write\n\n";
  }
}

void Mem::set32(uint32_t address, int32_t value) {
  if (address == PUTCHAR) {
    putchar((char)value);
  }
  else {
    address -= ramStartAddress;
    if (address < RAMSIZE)
      ram32[address >> 2] = value;
    else
      std::cerr << "\n\nIllegal Memory Write\n\n";
  }
}