import MemoryAccessException
 
class Mem():
 
    def __init__(self):
        self.mem = [0xCD] * 2**14   # Generic Memory
 
    def write8(self, addr, val):
        assert val >= 0 and val <= 0xFF, "Memory Assertion Byte out of range addr %x val %x" % (addr, val)
        self.mem[addr] = val
 
    def read8(self, addr):
        return self.mem[addr]
 
    def write16(self, addr, val):
 
        if (addr & 0x01) != 0:
            raise MemoryAccessException
 
        self.write8(addr, val >> 8)
        self.write8(addr+1, val)
 
    def read16(self, addr):
        val =  self.read8(addr) << 8
        val |= self.read8(addr+1)
        return val
 
 
    def write32(self, addr, val):
        if (addr & 0x03) != 0:
            raise MemoryAccessException
        # Big endien mem org
        self.write8(addr,   val >> 24)
        self.write8(addr+1, val >> 16)
        self.write8(addr+2, val >> 8)
        self.write8(addr+3, val)
 
 
    def read32(self, addr):
        val =  self.read8(addr)   << 24
        val |= self.read8(addr+1) << 16
        val |= self.read8(addr+2) << 8
        val |= self.read8(addr+3)
        return val
 
    def writeWord(self, addr, val):
        self.write32(addr, val)