cache.py

import math

def get_direct_mapped_address(line_size, entry_size, address_str):
  # オフセットのサイズを求める
  offset_size = int(math.log2(line_size))
  # インデックスのサイズを求める
  index_size = int(math.log2(entry_size))

  print("offset:", offset_size, "bit")
  print("index: ", index_size, "bit")

  offset_byte = address_str[len(address_str)-offset_size:]
  index_byte = address_str[len(address_str)-offset_size-index_size:len(address_str)-offset_size]
  tag_byte = address_str[:len(address_str)-offset_size-index_size]

  print("offset byte: ", offset_byte, hex(int(offset_byte, 2)))
  print("index byte:  ", index_byte, hex(int(index_byte, 2)))
  print("tag_byte:    ", tag_byte, hex(int(tag_byte, 2)))

  return (offset_byte, index_byte, tag_byte)

def get_nway_setassociative_address(way, line_size, entry_size, address_str):
  # オフセットのサイズを求める
  offset_size = int(math.log2(line_size))
  # インデックスのサイズを求める
  index_size = int(math.log2(entry_size)-int(math.log2(way))) # n wayなので最初の log2(n) ビットが不要

  print("offset:", offset_size, "bit")
  print("index: ", index_size, "bit")

  offset_byte = address_str[len(address_str)-offset_size:]
  index_byte = address_str[len(address_str)-offset_size-index_size:len(address_str)-offset_size]
  tag_byte = address_str[:len(address_str)-offset_size-index_size]

  print("offset byte: ", offset_byte, hex(int(offset_byte, 2)))
  print("index byte:  ", index_byte, hex(int(index_byte, 2)))
  print("tag_byte:    ", tag_byte, hex(int(tag_byte, 2)))

  return (offset_byte, index_byte, tag_byte)

def get_fully_associative_address(line_size, entry_size, address_str):
  # オフセットのサイズを求める
  offset_size = int(math.log2(line_size))

  print("offset:", offset_size, "bit")
  print("index: ", "0 bit")

  offset_byte = address_str[len(address_str)-offset_size:]
  tag_byte = address_str[:len(address_str)-offset_size]

  print("offset byte: ", offset_byte, hex(int(offset_byte, 2)))
  print("index byte:  ", "N/A", "N/A")
  print("tag_byte:    ", tag_byte, hex(int(tag_byte, 2)))

  return (offset_byte, 0, tag_byte)


if __name__ == "__main__":
  line_size = 16 # bytes
  entry_size = 128
  address = bin(0x7a14)
  way = 2

  address_str = str(address)[2:]
  print(address_str)
  
  print("\ndirect mapped")
  get_direct_mapped_address(line_size, entry_size, address_str)
  print("\n{}-way setassociative".format(way))
  get_nway_setassociative_address(way, line_size, entry_size, address_str)
  print("\nfully associative")
  get_fully_associative_address(line_size, entry_size, address_str)