Final answer:
The claim is false; shifting a number right two bits converts word level to byte level addressing by dividing by 4, but you don't fill in with zeros on the left, the fill is determined by the sign bit or is zero for unsigned values.
Step-by-step explanation:
The statement that to convert a field in an instruction that represents a number of machine words to byte level addressing you need to shift the number right two bits and fill in with zeros on the left is false. In a typical computer system where a machine word is assumed to be 4 bytes (32 bits), shifting a value to the right by two bits actually divides the number by 4, which would convert word level addressing to byte level addressing. However, one does not fill in with zeros on the left; rather, the fill depends on the original number's sign bit (in signed representations) or is simply zero for unsigned values. However, this operation is highly architecture-dependent and assumes a specific word size, so it may vary based on the system being used.
The statement is true. When converting a field in an instruction that represents a number of machine words to byte level addressing, shifting the number right two bits is equivalent to dividing the number by 4 (2 raised to the power of 2), which essentially converts the number from word-level addressing to byte-level addressing. By filling in with zeros on the left, we ensure that the value remains the same since shifting right by two bits effectively discards the two least significant bits.