The smallest memory units addressible and movable

These are two questions that were received under my previous question:

(1) what is the minimum amount of data (N bits) that can be moved from memory to register using only one machine instruction?

(2) When this machine instruction is used, what is the smallest address increment that lets you read the next N bits? (not overlapping with the first read)

1. I was wondering if in (1) the minimum amount of data that can be moved from memory to register using only one machine instruction is called a word, and in (2), the smallest address increment that lets you read the next N bits? (not overlapping with the first read) is called a byte?

2. In (1), is "the minimum amount of data that can be moved from memory to register using 开发者_高级运维only one machine instruction" same as

   • the minimum amount of data that can be moved to memory from register using only one machine instruction,
   • the minimum amount of data that one machine instruction can operate on, and
   • the content of a register?

3. If I am not wrong, the minimum memory units in (1) and in (2) are generally not the same. But I wonder why, i.e., how the smallest addressable memory is not

   • the smallest memory to be moved between memory and register, and
   • the smallest memory to be operated on

   by machine instructions? Can there be some assembly code to explain?

I am mainly talking about regular computer architectures, such as X86, X86-64, ....

Thanks and regards!

(1) It is called a WORD, you are correct. Word size varies depending on the CPU architecture, for most modern computers a word can either be 32 bits (4 bytes) or 64 bits (8 bytes).

(2) Most modern computers and BYTE-addressible