process - 进程的程序计数器

Question

我认为程序计数器是硬件的一部分。读完以下内容后我很困惑。有人可以澄清其中的区别吗？

A single-threaded process has one program counter specifying the next instruction to execute. (Threads are covered in Chapter 4.) The execution of such a process must be sequential. The CPU executes one instruction of the process after another, until the process completes. Further, at any time, one instruction at most is executed on behalf of the process. Thus, although two processes may be associated with the same program, they are nevertheless considered two separate execution sequences. A multithreaded process has multiple program counters, each pointing to the next instruction to execute for a given thread.

Answer 1

每个CPU都有一个硬件程序计数器。每个线程都有一个程序计数器VALUE，仅在线程执行时加载到硬件程序计数中。

如果在多处理系统上执行，一个进程可能有多个硬件程序计数器。每个线程可以在单独的处理器上运行，并在该处理器上有一个程序计数器。