Can a CPU process instructions as data?

Question

While preparing for an exam, I came across this doubt. Does a CPU process instructions as data?

So there is a (for example an assembly) instruction, LDA $04. It would look like 90 04 in machine code and 10010000 00000100 in binary. So does cpu can process it as data? — InsulT, Apr 08 '13 at 17:56
Absolutely. "Code is data" is a common phrase in some parts of the software industry. — Dave Newman, Apr 08 '13 at 18:05

score 2 · Accepted Answer · edited Apr 08 '13 at 18:15

The short answer is yes. There's a Wikipedia entry on it. The gist of it is, if you have the address of the instructions you would like to read, then you can load those into data registers, test the instructions, and even write back new instructions. Many modern operating systems will probably not allow you write the instructions back however. It is a safety precaution to prevent malicious code from modifying your system, or trust applications.

score 1 · Answer 2 · answered Apr 08 '13 at 18:18

1

Depends on the computer:

In von Neumann architecture, yes.
In Harvard architecture, no.

answered Apr 08 '13 at 18:18

NPE

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Can a CPU process instructions as data?

2 Answers2