considering a 32-bit computer and a complete instruction like

mov eax,3


how many bits the whole of that instruction take?
Posted on 2011-01-13 04:35:42 by ashken
'A 32-bit computer' is too vague.
The instruction size depends on the instructionset, so you need to know exactly which instructionset we're talking about.
In the case of x86, it's one big mess, you not only need to specify that it's x86, but also which generation of x86 it is, and in which mode it's running (16-bit, 32-bit or 64-bit)... and even then, certain instructions can be encoded in more than one way.

All in all, sounds a bit like a homework question to me.
I don't think this question requires an exact answer anyway. What you need to do is to grab the instruction set reference for the particular CPU, and figure out how it encodes its instructions. Then you can work out the size for yourself. Knowing how to work it out is important, not how many bits this instruction is.
Posted on 2011-01-13 04:48:45 by Scali
Ok i was referring to x86 architecture and its not homework, i was just curious after seeing a video about MIPS instruction set architecture.I don't know what manuals you are referring to but the Intel manuals are not so much detailed
Posted on 2011-01-13 05:06:27 by ashken
The Intel manuals are perfectly detailed.
This has everything you need to know:
http://www.intel.com/assets/pdf/manual/253666.pdf
Posted on 2011-01-13 05:34:38 by Scali