Assembly

Assembly RSS

How to extract the opcode and the data form the instruction

•

Join Date: Oct 2006

Posts: 3

Reputation: sciconf is an unknown quantity at this point

Solved Threads: 0

sciconf

Offline

Newbie Poster

How to extract the opcode and the data form the instruction

Oct 2nd, 2006

How to extract the opcode and the data form the instruction? "instruction" is inst below in decimal. For some values of "??", I should be able to extract the opCode and data???

opCode = inst >>??;
data = inst & ??;

It is done on a x86 processor using C.
It is 16 bit in total.

Starting from 0 from the right to left.
11th to 15th bit is OpCode.

0 to 9th bit is Data.

Is there a shortcut using hexadecimal notation?

Last edited by sciconf; Oct 2nd, 2006 at 11:39 pm.

•

Join Date: Dec 2005

Posts: 5,850

Reputation: Salem has a reputation beyond repute

Solved Threads: 749

Salem

Offline

Void main'ers are DOOMed

Re: How to extract the opcode and the data form the instruction

Oct 10th, 2006

Something like

 Help with Code Tags 
 Assembly Syntax (Toggle Plain Text) 
( opc >> 11 ) & 0x3f; // 6 bits
opc & 0x3ff;  // 10 bits
( opc >> 11 ) & 0x3f; // 6 bits
opc & 0x3ff;  // 10 bits