NASM - The Netwide Assembler

NASM Forum => Programming with NASM => Topic started by: maplesirop on April 01, 2013, 05:34:08 PM

Title: How can I know the instruction format of a given computer system
Post by: maplesirop on April 01, 2013, 05:34:08 PM

I know how to get the number of bits of an opcode based on the number of instructions, but how do you know the size of the operand field for instance?

Title: Re: How can I know the instruction format of a given computer system
Post by: hhh3h on April 04, 2013, 04:24:37 PM

As far as I understand, that information is not something you "get" with code.  You need to know what platform you're coding for before you start coding.  For example, if you want to write a program for the family of x86 or x86-64 CPU's, you can refer to the Intel manuals for this information.  On the other hand, if you want to write a program for an ARM CPU, you would get the manual from ARM