🔒 Locked

inline assembly?

Started by Venerable Vampire Jun 8, 2004 at 5:46 PM 1 replies 450+ views

Original Post

Jun 8, 2004 at 5:46 PM

I''m terribly confused. I''ve heard about something called "inline assembly". I have no idea what this is. How does it relate to normal assembly? What exactly can you do with it? What is up with the "__asm" keyword in my c compiler? Also, I thought assembly was rather machine specific, while c syntax is not (not talking about API, just the syntax). Can someone explain assembly and c for me or point to a tutorial? -------------------------------------------------------- Life would be so much easier if we could just get the source code.

dcosborn

Jun 8, 2004 at 6:06 PM

Inline assembly is a compiler-specific extension that allows you to insert assembly code in the middle of regular C code. Yes, its machine specific, so you need to know your target platform beforehand. The __asm keyword tells the compiler that all the code within its scope is assembly. So you can usually write either:

__asm mov eax, 0
__asm cmp ebx, eax

or

__asm
{
mov eax, 0
cmp ebx, eax
}

Note that the prefixed underscores denote compiler-specific keywords. How the assembly code integrates with the C code depends on your compiler. Also note that GCC handles x86 assembly in AT&T syntax, which is unusual and you can google for it.

[edited by - dcosborn on June 8, 2004 7:12:44 PM]

Charles B

Jun 9, 2004 at 6:58 AM

Note : inline asm is much more interesting (but also more complex to handle) under gcc.

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.