InlineAssembly in C [Old Content]

Kyle Brady — Tue, 26 May 2009 16:40:01 +0000

The final homework project package for my CS47 class has been posted, albeit weeks after being due - I had some local SVN Client problems.

Essentially, we had to convert some C functions into their inline assembly counterparts. See the PDF file for details.

All code is available via SVN, and a web-browsing utility.

Note: I am not advocating using this code in place of doing your own homework, or in any situation other than pure interest. However, in the event that you do, I am not responsible for any resultant issues (legal, moral, or ethical) that may arise. Finally, I am not presenting these as perfect cases, the best way to approach the problems, nor the fastest. They are, simply, viable solutions.

asmParser – A Lesson In Research [Old Content]

Kyle Brady — Fri, 08 May 2009 01:42:00 +0000

In my CS47 class, we've just started working on using Inline Assembly (assembly code processing built into the gcc compiler), and I thought the way you do it is pretty ugly. The assembly, which is put inside a C file, looks like this:

asm("command1\t\n","command2\t\n","command3\t\n");

Keep in mind that's wrapped inside a C file. Assembly. In a C file.

Naturally, I thought there was probably a more clever way to do this - I knew that asm() wasn't a true function, that it was a compiler instruction, but I assumed that it would pretend to be like a function and accept a variable as an argument.

Nope.

But I didn't discover that I was wrong until I got weird errors while compiling:

gcc -S -masm=intel ./asmParser.c

-> error: argument of 'asm' is not a constant string

This is when I jumped onto #c on irc.freenode.net, and was essentially laughed at. I guess that's what I get for trying to be clever... too clever.

You can find the everything-works-but-the-asm()-part code here with the exampleCommands file, or download everything as a zip file.

Next time I'm going to do a little more research!

Kyle Brady: Blog » Inline Assembly

InlineAssembly in C [Old Content]

asmParser – A Lesson In Research [Old Content]