OSDev.org

Posted: **Thu Jan 10, 2008 6:26 am**

Is there anything that changes in gcc inline asm when you use Intel syntax.

Posted: **Thu Jan 10, 2008 6:41 am**

Google is your best friend here and otherwise search this forum as the subject has only been addressed a few million times before.

gcc -v --help reveals a -masm option
google gcc masm reveals gcc -masm=intel

took about a minute

Posted: **Thu Jan 10, 2008 6:55 am**

Unfortunately, unless I misread the GCC info page, -masm=intel affects the output of GCC, i.e. what you get when you do gcc -S...

Posted: **Thu Jan 10, 2008 5:04 pm**

I decided against intel syntax, here is my outb function

Code: Select all

void outb(uchar_t in, uint16_t outp)
{
	asm("outb %%al,%%dx"
	    : /*none to pass*/
	    :"a" (in),"d" (outp));
};

are there any errors?

Posted: **Thu Jan 10, 2008 9:24 pm**

Looks fine, except for the semicolon at the end.

Posted: **Fri Jan 11, 2008 6:15 am**

crazygray1 wrote:Is there anything that changes in gcc inline asm when you use Intel syntax.

See here or here. Basically, use ".intel_syntax noprefix" in your assembly. Cannot find whether there's an easier way.

JAL

Posted: **Fri Jan 11, 2008 6:33 am**

ucosty wrote:Looks fine, except for the semicolon at the end.

What's wrong with the semicolon? It doesn't need to be there but it doesn't cause any problems.

Posted: **Fri Jan 11, 2008 6:56 am**

It's just weird that you would put one there where none is needed. Thats all.

Posted: **Fri Jan 11, 2008 7:20 am**

The semicolon at the end of that function is Just Wrong (tm).

Posted: **Fri Jan 11, 2008 9:51 am**

crazygray1 wrote:
ucosty wrote:Looks fine, except for the semicolon at the end.
What's wrong with the semicolon? It doesn't need to be there but it doesn't cause any problems.

I think they blew up an satellite once because of a semicolon (or other character) so i would be hesitant with you remark.

@solar
Oops, my bad. I should verify before i post

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