inline assembler question

inline assembler question

[gumbold]

Hi

please tell me what it means:
#define MBARRIER() __asm__ __volatile__ ("lock; addl $0,0(%%esp)" ::: 
"memory")
#define UNLOCK_MBARRIER() __asm__ __volatile__ ("" ::: "memory")

Re: inline assembler question

[Ian Lance Taylor]

gumbold <gumbold@bonbon.net> writes:

> please tell me what it means:
> #define MBARRIER() __asm__ __volatile__ ("lock; addl $0,0(%%esp)" :::
> "memory")
> #define UNLOCK_MBARRIER() __asm__ __volatile__ ("" ::: "memory")

This is where the asm statement is documented:
    http://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/Extended-Asm.html

If you have a more specific question, ask it.

Ian

Re: inline assembler question

[Alexandre Oliva]

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On Apr 10, 2001, Michael Sänger <michael@vulpine.de> wrote:

> int function(int arg);
> {
> __asm__(" movl arg,%eax ");
> }

> doesn't work because the arg symbol isn't parsed as variable to the asm
> ...

You should read about extended asms in the GCC manual.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me

inline assembler question

[Michael Sänger]

hi there!

courrently I'm workin with gcc using inlineasm instructions for SSE and
MMX.
But there are some things i'd like to know (since i'm new to gcc i
apologize herby for newbee-questions :)

first of all, where is the arg stored?

example:
int function(int arg);
{
__asm__(" movl arg,%eax ");
}

doesn't work because the arg symbol isn't parsed as variable to the asm
...


how to tell in sse the operand-size assumption like the 'quadword ptr'
or 'xmmword ptr' in intel syntax?

example:(in itel-syntax)

float function(float *arg)
{
 __asm mov eax, dword ptr arg
 __asm movups xmm1, xmmword ptr [eax]
}

how wold this function look in gcc?


are operand and operator in the same or oppostie order than in intel
syntax?

how does the asm behave when you have mnemonics with 3 args ?
(like 'shufps' for example...)

Regards,
michael saenger

P.S. I'd be thankful for any help, or even a link to a website(but it
must be a SSE/MMX specific one :)