[okl4-developer] KernelInterface syscall on ia32

[Harry Vennik]

Hi,

I wonder how the KernelInterface syscall actually works for ia32.

In arch/ia32/libs/l4/include/syscall.h the KernelInterface syscall  
stub is implemented as:

INLINE void *
L4_KernelInterface(L4_Word_t *ApiVersion,
                    L4_Word_t *ApiFlags, L4_Word_t *KernelId)
{
     void *base_address;

     __asm__ __volatile__("/* L4_KernelInterface()  
*/                    \n"
                          "   lock; nop                                
\n"
                          :    /* outputs */
                          "=a"(base_address),
                          "=c"(*ApiVersion), "=d"(*ApiFlags),  
"=S"(*KernelId)

                          /*
                           * no inputs
                           */
                          /*
                           * no clobbers
                           */
         );

     return base_address;
}

This looks like a 'nop' instruction is doing the work, which can't be  
true because a 'nop' does nothing...
So how do those output registers get their values?

Btw: is there an ABI doc anywhere for OKL4 on ia32? The progmanual  
only includes the ABI for ARM...

Regards,

Harry
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