Re: __asm__ C code in mips-Linux

["Kevin D. Kissell" <kevink@mips.com>]

> extern __inline__ void atomic_add(int i, atomic_t * v)
> {
> unsigned long temp;
> 
> __asm__ __volatile__(
> "1:   ll      %0, %1      # atomic_add\n"
> "     addu    %0, %2                  \n"
> "     sc      %0, %1                  \n"
> "     beqz    %0, 1b                  \n"
> : "=&r" (temp), "=m" (v->counter)
> : "Ir" (i), "m" (v->counter));
> }
> 
> 
> Beginner questions on the above code...

See http://gcc.gnu.org/onlinedocs/gcc-2.95.3/gcc_4.html#SEC93
or any of a number of other on-line copies of the gcc documentation.
Gcc has a very powerful and cool means of binding C variables to
assembly-language operands.  The syntax can be painful, but you
can do amazing things with it - in this case, an in-line atomic add
for C.