Please correct this code

From: Sri Ram Vemulpali
Date: Mon Jan 31 2011 - 11:37:59 EST


I have following snippet of code.

Code A

__asm__ __volatile__(
" lock ;\n"
" addl %1,%0 ;\n"
: "=m" (my_var)
: "ir" (my_int), "m" (my_var)
: /* no clobber-list */

Code B

__asm__ __volatile__( "decl %0; sete %1"
: "=m" (my_var), "=q" (cond)
: "m" (my_var)
: "memory"

In Code A memory contents are getting updated. And in Code B memory
contents and 'cond' var are getting updated.
In Code B in cobbler column 'memory' is used to indicate that this
code modifies memory contents. But where as in Code A it was not

Is is not that Code A is wrong, for not mentioning cobbler list
'memory' to indicate memory contents are getting updated.
Please rectify me, if I am wrong.

Also, what does '+m' constraint mean, if I use in inline assembly.
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