=20

quoted

Which is a problem because the compiler could schedule
it be written back to real memory between the instructions.

=20
It can? There is no memory here, just registers. Even if it
is written to memory, how would that affect the register?

Although the function argument is passed in a register, the
compiler could generate a store-load sequence before and
after each __asm__() line.

Assuming you are right, would rewriting it to
  __asm__("rlwimi %0,%0,16,0x00ff0000\n\t"
	    "rlwinm %0,%0,24,0x0000ffff"
	    : "+r"(value));
help?

Except that now you've stopped the compiler scheduling
another instruction between the two - probably forcing a
execution stall.

	David