Joe Buck wrote:
On Thu, May 04, 2006 at 04:31:15PM +0300, Nikolaos Kavvadias wrote:
My question here is: culdn't "-Os" optimization option force .align 0
alignment? Is there any way to use the minimal data memory
requirements for global symbols possible?
While it could, I hope that it does not go so far as to make the
reads unaligned (on processors that allow this). -Os currently
optimizes well for speed as well as for space, and there's a substantial
performance penalty for unaligned reads and writes in many cases.
IIRC, On mips they are trapped and emulated in the Linux/(your OS here)
kernel. That means that literally hundreds of instructions are executed
for each unaligned access.
On systems where they are not emulated, you would get a hard failure.
David Daney.
