Excessive optimization (was Re: what was VMS/OpenVMS written in?)

[Ethan Dicks]

On Thu, Dec 2, 2010 at 3:47 PM,  <arcarlini at iee.org> wrote:
> He wouldn't believe that the FORTRAN compiler had helpfully turned the
> loop into a simple assignment until I showed him exactly what it had done in
> the listing file.

I've done that "slowdown" trick in embedded code and had it optimized
down to a simple assignment.  I've found that rather than tweak the
compilier, tweaking the code this much...

for (i=0; i < 100; i++) {
  a=i;
}

(i.e. - putting something active in the loop)

... was enough to leave the loop in and generate a few cycles for the
delay.  If I'm in an environment where C and assembler are mixed (not
uncommon with microcontroller programming), a #asm/NOP construct
works, too.

-ethan