Re: OT: Programming Languages

On Fri, 1 Nov 2024 16:03:00 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

On 11/1/2024 3:50 PM, Nick Hayward wrote:

What about C++?

>
C++ is an order of magnitude more complex than C.  Even a
casual C programmer can imagine what his code will look
like after compilation.  I.e., can imagine exactly what the
CPU will be doing (ignoring the fact that the compiler will
often out-think the coder in terms of time/space efficiency).

We want to time the execution of a control algorithm. One way to time
it is to run it in a loop maybe 100K times and measure that with a
stopwatch. But a very smart compiler might run it once, notice that
nothing has changed, and skip the reruns.

It's best to bang a port pin and measure it with an oscilloscope.

We've had FPGA compilers do that sort of thing, optimize out
intentional delays. One fix is to XOR signals with a level from a pin
that *we* know is always low.