Delay routines in C are fairytales. There is absolutely nothing in the C standard that makes the compiler designer have any concern for maintaining execution speed of ANY statement. The fact that to do a delay routine in C you have to code - measure -adjust says it all.

Of course, if you never upgrade your compiler you can do it, but how often has 'never' been proven false.

One occasion: a timing loop was written in C and a bug found in the compiler. When the updated compiler arrived and was used the program did not work. Of course, the updated compiler was blamed, but eventually it was found that the timing of the "precise timing loop" had changed as a result of the compiler fixes. A lot of good development time wasted on an assumption.

Erik