Common misconception with C. A pointer does not mean a pointer to a sequence of capacitors in your RAM-memory. It really means a pointer to an abstract and temporary variable. How this abstract variable is executed on your hardware is implementation specific. Everything except input, output and explicitly defined side effects (volatile) is of no interest.
Really, you can print a c program on piece of paper and ask some slave to "execute" the program in his head given some input x, how he "implements" memset will surely be different than what a computer would, and if you only ask for the output y he will surely see that this memset doesn't affect y at all and skip doing it.
Really, you can print a c program on piece of paper and ask some slave to "execute" the program in his head given some input x, how he "implements" memset will surely be different than what a computer would, and if you only ask for the output y he will surely see that this memset doesn't affect y at all and skip doing it.