char[] to hex string exercise

Question

Below is my current char* to hex string function. I wrote it as an exercise in bit manipulation. It takes ~7ms on a AMD Athlon MP 2800+ to hexify a 10 million byte array. Is

Answer 1

I have found that using an index into an array, rather than a pointer, can speed things up a tick. It all depends on how your compiler chooses to optimize. The key is that the processor has instructions to do complex things like [i*2+1] in a single instruction.