Yes, you can use ESP in tight loops, done so many times in the past for software texture mapping, image processing, etc., but... debugging it is not fun. Where'

Yes, you can use ESP in tight loops, done so many times in the past for software texture mapping, image processing, etc., but... debugging it is not fun. Where's my stack frame? Wouldn't want to use it in 2015. Luckily in 2015 (=x86-64) you have 14 or 15 GP registers and 16 128-bit (or 256-bit) vector registers. While still keeping immediate values too, those don't consume a register. So much breathing space.