Alloca implementation

Question

How does one implement alloca() using inline x86 assembler in languages like D, C, and C++? I want to create a slightly modified version of it, but first I need to know how

Answer 1

I recommend the "enter" instruction. Available on 286 and newer processors (may have been available on the 186 as well, I can't remember offhand, but those weren't widely available anyways).