VLA in Assembler

[Foo via Digitalmars-d-learn]

On Wednesday, 17 December 2014 at 10:59:09 UTC, bearophile wrote:
> Foo:
>
>> Hi,
>> Could someone explain me, if and how it is possible to 
>> allocate a variable length array with inline assembly?
>> Somewhat like
>> ----
>> int[] arr;
>> int n = 42;
>> asm {
>>    // allocate n stack space for arr
>> }
>> ----
>> I know it is dangerous and all that, but I just want it know. 
>> ;)
>
> Doing it with alloca is simpler:
>
>
> void main() @nogc {
>     import core.stdc.stdlib: alloca, exit;
>
>     alias T = int;
>     enum n = 42;
>
>     auto ptr = cast(T*)alloca(T.sizeof * n);
>     if (ptr == null)
>         exit(1); // Or throw a memory error.
>     auto arr = ptr[0 .. n];
> }
>
>
> Bye,
> bearophile
Yes I know, but I really want it in inline assembly. It's for 
learning purpose. :)