rwessel (rwessel.delete@this.yahoo.com) on September 25, 2021 3:44 pm wrote:

> You can't really, without horrendous impact, divide stack from data on x86. Pointers from both are constantly
> intermixed. You could move some stack data (register save areas, return addresses, etc.) to a separate parallel
> stack (like IPF did, and to an extent SPARC), and that could have significant benefits (if you can't overrun
> an allocated item on the stack and hit a return address, you can't modify return addresses that way), but that
> requires substantial code overhead to implement (which isn't helped by x86 segmentation), or substantial hardware
> support (and the RSE on IPF had bugs for mostly the entire existence of the architecture).
>
> As for separating code from data - the NX and W bits in the page tables do that pretty simply.


But did i386 designers get rid of that kind of problems? You could use 32 bit address pointers to stack and effective address is calculated from stack start address. So operation can be made totally transparent to code and maintain benefits of dividing stack from data?