That way lies madness
Posted Sep 2, 2011 5:35 UTC (Fri) by eru
In reply to: The x32 system call ABI
Parent article: The x32 system call ABI
the idea behind the x32 architecture is to be able to take advantage of these extra registers (which almost always result in improved performance) without having to pay the overhead of larger pointers to memory.
I can see the reasoning, but still I feel the ideal is very bad. It reminds me too much of the "memory models" of MS-DOS, 16-bit Xenix and 16-bit OS/2, and the problems associated to having then separate library versions of each, and slightly different requirements and capacities of programs depending on how they were compiled. Been there, and did not like it. Please don't bring this mess to Linux!
Having more modes just means more available ways for the programmer to screw things up, and more possibilities for low-level bugs and security holes in the kernel and C library. The now-existing 32-bit mode in x86_64 is justifiable for supporting legacy binaries, but other memory models will just complicate things with very little gain.
to post comments)