4 Jun
2013
4 Jun
'13
8:06 a.m.
On Mon, Jun 03, 2013 at 07:39:44PM -0000, Cory Smelosky wrote:
[...]
That's what bothers me about the x86
architecture...it gets such a kludgy
mess due to tacking it all on. Intel EM64T: it's amd64 so 64-bit with 32-bit
x86 which is tacked on to a 16-bit architecture which is tacked on to an
8-bit architecture and so on...
Instruction decoding is such a tiny part of the CPU die these days that it
hardly matters that the chips support all those weird legacy modes. Intel could
throw in support for decoding ARM, VAX, PDP-11 and Jacquard loom instructions
and still have a few acres of space left over.
While real mode etc are indeed utterly hateful, doing the magic to switch the
CPU into long mode makes it all go away and leaves an architecture with a
decent number of general-purpose registers and a perfectly acceptable
instruction set.