6 Aug
2006
6 Aug
'06
4:18 p.m.
On Sunday 06 August 2006 06:10 pm, Ray Arachelian wrote:
Now, the 8086 itself, is also reasonably ok, but then,
you get into weird
issues where you can only use some registers for some operations, but not
others.
That's one of the things about these parts that's always bothered me.
Then, the next wrong turn was the 386 line. Once you
go into 32 bit
mode, the old 8 and 16 bit opcodes no longer make any sense and the
whole thing just gets ugly. Intel should have gone to a new set of
opcodes altogether - a clean 32 bit set of opcodes with enough registers.
Yes.
To provide an example: SPARC is a 32 bit RISC
architecture. Sun could
have really screwed things up when they went to 64 bits. Instead, they
did the right thing. They extended all of the registers to 64 bits, and
added a new 64 bit status register. So your code is backwards
compatible to 32 bit code, however, with a simple switch, it can run in
64 bits without getting all ugly, without things like segment registers
and weirdo addressing modes. It started out cleanly from the start, and
this perhaps helped them move to 64 bits more easily.
Sounds good to me, though I'm not familiar with that stuff, or a lot of what
else gets talked about in here. But learning about it all is a part of why
I'm in here anyway, so that's not much of a problem except for those times
when I just don't follow stuff...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin