Sujet : Re: Making Lemonade (Floating-point format changes)
De : mitchalsup (at) *nospam* aol.com (MitchAlsup1)
Groupes : comp.archDate : 13. May 2024, 22:16:48
Autres entêtes
Organisation : Rocksolid Light
Message-ID : <9c79fb24a0cf92c5fac633a409712691@www.novabbs.org>
References : 1 2 3 4 5
User-Agent : Rocksolid Light
BGB wrote:
>
Emulation via traps is very slow, but typical for many ISA's is to just quietly turn the soft-float operations into runtime calls.
I recall that MIPS could emulate a TLB table walk in something like
19 cycles. That is:: a few cycles to get there, a hash table access,
a check, a TLB install, and a few cycles to get back.
On an x86 this would be at least 200 cycles just getting there and back.
So, to revisit your statement::
Emulation is slow when trap overhead is large and not-slow when trap overhead
is small.