On Thu, Jul 31, 2008 at 2:47 PM, David Brown <[EMAIL PROTECTED]> wrote: > On Thu, Jul 31, 2008 at 02:50:48PM -0500, Gabriel Sechan wrote: > >>> Every ARM emulator accepts 32 bit instructions. 32 bits is "only" 4 >>> billion. >>> I just need to compare the state of RAM, registers and CPU before and >>> after a >>> 32 bit instruction for a measly 4 billion of them!!! Maybe it would >>> finish >>> overnight and so I could wake up with proof in hand! >>> >>> Of course I'd have to do this for various initial states of CPU, RAM and >>> registers since hardware isn't stateless like HTML. >> >> Sure. Now lets say we have 10 registers of 32 bits. Since we don't >> know how they may effect state we have to try all combinations, that's >> a mere 2^320 states per instruction, for a mere 2^352 total tests. Let >> me know when they finish, and we can start testing ram configurations >> :) > > Why not make it even worse (and still realistic). The CPU has a > pipeline, so the instructions don't execute independently. With modern > non-strongly ordered memory, you have to check possibly large sequences > of instructions to make sure they do the same things with memory > interactions. > > I think, generally once a "solution" requires more compute steps than > the size/age of the known universe it is safe to consider it > "impractical". > > David
But that is only 6000 years! http://www.albatrus.org/english/theology/creation/biblical_age_earth.htm BobLQ "Here we go again." -- KPLUG-List@kernel-panic.org http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
