3 ms·
I wonder about robustness. Can the microcode physically destroy the CPU? Consider driving a bus line both high and low simultaneously from two sources. That put
by jws 9y ago
I wonder about robustness. Can the microcode physically destroy the CPU? Consider driving a bus line both high and low simultaneously from two sources. That puts transistors which ordinarily spurt out a little current to overcome capacitance into a continuous maximum current situation. Compared to maximum toggle rate in normal operation, (50% duty cycle for a transistor, exponentially decaying current when on), I’ll estimate this will easily average four times the current.
The development cycle could be littered with dead processors, but worse for Intel, if a widely used microcode has a very infrequent chip stressing flaw it will manifest as “Intel chips aren’t reliable.”
- sannee 9y agoI don't think that tri-state logic is used in ICs anymore (?). EDIT: http://vswww.kaist.ac.kr/ENGLISH/old_lecture/ee878-2002/lecture/SoC_22-OCNetwork-1113.pdf http://vswww.kaist.ac.kr/ENGLISH/old_lecture/ee878-2002/lect... It probably does not imply that the chip is indestructible through microcode though.
- DavidBuchanan 9y agoHow do busses work without tri-state logic?
- vanjoe 9y agoArbitration and multiplexing
- marcosdumay 9y agoThat paper is about a different concept only loosely related to what DavidBuchanan seems to be talking about. Selecting a register through a tri-state based bus demands a circuit with a O(1) critical path. Selecting a register through a logical selector demands a circuit with O(log n) critical path, and a large constant factor.