AMD AMD-K6-2/500AFX Data Sheet - Page 128

AMD-K6®-2 Processor Data Sheet Preliminary Information 21850J/0-February 2000 4.30 Summary Sampled INTR (Maskable Interrupt) Input INTR is the system's maskable interrupt input to the processor. When the processor samples and recognizes INTR asserted, the processor executes a pair of interrupt acknowledge bus cycles and then jumps to the interrupt service routine specified by the interrupt number that was returned during the interrupt acknowledge sequence. The processor only recognizes INTR if the interrupt flag (IF) in the EFLAGS register equals 1. The processor samples INTR as a level-sensitive input on every clock edge, but the interrupt request is not recognized until the next instruction boundary. The system logic can drive INTR either synchronously or asynchronously. If it is asserted asynchronously, it must be asserted for a minimum pulse width of two clocks. In order to be recognized, INTR must remain asserted until an interrupt acknowledge sequence is complete. 4.31 Summary Sampled INV (Invalidation Request) Input During an inquire cycle, the state of INV determines whether an addressed cache line that is found in the processor's instruction or data cache transitions to the invalid state or the shared state. If INV is sampled asserted during an inquire cycle, the processor transitions the cache line (if found) to the invalid state, regardless of its previous state. If INV is sampled negated during an inquire cycle, the processor transitions the cache line (if found) to the shared state. In either case, if the cache line is found in the modified state, the processor writes it back to memory before changing its state. INV is sampled on the clock edge on which EADS# is sampled asserted. 108 Signal Descriptions Chapter 4