Abstract: Methods and apparatus to perform event handling operations are described. In one embodiment, after an event (such as an architectural event occurs), the corresponding occurrence response (e.g., a yield event) may cause generation of an interrupt. Other embodiments are also described.

Abstract: A method and apparatus for performing a system call in a system having a user privilege level and a kernel privilege level, wherein the kernel privilege level is higher than the user privilege level is disclosed. A sequence of instructions is executed at the user privilege level including a first instruction that requires a resource provided at the kernel privilege level. Control is transferred to a first procedure executing at the user privilege level by performing a near call and saving only a pointer to the first instruction. The first procedure includes a calling instruction that does not save an architectural state prior to transferring control. Control is transferred from the first procedure to a second procedure executing at the kernel privilege level. The second procedure determines the resource required by the first instruction. Control is transferred from the second procedure to a third procedure that is determined by the second procedure.

Abstract: A method and apparatus for handling events, such as those which occur in a processor. An event vector is formed by combining event type information indicating a type of event in the processor and mode information indicating an operating mode of the processor. A microcode event handler vector is generated therefrom, for example, by referencing a lookup table. The microcode event handler vector is then used for invoking a microcode event handler to handle occurrence of these events in the processor. By the formation of an event vector, and the microcode event handler vector, execution performance is increased due to avoiding conditional branching within the processor, such as modem high performance architectures, including those which execute instructions in and out-of-order.