Abstract: A processor architecture to qualify software target-branch hints with hardware-based predictions, the processor including a branch target address cache having entries, where an entry includes a tag field to store an instruction address, a target field to store a target address, and a state field to store a state value. Upon decoding an indirect branch instruction, the processor determines whether an entry in the branch target address cache has an instruction address that matches the address of the decoded indirect branch instruction; and if there is a match, depending upon the state value stored in the entry, the processor will use the stored target address as the predicted target address for the decoded indirect branch instruction, or will use a software provided target address hint if available.

Abstract: The disclosure relates to predicting simple and polymorphic branch instructions. An embodiment of the disclosure detects that a program instruction is a branch instruction, determines whether a program counter for the branch instruction is stored in a program counter filter, and, if the program counter is stored in the program counter filter, prevents the program counter from being stored in a first level predictor.

Abstract: Techniques for interrupt processing are described. An exceptional condition is detected in one or more stages of an instruction pipeline in a processor. In response to the detected exceptional condition and prior to the processor accepting an interrupt in response to the detected exceptional condition, an instruction cache is checked for the presence of an instruction at a starting address of an interrupt handler. The instruction at the starting address of the interrupt vector table is prefetched from storage above the instruction cache when the instruction is not present in the instruction cache to load the instruction in the instruction cache, whereby the instruction is made available in the instruction cache by the time the processor accepts the interrupt in response to the detected exceptional condition.

Abstract: An instruction cache system having a virtually tagged instruction cache which, from a software program perspective, operates as if it were a physically tagged instruction cache is disclosed. The instruction cache system also includes a means for address translation which is responsive to an address translation invalidate instruction and a control logic circuit. The control logic circuit is configured to invalidate an entry in the virtually tagged instruction cache in response to the address translation invalidate instruction.

Abstract: Techniques for interrupt processing are described. An exceptional condition is detected in one or more stages of an instruction pipeline in a processor. In response to the detected exceptional condition and prior to the processor accepting an interrupt in response to the detected exceptional condition, an instruction cache is checked for the presence of an instruction at a starting address of an interrupt handler. The instruction at the starting address of the interrupt vector table is prefetched from storage above the instruction cache when the instruction is not present in the instruction cache to load the instruction in the instruction cache, whereby the instruction is made available in the instruction cache by the time the processor accepts the interrupt in response to the detected exceptional condition.

Abstract: An instruction cache system having a virtually tagged instruction cache which, from a software program perspective, operates as if it were a physically tagged instruction cache is disclosed. The instruction cache system also includes a means for address translation which is responsive to an address translation invalidate instruction and a control logic circuit. The control logic circuit is configured to invalidate an entry in the virtually tagged instruction cache in response to the address translation invalidate instruction.