Microprocessor with circuits, systems, and methods for selectively bypassing external interrupts past the monitor program during virtual program operation

摘要

A microprocessor (26) may multi-task a plurality of programs, and those programs include a virtual program (38 or 40) operable in a virtual mode and a monitor program (34) operable using protected mode semantics. The microprocessor includes input circuitry (INTR) for receiving an external interrupt request signal corresponding to an external interrupt directed to the virtual program, and additional input circuitry (INT#0-7) for receiving an external interrupt number corresponding to the external interrupt directed to the virtual program. The microprocessor further includes an interrupt handling circuit (30) comprising circuitry for identifying an interrupt vector and presenting an interrupt corresponding to the external interrupt request number. Lastly, the microprocessor includes control circuitry (28) coupled to the interrupt handling circuit. The control circuitry includes circuitry for detecting receipt (48) of the external interrupt request signal, and circuitry (46), responsive to receipt of the external interrupt request signal and the external interrupt number, for providing a select signal to the interrupt handling circuit. The interrupt handling circuit identifies the interrupt vector using protected mode semantics (66) and presents an interrupt to the monitor program in response to the select signal comprising a first state, and the interrupt handling circuit identifies the interrupt vector using a second set of semantics (64) differing from the protected mode semantics and presents an interrupt to the virtual program in response to the select signal comprising a second state.