Similarities between hardware and software

#Similarities between hardware and software software#

#Similarities between hardware and software software#

Software invoked interrupts (triggered by the INT instruction) behave in a trap-like manner. Used to report severe errors, such as hardware errors and inconsistent Restart of the program or task that caused the exception. Location of the instruction causing the exception and does not allow a (The handler would need a pointer to the faulting instruction to figure out which instruction it was.) AbortДЄn abort is an exception that does not always report the precise The application will continue where it left off (at the faulting instruction that was accessing swapped out memory), but this time the memory access should succeed without faulting.ДЄn illegal-instruction fault handler that emulates floating-point or other missing instructions would have to manually increment the return address to get the trap-like behaviour it needs, after seeing if the faulting instruction was one it could handle. The kernel can pull that memory from disk to ram, and hand control back to the application. The application will trigger a page fault when it tries to access memory that was swapped out. A piece of an application's address space may have been swapped out to disk from ram. Instruction, rather than to the instruction following the faultingД®xample: A page fault is often recoverable. The return address (saved contents of the CS andД®IP registers) for the fault handler points to the faulting Machine state to the state prior to the beginning of execution of theДЇaulting instruction. When a fault is reported, the processor restores the Once corrected, allows the program to be restarted with no loss ofД¬ontinuity. FaultДЄ fault is an exception that can generally be corrected and that, The return address for the trap handler points to the instruction toД«e executed after the trapping instruction. Program or task to be continued without loss of program continuity. TrapДЄ trap is an exception that is reported immediately following theД®xecution of the trapping instruction.

Summary: traps increment the instruction pointer, faults do not, and aborts 'explode'. That caused the exception can be restarted without loss of program or Exception ClassificationsД®xceptions are classified as faults, traps, or aborts depending on the way they are reported and whether the instruction Page faults, and internal machine faults. The processorДetects a variety of error conditions including protection violations, ExceptionsД®xceptions occur when the processor detects an error condition whileД®xecuting an instruction, such as division by zero. Interrupts by executing the INT n instruction. Interrupts to handle events external to the processor, such as Interrupts occur at random times during the execution of a program, in response to signals from hardware. Interrupt handlers are described within the Interrupt Descriptor Table. Vectored Events ( interrupts and exceptions) cause the processor to jump into an interrupt handler after saving much of the processor's state (enough such that execution can continue from that point later).Д®xceptions and interrupts have an ID, called a vector, that determines which interrupt handler the processor jumps to.

For the (definitive and complex) x86 perspective, I recommend reading the SDM's chapter on Interrupt and Exception handling. Intel x86 defines two overlapping categories, vectored events ( interrupts vs exceptions), and exception classes ( faults vs traps vs aborts).ДЄll of the quotes in this post are from the April 2016 version of the Intel Software Developer Manual. Traps are a type of exception, and exceptions are similar to interrupts. Traps and interrupts are closely related.