An Instruction Set Simulator (ISS) is a simulation model, usually coded in a high-level language, which mimics the behavior of a processor by reading instructions and maintaining internal variables which represent the processor's registers. It is generally used to improve the speed performance of simulations involving a processor core where the processor itself is not one of the elements being verified; verilog simulation with ISS by means of PLI speeds considerably. A simulation is an imitation of some real device or state of affairs. ... Model has many different meanings, depending on the context. ... Microprocessors, including an Intel 80486DX2 and an Intel 80386 A microprocessor (abbreviated as µP or uP) is a computer electronic component made from miniaturized transistors on a single semiconductor integrated circuit (IC) (aka microchip or just chip). ... The Verilog HDL is a hardware description language, used for the design of ASICs and FPGAs in order to make digital circuits. ...

An ISS is often provided with debugger GUI in order for an software engineer to debug the program prior to obtaining target hardware. It is sometimes integrated peripheral circuits such as timers, interrupts, serial port, general I/O port, etc to mimic the behavior of microcontroller. A debugger is a computer program that is used to debug (and sometimes test or optimize) other programs which might be running on the same computer (host computer) as the debugger is running, might be running on the target hardware, or might be running on the ISS. When the program... A timer is a specialized type of clock. ... In computer science, an interrupt is a signal from a device which typically results in a context switch: that is, the processor sets aside what its doing and does something else. ... A male DB-9 serial port on the rear panel of a PC. In computing, a serial port is an interface on a computer system with which information is transferred in or out one bit at a time (contrast parallel port). ... Memory-mapped I/O (MMIO) and port I/O (also called port-mapped I/O or PMIO) are two complementary methods of performing input/output between the CPU and I/O devices in a computer. ... A microcontroller is a computer-on-a-chip used to control electronic devices. ...