Abstract: A method used to test the correctness of image data transited between the system memory and display memory is described as follows. First, a image data A is stored in a location B of the system memory. Then, the data of image A and a location C of display memory are stored into a Bitblt temporary storage means. The Bitblt engine is used to transit the data of image A stored in the location B of system memory to the location C of display memory. Then, the data of location C, location D of display memory, and image A are input into the Bitblt temporary storage means. The Bitblt engine is used to transit the data of image A from the location C to the location D of display memory. The data of image A and location E are input into the Bitblt temporary storage means. The Bitblt engine is used to transit the data of image A from the location D into the location E of the system memory.

Abstract: A method for testing noise of a record/play-back loop in an audio system of a personal computer (PC) system is disclosed. The audio system comprises an analog-to-digital (A/D) converter, an FM synthesizer, an FM register, a mixer, an output device, an input device, and a connection element connected between the output device and the input device. The PC system has a system bus for communicating with the A/D converter and the FM synthesizer.