| 摘要 |
A computer system and method for performing wavetable music synthesis employing a high priority I/O bus request mechanism to improve the audio fidelity of the system. The system comprises a system memory which stores wavetable data, an I/O bus coupled to the system memory, an I/O bus arbiter coupled to the I/O bus which accommodates normal priority I/O bus requests and high priority I/O bus requests, and a system audio device. The system audio device comprises an I/O bus interface coupled to the I/O bus, a synthesizer coupled to the I/O bus interface, a plurality of buffers coupled to the I/O bus interface and to the synthesizer and a buffer manager coupled to the I/O bus interface, the synthesizer, and the plurality of buffers. The synthesizer generates a request for wavetable data samples. The buffer manager determines if the samples are in the buffers. If the samples are in the buffers but one of the buffers has become a predetermined amount empty, the buffer manager generates a normal fill request to the I/O bus interface. The I/O bus interface generates a normal priority I/O bus request to the I/O bus arbiter in response to the normal fill request. If the samples are not in the buffers, the buffer manager generates a high priority fill request to the I/O bus interface. The I/O bus interface generates a high priority I/O bus request to the I/O bus arbiter in response to the high priority fill request. When the I/O bus arbiter grants bus mastership to the I/O bus interface, the buffer manager fetches the samples from the system memory. The synthesizer generates sounds in response to the wavetable data samples.
|
