System and method for directly executing user dma instruction from user

Abstract

The present invention relates to an intelligent direct memory access (DMA) controller which interprets user commands from a host system, establishes work buffers for each user process, and retrieves blocks of data from the work buffers at the user's is request, rather than at the request of the kernel software. This is accomplished by establishing work buffers for each user process which are locked into physical memory. The controlling user process will then fill one work buffer, acquire the device semaphore, start physical DMA on the locked buffer, and then start filling another buffer. Memory integrity is maintained by allowing the user to access the work buffers for DMA without knowing their physical location in memory, via work buffer pointers from work buffer pointer registers which correspond to each work buffer for each user process. These work buffer pointer registers are privileged and are updated by the host processor for each new controlling user process.