The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 19, 1999
Filed:
Mar. 15, 1996
Mohammed Sriti, Milpitas, CA (US);
Rendition, Inc., Mountain View, CA (US);
Abstract
An apparatus and method for performing byte swapping using a direct memory access (DMA) controller is provided. In a computer system, a DMA controller for a peripheral component is coupled to system memory via a bus. The DMA controller receives a command pointer to initiate a memory access operation. The command pointer specifies the location of the first DMA command in a command list to be executed by the DMA controller. Each DMA command includes an address word giving the starting address and length word indicating the number of data words to be accessed in memory. Because the data stored in memory is double-word aligned, the two least significant bits of the length word are not needed to perform the memory access and are instead used to indicate any byte swapping that is to be performed on the data during the memory access. During a memory access, the DMA controller swaps the bytes in each double-word of data as specified by the two least significant bits of the length word.