Raid XOR operations to synchronous DRAM using a read buffer and pipelining of synchronous DRAM burst read data

A method of performing an external read-modify-write cycle for a synchronous DRAM (dynamic random access memory), comprising the steps of:

• pipelining data from a synchronous dynamic random access memory (SDRAM) in a read buffer in response to a plurality of consecutive SDRAM burst read requests;
• storing write data in a write buffer;
• XORing the write data with the data from the read buffer;
• and
• writing the resulting data from XORing the write data with the data from the read buffer to the synchronous dynamic random access memory.

A bus/memory interface device, comprising:

• a synchronous dynamic random access memory controller to control a synchronous dynamic random access memory;
• and
• a memory interface controller coupled to the synchronous dynamic random access memory controller, the memory interface controller comprising:
• a read buffer to pipeline data from the synchronous dynamic random access memory (SDRAM) in response to a plurality of consecutive SDRAM burst read requests;
• a write buffer to store write data;
• an exclusive or (XOR) engine to XOR the write data with data from the read buffer;
• and
• a write interface to write the resulting data from XORing the write data and the data from the read buffer to the synchronous dynamic random access memory.

A memory interface controller, comprising:

• a means for pipelining data from a synchronous dynamic random access memory (SDRAM) in response to a plurality of consecutive SDRAM burst read requests;
• a means to store write data;
• a means to XOR the write data with the data from the synchronous dynamic random access memory;
• and
• a means to write resulting data from XORing the write data and the data from the synchronous dynamic random access memory to the synchronous dynamic random access memory.