Patent ID: 7861044

Claim:
A memory access method for accessing a memory of a computer system according to a function ID instruction, wherein the function ID instruction comprises a first function ID value and a second function ID value, the computer system comprises a south bridge and a general purpose register, the south bridge has a first index port and a second index port, a first data port and a default I/O port, and the method comprises: (a) inputting an address value corresponding to the first function ID value to the second index port under the operation of a call-back function and entering an SMM mode; (b) in the SMM mode, transferring and storing the address value to the general purpose register from the second index port, exiting from the SMM mode and returning to the operation of the call-back function; (c) inputting a default value to the default I/O port according to the function ID instruction under the operation of the call-back function and entering the SMM mode; and (d) in the SMM mode, inputting the address value corresponding to the first function ID value to the first index port, meanwhile performing a memory access corresponding to the second function ID value on the first data port according to the address value.