Patent ID: 8176263
Filing Date: 2012-05-08
Classification: G06F

Abstract:
1. A memory management apparatus comprising: a data memory; a link list memory; a plurality of access units that write and read data from the data memory, the plurality of the access units are divided into plural access groups, each of the plurality of the access units belonging to at least one of the plural access groups, a control unit configured to manage a use area of the data memory and a vacant area of the data memory by using the link list memory when a data-writing operation to the data memory or a data-reading operation from the data memory is requested by one of the plurality of access units; a queue top register in each of the plurality of the access units capable of storing a top address of the use area of the data memory that is used by respective access units; a queue end register in each of the plurality of the access units capable of storing an end address of the use area of the data memory that is used by respective access units; a queue counter in each of the plurality of the access units capable of counting an area size used by respective access units, and each of the plural access groups has a queue counter; an idle top register capable of storing a top idle address of the vacant area; an idle end register capable of storing an end idle address of the vacant area of the data memory; an idle counter capable of counting a vacant area size; and a virtual idle counter capable of storing a difference value between an idle counter value and a total of differences between counter values and minimum queue counter values of respective queue counters if a counter value is smaller than a minimum queue counter value in respective queue counters, wherein the respective queue counters have a maximum counter value and a minimum counter value that corresponds to a minimum queue reservation number, wherein the control unit sets only a maximum value for the queue counter of each of the plural access groups, the control unit performs a same determination process for the maximum value of the queue counter as the maximum value of the queue counter of each of the plurality of the access units, the control unit uses the queue counter of each of the access groups in a queue count operation in a same manner as the queue counter of each of the plurality of the access units, the control unit performs as a write control unit, when a write request from one of the plurality of the access units exits, the write control unit performs following processes, the following processes include: