发明授权
US07552314B2 Fetching all or portion of instructions in memory line up to branch instruction based on branch prediction and size indicator stored in branch target buffer indexed by fetch address 有权
根据存储在由抓取地址索引的分支目标缓冲区中的分支预测和大小指示符,将内存行中的所有或部分指令取出到分支指令

  • 专利标题: Fetching all or portion of instructions in memory line up to branch instruction based on branch prediction and size indicator stored in branch target buffer indexed by fetch address
  • 专利标题(中): 根据存储在由抓取地址索引的分支目标缓冲区中的分支预测和大小指示符,将内存行中的所有或部分指令取出到分支指令
  • 申请号: US11252029
    申请日: 2005-10-17
  • 公开(公告)号: US07552314B2
    公开(公告)日: 2009-06-23
  • 发明人: Anatoly GelmanRussell Schnapp
  • 申请人: Anatoly GelmanRussell Schnapp
  • 申请人地址: US TX Carrollton
  • 专利权人: STMicroelectronics, Inc.
  • 当前专利权人: STMicroelectronics, Inc.
  • 当前专利权人地址: US TX Carrollton
  • 代理商 Lisa K. Jorgenson; William A. Munck
  • 主分类号: G06F9/38
  • IPC分类号: G06F9/38
Fetching all or portion of instructions in memory line up to branch instruction based on branch prediction and size indicator stored in branch target buffer indexed by fetch address
摘要:
The invention provides a method and apparatus for branch prediction in a processor. A fetch-block branch target buffer is used in an early stage of pipeline processing before the instruction is decoded, which stores information about a control transfer instruction for a “block” of instruction memory. The block of instruction memory is represented by a block entry in the fetch-block branch target buffer. The block entry represents one recorded control-transfer instruction (such as a branch instruction) and a set of sequentially preceding instructions, up to a fixed maximum length N. Indexing into the fetch-block branch target buffer yields an answer whether the block entry represents memory that contains a previously executed a control-transfer instruction, a length value representing the amount of memory that contains the instructions represented by the block, and an indicator for the type of control-transfer instruction that terminates the block, its target and outcome. Both the decode and execution pipelines include correction capabilities for modifying the block branch target buffer dependent on the results of the instruction decode and execution and can include a mechanism to correct malformed instructions.
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