发明名称 |
Case block table for predicting the outcome of blocks of conditional branches having a common operand |
摘要 |
A method and apparatus is disclosed for folding the execution of a multi-way branch or switch based upon an operand (e.g.,the block of instructions normally associated with a case statement) into a single instruction. This insulates branch prediction mechanisms from making incorrect predictions that are normally associated with a multi-way branch. A table saves the past history of multi-way branch execution. This table contains three fields: the starting address of a multi-way branch; a value of the operand used to execute that multi-way branch in the past; and the larger target address generated by that multi-way branch in the past when that particular operand value was used. In accordance with one embodiment of this invention, other branch prediction mechanisms (such as a Branch History Table or Decode History Table) are disabled from redirecting instruction fetching during execution of a multi-way branch in an instruction stream.
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申请公布号 |
US5333283(A) |
申请公布日期 |
1994.07.26 |
申请号 |
US19910784335 |
申请日期 |
1991.10.29 |
申请人 |
INTERNATIONAL BUSINESS MACHINES CORPORATION |
发明人 |
EMMA, PHILIP G.;KAELI, DAVID R. |
分类号 |
G06F9/32;G06F9/38;(IPC1-7):G06F9/38;G06F9/345 |
主分类号 |
G06F9/32 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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