发明名称 |
Apparatus and method for predicting an end of loop for string instructions |
摘要 |
A superscalar microprocessor implements a microcode instruction unit that predicts the end of microcode loops. The microcode instruction unit detects a microcode loop and begins counting the number of iterations of the loop. The microcode sequence that implements the loop includes a microcode instruction that uses the string count as an operand and/or a result. The microcode instruction unit captures the string count when it is available on either an operand or address bus. The string count is compared to the number of iterations of the string loop to determine when to terminate the microcode loop. If the string count is not captured prior to the microcode instruction unit dispatching more microcode instructions than necessary, the microcode instruction unit notifies other components via a cancel bus. In this manner, the end of a loop is detected prior to the functional unit detecting a mispredicted branch instruction within the microcode loop.
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申请公布号 |
US5898865(A) |
申请公布日期 |
1999.04.27 |
申请号 |
US19970874025 |
申请日期 |
1997.06.12 |
申请人 |
ADVANCED MICRO DEVICES, INC. |
发明人 |
MAHALINGAIAH, RUPAKA |
分类号 |
G06F9/318;G06F9/32;G06F9/38;(IPC1-7):G06F9/38 |
主分类号 |
G06F9/318 |
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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