Code breakpoint decoder

专利名称：Code breakpoint decoder发明人：Mario D. Nemirovsky,Robert James

Divivier,Robert Walter Williams

申请号：US08/451198申请日：19950526公开号：US05717909A公开日：19980210

摘要：A computer with a pipelined processor and code breakpoints for performingsoftware debug operations includes prefetch and decode stages, debug addressregisters for storing code breakpoints representing addresses of preselectedinstructions, and two digital comparators. During the instruction prefetch phase ofoperation, the first comparator compares the 29 most significant bits [31:3] of the 32-bitprefetch instruction address against the code breakpoints stored in the debug addressregisters and produces a 1-bit signal indicating whether such comparison results in apositive match. Subsequently, during the decode phase of operation, the secondcomparator compares the three least significant bits [2:0] of the 32-bit prefetchinstruction address and produces a 1-bit signal indicating whether such comparisonresults in a positive match. These two 1-bit signals are then logically ANDed,

synchronized with bit 3 [2] of the 32-bit prefetch instruction address to ensure that suchtwo 1-bit signals are based upon corresponding comparisons of the same prefetchinstruction address.

申请人：NATIONAL SEMICONDUCTOR CORPORATION

代理机构：Limbach & Limbach LP.

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