Abstract: A method and apparatus for concurrent testing of a plurality of microprocessors, each of which may have a different revision, by creating an abstract base class which specifies the names of a plurality of tests, creating a derived class for each revision and defining each of the tests appropriately for each of the derived classes, instantiating an object from one of the derived classes for each of the microprocessors and executing the tests by reference to the objects. A computer system is configured to be coupled to the microprocessors and, upon execution of a debug/test application on the computer system, the revision of each microprocessor is determined and an object is instantiated from the derived class corresponding to the revision. Each object is thereby dynamically bound to the tests defined for the derived class corresponding to the revision, and references to the tests via the objects automatically execute the test code specific to appropriate revision of the microprocessor.

Abstract: A method and system for testing a plurality of addressing modes in a microprocessor comprising executing a test instruction which is stored in memory, subsequently overwriting the test instruction in memory and then re-executing the test instruction. The test instruction is stored at a memory location which is within a code segment. A data segment is defined to overlap with the code segment and a portion of the test instruction is overwritten by storing data within the overlapping data segment. The overwritten portion of the test instruction identifies the addressing mode of the test instruction and the stored data represents the next addressing mode to be tested. In an x86 architecture, the overwritten portion of the test instruction may comprise a MODR/M byte and an SIB byte, each of which may take on values from 00 to ff (hexadecimal). The addressing modes of the microprocessor may therefore be tested by sequentially incrementing the MODR/M and SIB bytes and executing the test instruction.

Abstract: A method and system for verifying the accuracy of trace data generated by execution of a program on a computer under test, one embodiment of the method comprising scanning the trace data to locate bitmap data corresponding to series of consecutive conditional branches and comparing the number of bits representative of these branches to the number of consecutive conditional branches in the instruction sequence. The trace data includes address entries and bitmap entries. The trace data is scanned in reverse chronological order beginning with the most recent entry to locate an address entry preceding one or more bitmaps which represent a most recent series of conditional branches. Beginning with the instruction at the address contained in the address entry, the program instructions are scanned in program order until a conditional branch is encountered. The branch is counted and the trace data is examined to determine whether the branch was taken and scanning is resumed.

Abstract: A method and system for determining the sequence of execution of instructions in a computer under test using trace data generated upon execution of certain ones of the instructions. In one embodiment, the method comprises locating an initial entry in the trace data and scanning the instructions in program order beginning with an instruction indicated by the initial entry. When a branch instruction is encountered, the trace data is examined to determine the subsequently executed instruction. If the branch is unconditional, a corresponding address entry in the trace data indicates the address of the next instruction. If the branch is conditional, a corresponding bitmap entry in the trace data contains a bit which indicates whether the branch was taken. From this bit and the instructions themselves, the next instruction is determined.

Abstract: A method and system for testing a plurality of addressing modes in a microprocessor comprising executing a test instruction which is stored in memory, subsequently overwriting the test instruction in memory and then re-executing the test instruction. The test instruction is stored at a memory location which is within a code segment. A data segment is defined to overlap with the code segment and a portion of the test instruction is overwritten by storing data within the overlapping data segment. The overwritten portion of the test instruction identifies the addressing mode of the test instruction and the stored data represents the next addressing mode to be tested. In an x86 architecture, the overwritten portion of the test instruction may comprise a MODR/M byte and an SIB byte, each of which may take on values from 00 to ff (hexadecimal). The addressing modes of the microprocessor may therefore be tested by sequentially incrementing the MODR/M and SIB bytes and executing the test instruction.

Abstract: A computing system and bus bridge in which the bus bridge includes a buffer pool wherein the storage buffers contained in the buffer pool may be allocated as post buffers or fetch buffers in response to appropriate requests from the bus bridge. In the preferred embodiment, the bus bridge includes a buffer pool control unit adapted to temporarily allocate any of the plurality of storage buffers as either a post buffer or a fetch buffer depending upon the system requirements. Broadly speaking, the present invention contemplates a computing system including a first component connected to a first bus, a second component connected to a second bus, and a bus bridge connected to a first and second busses. The bus bridge includes a buffer pool comprised of a plurality of storage buffers and a buffer pool control unit that is capable of temporarily allocating at least one of the storage buffers as either a post buffer or a fetch buffer in response to system requirement.

Abstract: A cache memory system comprising a first bus for connecting to a bus master and a second bus for connecting to a system memory. The system memory comprises a plurality of cacheable memory locations. A bus bridge provides an interface between the first bus and the second bus. A cache memory controller for caching data stored in the cacheable memory locations is connected to the system memory. The cache memory controller includes a snoop control circuit directly coupled to the first bus for snooping bus transactions upon the first bus and further coupled to the second bus for snooping bus transactions on said second bus.