Appeal No. 1995-3690 Page 8
Application No. 08/000,342
trapped. If no trap has occurred, the stores in the shadow
buffer are committed to memory (specification at page 17).
After the execution of the tagged speculative instruction, the
program proceeds to the next instruction which would have
followed the tagged instructions at its origin point.
If a trap has occurred, the trap handler uses the address
of the checkpoint instruction to find the beginning of the
associated block with the trapped instruction. It adds the
issue counter value to this address to find the instruction
which trapped (specification at page 22). A flush instruction
clears the buffer memory after the stores in the buffer memory
are committed to memory or if the program takes a direction
not leading to the origin point of the tagged instructions
(specification at pages 4, and 18 to 19).
From the foregoing, it is our view that the specification
is clear on how tags are utilized to generate a precise
interrupt.
The program utilizes the address of the checkpoint instruction
(which takes a specific tag as an argument) to find the
address of the trapped instruction. In addition, the tagged
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