A method and apparatus for implementing check instructions that allow for the reuse of memory conflict information if no memory conflict occurs

摘要

A method and apparatus for implementing check instructions that allow for the reuse of memory conflict information if no memory conflict occurs. According to one aspect of the invention, a machine-readable medium having stored thereon data representing sequences of instructions is described. When executed by a computer system, the sequences of instructions cause the computer system to perform a series of steps. One of these steps involves preloading one of a set of registers data retrieved from a memory starting at a first address. Another of these steps involves storing memory conflict information representing the first address. This memory conflict information is later used for determining if a memory conflict has occurred. Another of these steps involves storing data at a second address in the memory. Yet another of these steps involves determining if a memory conflict has occurred between the first address and the second address using the previously stored memory conflict information. If a memory conflict occurred between the first and second addresses, then one of the registers is reloaded with the data located at the first address. However, if a memory conflict did not occur between the first and second addresses, then the memory conflict information is left for use during subsequent memory conflict checks. According to one embodiment of the invention, the data is reloaded into a register by causing the computer system to branch to recovery code. According to another embodiment of the invention, the data is reloaded into a register without performing any branch instructions.