| 摘要 |
A system, method, and computer readable medium allow for granting permission to modify a memory area, such as a data variable stored in memory, without using valuable memory space to store permission variables. Rather than using separate permission variables, a portion of a data variable is used to indicate whether or not the data variable may be modified. The least significant bit of a variable (i.e. memory area) is used as a permission indicator. When the least significant bit is set to one, it is permissible to modify the variable. When the least significant bit is set to zero, it is not permissible to modify the variable. In one embodiment of the present invention, a counter variable is both checked for permission to increment, and incremented (if permission is granted) in one step. Efficiency is increased, which is especially valuable in the case of embedded systems, where memory space is typically in short supply. Because valuable memory space is conserved, more data may be stored in memory, and thus more data functions may be implemented in the embedded system. Further, because permission to modify a data variable is contained within the data variable itself, a program which desires to modify the data variable does not need to reference a permission, or locking, variable and test for permission to modify the data variable.
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