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Bit Operations



 
Boolean TestAndSet(

                     UInt32 bit

                     UInt8 *startAddress);



 
Boolean TestAndClear(

                     UInt32 bit

                     UInt8 *startAddress);

--> bit: The bit number in the range 0 through 7.
--> startAddress: The address of the byte in which the bit is located.

DESCRIPTION

TestAndSet sets and TestAndClear clears a single bit in a byte at a specified address. They return true if the bit was already set or cleared respectively and false otherwise.

EXECUTION CONTEXT

TestAndSet and TestAndClear may be called from task level, secondary interrupt level, or hardware interrupt level.