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Inside Macintosh: Operating System Utilities /
Chapter 3 - Mathematical and Logical Utilities / Mathematical and Logical Utilities Reference
Routines / Testing and Setting Bits


You can use the BitSet procedure to set a particular bit.

PROCEDURE BitSet (bytePtr: Ptr; bitNum: LongInt);
A pointer to a byte in memory.
The bit to be set, specified as a positive offset from the high-order bit of the byte pointed to by the bytePtr parameter. The bit being set need not be in the byte pointed to by bytePtr.
The BitSet procedure sets (to a value of 1) the bit specified by the bytePtr and bitNum parameters.

The bit-numbering scheme used by the BitSet procedure is the opposite of MC680x0 bit numbering. To convert an MC680x0 bit number to the format required by the BitSet procedure, subtract the MC680x0 bit number from the highest bit number.

For an example of the use of the BitSet procedure, see page 3-16. For more information about reversed bit-numbering see "Reversed Bit-Numbering" on page 3-7.

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6 JUL 1996

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