Legacy Document

Important: The information in this document is obsolete and should not be used for new development.

Inside Macintosh: QuickDraw GX Environment and Utilities /

Chapter 8 - QuickDraw GX Mathematics / QuickDraw GX Mathematics Reference

Mathematical Functions / Bit Analysis

FirstBit
You can use the FirstBit function to determine the highest order bit that is set in a number.
short FirstBit (unsigned long x);
x
The number for which the first bit is to be determined.

function result
The bit number of the highest order bit of the number in the argument.

DESCRIPTION
The FirstBit function returns the bit number of the highest order bit in a number that is set, or -1 if the number is 0. The highest-order bit is bit 31; the lowest-order bit is bit 0.

DESCRIPTION
The use of the FirstBit function is described in the section "Analyzing the Bits in a Number" on page 8-33.