Legacy Document

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.