Manual browser: powerof2(9)
|ROUNDUP(9)||Kernel Developer's Manual||ROUNDUP(9)|
NAMEroundup — macros for counting and rounding
DESCRIPTIONThe roundup() and rounddown() macros return an integer from rounding x up and down, respectively, to the next size. The howmany() macro in turn reveals how many times size fits into x, rounding the residual up.
The roundup2() macro also rounds up, but with the assumption that size is a power of two. If x is indeed a power of two, powerof2() return 1.
RETURN VALUESThe return value is an integer from the respective operation. If x is 0, all macros except powerof2() return 0. The behavior is undefined if size is 0.
EXAMPLESThe following example rounds the variable rx to a 32-bit boundary:
uint16_t rx; ... rx = roundup2(rx, sizeof(uint32_t));
CAVEATSAll described macros make no assumptions about the type of the parameters. These are implicitly assumed to be unsigned integers.
|June 1, 2011||NetBSD 7.0|