BTOP(9F) Kernel Functions for Drivers BTOP(9F)

NAME

btop - convert size in bytes to size in pages (round down)

SYNOPSIS

#include <sys/ddi.h>


unsigned long btop(unsigned long numbytes);

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

PARAMETERS

numbytes
Number of bytes.

DESCRIPTION

The btop() function returns the number of memory pages that are contained
in the specified number of bytes, with downward rounding in the case that
the byte count is not a page multiple. For example, if the page size is
2048, then btop(4096) returns 2, and btop(4097) returns 2 as well.
btop(0) returns 0.

RETURN VALUES

The return value is always the number of pages. There are no invalid
input values, and therefore no error return values.

CONTEXT

The btop() function can be called from user, interrupt, or kernel
context.

SEE ALSO

btopr(9F), ddi_btop(9F), ptob(9F)


Writing Device Drivers

January 16, 2006 BTOP(9F)