ACPI Namespace Reference

Abstracts the ACPI standard that provides interfaces for hardware detection, device configuration, and energy management. More...

Classes
struct	Address
	ACPI address format. More...

Enumerations
enum class	AddressSpace : uint8_t {   MEMORY = 0x0 ,   IO = 0x1 }

Functions
bool	init ()
	Initialize the ACPI description table. More...
unsigned	count ()
	Number of entries in the description table.
SDTH *	get (unsigned num)
	Get entry of description table by index. More...
SDTH *	get (char a, char b, char c, char d)
	Get entry of description table by four character identifier. More...
int	revision ()
	Retrieve the revision from the Root System Description Pointer (RSDP)

Constants
const char *	RSDP_SIGNATURE = "RSD PTR "

Detailed Description

Abstracts the ACPI standard that provides interfaces for hardware detection, device configuration, and energy management.

ACPI is the successor to APM (Advanced Power Management), aiming to give the operating system more control over the hardware. This extended control, for instance, enables the operating system to assign a particular amount of energy to every device (e.g., by disabling a device or changing to standby mode). For this purpose, BIOS and chipset provide a set of tables that describe the system and its components and provide routines the OS can call. These tables contain details about the system, such as the number of CPU cores and the LAPIC/IOAPIC, which are determined during system boot.

Function Documentation

init()

bool ACPI::init

(

)

Initialize the ACPI description table.

Searches physical memory ranges o 16-byte boundaries for a valid Root System Description Pointer (RSDP) structure signature and checksum. If present, the superseding Extended System Description Table (XSDT) is used.

See also

ACPI-Specification 5.2.5 Root System Description Pointer (RSDP)

ACPI-Specification 5.2.8 Extended System Description Table (XSDT)

get() [1/2]

SDTH * ACPI::get

(

unsigned

num

)

Get entry of description table by index.

Parameters

num	index in description table

Returns

Pointer to corresponding entry or nullptr if not available

get() [2/2]

SDTH * ACPI::get	(	char	a,
		char	b,
		char	c,
		char	d
	)

Get entry of description table by four character identifier.

Parameters

a	first character of identifier
b	second character of identifier
c	third character of identifier
d	forth and last character of identifier

Returns

Pointer to corresponding entry or nullptr if not available