---
name: "bios"
section: "9"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/bios/9"
---

# bios(9)

interact with PC BIOS

## NAME

**bios\_sigsearch**, **bios32\_SDlookup**, **bios32** – interact with PC BIOS

## SYNOPSIS

**#include \<sys/param.h\>**

**#include \<vm/vm.h\>**

**#include \<vm/pmap.h\>**

**#include \<machine/param.h\>**

**#include \<machine/pmap.h\>**

**#include \<machine/pc/bios.h\>**

*u\_int32\_t*\

**bios\_sigsearch**(*u\_int32\_t start*, *u\_char \*sig*, *int siglen*, *int paralen*, *int sigofs*);

*int*\

**bios32\_SDlookup**(*struct bios32\_SDentry \*ent*);

*int*\

**bios32**(*struct bios\_regs \*br*, *u\_int offset*, *u\_short segment*);

**BIOS\_PADDRTOVADDR**(*addr*);

**BIOS\_VADDRTOPADDR**(*addr*); *extern* *struct* *bios32\_SDentry* *PCIbios*; *extern* *struct* *SMBIOS\_table* *SMBIOStable*; *extern* *struct* *DMI\_table* *DMItable*;

## DESCRIPTION

These functions provide a general-purpose interface for dealing with the BIOS functions and data encountered on x86 PC-architecture systems.

- **bios\_sigsearch**()

  Searches the BIOS address space for a service signature, usually an uppercase ASCII sequence surrounded by underscores. The search begins at *start*, or at the beginning of the BIOS if *start* is zero. *siglen* bytes of the BIOS image and *sig* are compared at *sigofs* bytes offset from the current location. If no match is found, the current location is incremented by *paralen* bytes and the search repeated. If the signature is found, its effective physical address is returned. If no signature is found, zero is returned.

- **BIOS\_VADDRTOPADDR**()

  Returns the effective physical address which corresponds to the kernel virtual address *addr*.

- **BIOS\_PADDRTOVADDR**()

  Returns the kernel virtual address which corresponds to the effective physical address *addr*.

- SMBIOStable

  If not NULL, points to a *struct* *SMBIOS\_table* structure containing information read from the System Management BIOS table during system startup.

- DMItable

  If not NULL, points to a *struct* *DMI\_table* structure containing information read from the Desktop Management Interface parameter table during system startup.

## BIOS32

At system startup, the BIOS is scanned for the BIOS32 Service Directory (part of the PCI specification), and the existence of the directory is recorded. This can then be used to locate other services.

- **bios32\_SDlookup**()

  Attempts to locate the BIOS32 service matching the 4-byte identifier passed in the *ident* field of the *ent* argument.

- **bios32**()

  Calls a bios32 function. This presumes that the function is capable of working within the kernel segment (normally the case). The virtual address of the entrypoint is supplied in *entry* and the register arguments to the function are supplied in *args*.

- PCIbios

  If not NULL, points to a *struct* *bios32\_SDentry* structure describing the PCI BIOS entrypoint which was found during system startup.