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.\" Copyright (c) 1997 Michael Smith
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.Dd August 1, 1997
.Dt BIOS 9
.Os FreeBSD
.Sh NAME
.Nm bios_sigsearch , 
.Nm bios32_SDlookup ,
.Nm bios32
.Nd interact with PC BIOS
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <machine/pc/bios.h>
.Ft u_int32_t
.Fn bios_sigsearch "u_int32_t start" "u_char *sig" "int siglen" "int paralen" "int sigofs"
.Ft int
.Fn bios32_SDlookup "struct bios32_SDentry *ent"
.Ft void
.Fn bios32 "caddr_t entry" "struct bios32_args *args"
.Fn BIOS_PADDRTOVADDR "addr"
.Fn BIOS_VADDRTOPADDR "addr"
.Vt extern struct bios32_SDentry PCIbios ;
.Vt extern struct SMBIOS_table SMBIOStable ;
.Vt extern struct DMI_table DMItable ;
.Sh DESCRIPTION
These functions provide a general-purpose interface for dealing with
the BIOS functions and data encountered on x86 PC-architecture systems.
.Bl -tag -width 20n
.It Fn bios_sigsearch
Searches the BIOS address space for a service signature, usually an
uppercase ASCII sequence surrounded by underscores.  The search begins
at
.Fa start ,
or at the beginning of the BIOS if
.Fa start
is zero.
.Fa siglen
bytes of the BIOS image and
.Fa sig
are compared at
.Fa sigofs
bytes offset from the current location.  If no match is found, the 
current location is incremented by
.Fa 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.
.It Fn BIOS_VADDRTOPADDR
Returns the effective physical address which corresponds to the kernel
virtual address
.Fa addr .
.It Fn BIOS_VADDRTOPADDR
Returns the kernel virtual address which corresponds to the effective
physical address
.Fa addr .
.It SMBIOStable
If not NULL, points to a
.Ft struct SMBIOS_table
structure containing information read from the System Management BIOS table 
during system startup.
.It DMItable
If not NULL, points to a
.Ft struct DMI_table
structure containing information read from the Desktop Management Interface
parameter table during system startup.
.El
.Sh 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.
.Bl -tag -width 20n
.It Fn bios32_SDlookup
Attempts to locate the BIOS32 service matching the 4-byte identifier
passed in the
.Fa ident
field of the
.Fa ent
argument.
.It Fn 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
.Fa entry
and the register arguments to the function are supplied in
.Fa args .
.It PCIbios
If not NULL, points to a
.Ft struct bios32_SDentry
structure describing the PCI BIOS entrypoint which was found during system
startup.
.El