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     bios_sigsearch, bios32_SDlookup, bios32, bios_oem_strings — interact with
     PC BIOS


     #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>

     bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen,
         int sigofs);

     bios32_SDlookup(struct bios32_SDentry *ent);

     bios32(struct bios_regs *br, u_int offset, u_short segment);



     extern struct bios32_SDentry PCIbios;
     extern struct SMBIOS_table SMBIOStable;
     extern struct DMI_table DMItable;

     bios_oem_strings(struct bios_oem *oem, u_char *buffer, size_t maxlen);

     struct bios_oem_signature {
             char * anchor;          /* search anchor string in BIOS memory */
             size_t offset;          /* offset from anchor (may be negative) */
             size_t totlen;          /* total length of BIOS string to copy */
     struct bios_oem_range {
             u_int from;             /* shouldn't be below 0xe0000 */
             u_int to;               /* shouldn't be above 0xfffff */
     struct bios_oem {
             struct bios_oem_range range;
             struct bios_oem_signature signature[];


     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_oem_strings()    Searches a given BIOS memory range for one or more
                           strings, and composes a printable concatenation of
                           those found.  The routine expects a structure
                           describing the BIOS address range (within 0xe0000 -
                           0xfffff), and a { NULL, 0, 0 } -terminated array of
                           bios_oem_signature structures which define the
                           anchor string, an offset from the beginning of the
                           match (which may be negative), and totlen number of
                           bytes to be collected from BIOS memory starting at
                           that offset.  Unmatched anchors are ignored,
                           whereas matches are copied from BIOS memory
                           starting at their corresponding offset with
                           unprintable characters being replaced with space,
                           and consecutive spaces being suppressed.  This
                           composed string is stored in buffer up to the given
                           maxlen bytes (including trailing ‘\0’, and any
                           trailing space surpressed).  If an error is
                           encountered, i.e. trying to read out of said BIOS
                           range, other invalid input, or buffer overflow, a
                           negative integer is returned, otherwise the length
                           of the composed string is returned.  In particular,
                           a return value of 0 means that none of the given
                           anchor strings were found in the specified BIOS
                           memory range.

     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


     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

     PCIbios               If not NULL, points to a struct bios32_SDentry
                           structure describing the PCI BIOS entrypoint which
                           was found during system startup.