void
bioscall(
int function
, struct bioscallregs *regs
)
function
,
and returns to protected mode.
This function is intended to be called during the initial system bootstrap when necessary to probe devices or pseudo-devices.
The register values specified by
*regs
(with one exception) are installed before the BIOS interrupt is called.
The processor flags are handled specially. Only the following flags are
passed to the
BIOS from the registers in
regs
(the remainder come from the processor's flags register at the time
of the call):
PSL_C,
PSL_PF,
PSL_AF,
PSL_Z,
PSL_N,
PSL_D,
PSL_V.
The bioscallregs structure is defined to contain structures for each register, to allow access to 32-, 16- or 8-bit wide sections of the registers. Definitions are provided which simplify access to the union members.
*regs
with the processor registers as returned from the BIOS call.
ax
and
bx
,
then calls the BIOS to fetch the details for calling the APM support
through a protected-mode interface. The BIOS returns these details in
the registers:
regs.AX = APM_BIOS_FN(APM_INSTALLATION_CHECK);
regs.BX = APM_DEV_APM_BIOS;
regs.CX = regs.DX = 0;
regs.ESI = regs.EDI = regs.EFLAGS = 0;
bioscall(APM_SYSTEM_BIOS, ®s);
#include <i386/bioscall.h>
#include <i386/apmvar.h>
struct bioscallregs regs;
sys/arch/i386/i386/bioscall.s
,
sys/arch/i386/bioscall/biostramp.S