BIOSCALL(9) | Kernel Developer's Manual (i386) | BIOSCALL(9) |
bioscall
—
#include <i386/bioscall.h>
void
bioscall
(int
function, struct
bioscallregs *regs);
bioscall
() function switches the processor into real
mode, calls the BIOS interrupt numbered 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.
bioscall
() function fills in
*regs with the processor registers as returned from the
BIOS call.
bioscall
() by
setting up a register structure with the APM installation check and device
types in registers 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:
#include <i386/bioscall.h> #include <i386/apmvar.h> struct bioscallregs regs; 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);
bioscall
() function first appeared in
NetBSD 1.3.
May 5, 2010 | NetBSD 9.2 |