reactos/boot/freeldr/freeldr/arch/i386/pcrtc.c

93 lines
2.7 KiB
C

/*
* FreeLoader
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <freeldr.h>
#define BCD_INT(bcd) (((bcd & 0xf0) >> 4) * 10 + (bcd &0x0f))
TIMEINFO*
PcGetTime(VOID)
{
static TIMEINFO TimeInfo;
REGS Regs;
for (;;)
{
/* Some BIOSes, such as the 1998/07/25 system ROM
* in the Compaq Deskpro EP/SB, leave CF unchanged
* if successful, so CF should be cleared before
* calling this function. */
Regs.x.eflags = 0;
// __writeeflags(__readeflags() & ~EFLAGS_CF);
/* Int 1Ah AH=04h
* TIME - GET REAL-TIME CLOCK DATE (AT,XT286,PS)
*
* AH = 04h
* CF clear to avoid bug
* Return:
* CF clear if successful
* CH = century (BCD)
* CL = year (BCD)
* DH = month (BCD)
* DL = day (BCD)
* CF set on error
*/
Regs.b.ah = 0x04;
Int386(0x1A, &Regs, &Regs);
if (!INT386_SUCCESS(Regs)) continue;
TimeInfo.Year = 100 * BCD_INT(Regs.b.ch) + BCD_INT(Regs.b.cl);
TimeInfo.Month = BCD_INT(Regs.b.dh);
TimeInfo.Day = BCD_INT(Regs.b.dl);
/* Some BIOSes leave CF unchanged if successful,
* so CF should be cleared before calling this function. */
Regs.x.eflags = 0;
// __writeeflags(__readeflags() & ~EFLAGS_CF);
/* Int 1Ah AH=02h
* TIME - GET REAL-TIME CLOCK TIME (AT,XT286,PS)
*
* AH = 02h
* CF clear to avoid bug
* Return:
* CF clear if successful
* CH = hour (BCD)
* CL = minutes (BCD)
* DH = seconds (BCD)
* DL = daylight savings flag (00h standard time, 01h daylight time)
* CF set on error (i.e. clock not running or in middle of update)
*/
Regs.b.ah = 0x02;
Int386(0x1A, &Regs, &Regs);
if (!INT386_SUCCESS(Regs)) continue;
TimeInfo.Hour = BCD_INT(Regs.b.ch);
TimeInfo.Minute = BCD_INT(Regs.b.cl);
TimeInfo.Second = BCD_INT(Regs.b.dh);
break;
}
return &TimeInfo;
}
/* EOF */