kernel/drivers/rdpcclk.asm

54 lines
1.5 KiB
NASM

;
; File:
; rdpcclk.asm
; Description:
; read the PC style clock from bios
;
; Copyright (c) 1995
; Pasquale J. Villani
; All Rights Reserved
;
; This file is part of DOS-C.
;
; DOS-C 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, or (at your option) any later version.
;
; DOS-C 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 DOS-C; see the file COPYING. If not,
; write to the Free Software Foundation, 675 Mass Ave,
; Cambridge, MA 02139, USA.
;
; $Header$
;
%include "../kernel/segs.inc"
segment HMA_TEXT
;
; ULONG ReadPCClock(void)
;
global READPCCLOCK
READPCCLOCK:
mov ah,0
int 1ah
extern _DaysSinceEpoch ; ; update days if necessary
; (ah is still 0, al contains midnight flag)
add word [_DaysSinceEpoch ],ax ; *some* BIOSes accumulate several days
adc word [_DaysSinceEpoch+2],byte 0;
; set return value dx:ax
xchg ax,cx ; ax=_cx, cx=_ax
xchg ax,dx ; dx=_cx, ax=_dx (cx=_ax)
ret