mirror of
https://github.com/reactos/reactos.git
synced 2024-06-25 15:31:47 +00:00
91 lines
2.5 KiB
C
91 lines
2.5 KiB
C
/*
|
|
* FreeLoader
|
|
* Copyright (C) 1998-2003 Brian Palmer <brianp@sginet.com>
|
|
*
|
|
* 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>
|
|
|
|
void sound(int freq);
|
|
void delay(unsigned msec);
|
|
|
|
VOID PcBeep(VOID)
|
|
{
|
|
sound(700);
|
|
delay(200);
|
|
sound(0);
|
|
}
|
|
|
|
void delay(unsigned msec)
|
|
{
|
|
REGS Regs;
|
|
unsigned usec;
|
|
unsigned msec_this;
|
|
|
|
// Int 15h AH=86h
|
|
// BIOS - WAIT (AT,PS)
|
|
//
|
|
// AH = 86h
|
|
// CX:DX = interval in microseconds
|
|
// Return:
|
|
// CF clear if successful (wait interval elapsed)
|
|
// CF set on error or AH=83h wait already in progress
|
|
// AH = status (see #00496)
|
|
|
|
// Note: The resolution of the wait period is 977 microseconds on
|
|
// many systems because many BIOSes use the 1/1024 second fast
|
|
// interrupt from the AT real-time clock chip which is available on INT 70;
|
|
// because newer BIOSes may have much more precise timers available, it is
|
|
// not possible to use this function accurately for very short delays unless
|
|
// the precise behavior of the BIOS is known (or found through testing)
|
|
|
|
while (msec)
|
|
{
|
|
msec_this = msec;
|
|
|
|
if (msec_this > 4000)
|
|
{
|
|
msec_this = 4000;
|
|
}
|
|
|
|
usec = msec_this * 1000;
|
|
|
|
Regs.b.ah = 0x86;
|
|
Regs.w.cx = usec >> 16;
|
|
Regs.w.dx = usec & 0xffff;
|
|
Int386(0x15, &Regs, &Regs);
|
|
|
|
msec -= msec_this;
|
|
}
|
|
}
|
|
|
|
void sound(int freq)
|
|
{
|
|
int scale;
|
|
|
|
if (freq == 0)
|
|
{
|
|
WRITE_PORT_UCHAR((PUCHAR)0x61, READ_PORT_UCHAR((PUCHAR)0x61) & ~3);
|
|
return;
|
|
}
|
|
|
|
scale = 1193046 / freq;
|
|
WRITE_PORT_UCHAR((PUCHAR)0x43, 0xb6);
|
|
WRITE_PORT_UCHAR((PUCHAR)0x42, scale & 0xff);
|
|
WRITE_PORT_UCHAR((PUCHAR)0x42, scale >> 8);
|
|
WRITE_PORT_UCHAR((PUCHAR)0x61, READ_PORT_UCHAR((PUCHAR)0x61) | 3);
|
|
}
|