ladybird/Kernel/Devices/PCSpeaker.cpp
Brian Gianforcaro 1682f0b760 Everything: Move to SPDX license identifiers in all files.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.

See: https://spdx.dev/resources/use/#identifiers

This was done with the `ambr` search and replace tool.

 ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 11:22:27 +02:00

26 lines
608 B
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Arch/x86/CPU.h>
#include <Kernel/Devices/PCSpeaker.h>
#include <Kernel/IO.h>
#include <Kernel/Time/PIT.h>
void PCSpeaker::tone_on(int frequency)
{
IO::out8(PIT_CTL, TIMER2_SELECT | WRITE_WORD | MODE_SQUARE_WAVE);
u16 timer_reload = BASE_FREQUENCY / frequency;
IO::out8(TIMER2_CTL, LSB(timer_reload));
IO::out8(TIMER2_CTL, MSB(timer_reload));
IO::out8(0x61, IO::in8(0x61) | 3);
}
void PCSpeaker::tone_off()
{
IO::out8(0x61, IO::in8(0x61) & ~3);
}