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