#include #include #include #include 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); }