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#ifndef GRUB_SPEAKER_HEADER
#define GRUB_SPEAKER_HEADER 1
#include <grub/cpu/io.h>
#include <grub/i386/pit.h>
/* The frequency of the PIT clock. */
#define GRUB_SPEAKER_PIT_FREQUENCY 0x1234dd
static inline void
grub_speaker_beep_off (void)
{
unsigned char status;
status = grub_inb (GRUB_PIT_SPEAKER_PORT);
grub_outb (status & ~(GRUB_PIT_SPK_TMR2 | GRUB_PIT_SPK_DATA),
GRUB_PIT_SPEAKER_PORT);
}
static inline void
grub_speaker_beep_on (grub_uint16_t pitch)
{
unsigned char status;
unsigned int counter;
if (pitch < 20)
pitch = 20;
else if (pitch > 20000)
pitch = 20000;
counter = GRUB_SPEAKER_PIT_FREQUENCY / pitch;
/* Program timer 2. */
grub_outb (GRUB_PIT_CTRL_SELECT_2
| GRUB_PIT_CTRL_READLOAD_WORD
| GRUB_PIT_CTRL_SQUAREWAVE_GEN
| GRUB_PIT_CTRL_COUNT_BINARY, GRUB_PIT_CTRL);
grub_outb (counter & 0xff, GRUB_PIT_COUNTER_2); /* LSB */
grub_outb ((counter >> 8) & 0xff, GRUB_PIT_COUNTER_2); /* MSB */
/* Start speaker. */
status = grub_inb (GRUB_PIT_SPEAKER_PORT);
grub_outb (status | GRUB_PIT_SPK_TMR2 | GRUB_PIT_SPK_DATA,
GRUB_PIT_SPEAKER_PORT);
}
#endif
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