[SOLVED] CS代考计算机代写 #include “devices/speaker.h”

#include “devices/speaker.h”
#include “devices/pit.h”
#include “threads/io.h”
#include “threads/interrupt.h”
#include “devices/timer.h”

/* Speaker port enable I/O register. */
#define SPEAKER_PORT_GATE0x61

/* Speaker port enable bits. */
#define SPEAKER_GATE_ENABLE0x03

/* Sets the PC speaker to emit a tone at the given FREQUENCY, in
Hz. */
void
speaker_on (int frequency)
{
if (frequency >= 20 && frequency <= 20000){/* Set the timer channel that’s connected to the speaker to output a square wave at the given FREQUENCY, then connect the timer channel output to the speaker. */enum intr_level old_level = intr_disable ();pit_configure_channel (2, 3, frequency);outb (SPEAKER_PORT_GATE, inb (SPEAKER_PORT_GATE) | SPEAKER_GATE_ENABLE);intr_set_level (old_level);}else{/* FREQUENCY is outside the range of normal human hearing. Just turn off the speaker. */speaker_off ();}}/* Turn off the PC speaker, by disconnecting the timer channel’s output from the speaker. */voidspeaker_off (void){enum intr_level old_level = intr_disable ();outb (SPEAKER_PORT_GATE, inb (SPEAKER_PORT_GATE) & ~SPEAKER_GATE_ENABLE);intr_set_level (old_level);}/* Briefly beep the PC speaker. */voidspeaker_beep (void){/* Only attempt to beep the speaker if interrupts are enabled, because we don’t want to freeze the machine during the beep. We could add a hook to the timer interrupt to avoid that problem, but then we’d risk failing to ever stop the beep if Pintos crashes for some unrelated reason.There’s nothing more annoying than a machine whose beeping you can’t stop without a power cycle. We can’t just enable interrupts while we sleep.For one thing, we get called (indirectly) from printf, which should always work, even during boot before we’re ready to enable interrupts. */if (intr_get_level () == INTR_ON){speaker_on (440);timer_msleep (250);speaker_off ();}}