New terminal outputs using serial: morse and spkmodem.

include/grub/speaker.h

@@ -0,0 +1,47 @@
+#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