49 lines
1.7 KiB
C
49 lines
1.7 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2008 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/types.h>
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#include <grub/i386/io.h>
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#include <grub/i386/pit.h>
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void
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grub_pit_wait (grub_uint16_t tics)
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{
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/* Disable timer2 gate and speaker. */
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grub_outb (grub_inb (GRUB_PIT_SPEAKER_PORT)
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& ~ (GRUB_PIT_SPK_DATA | GRUB_PIT_SPK_TMR2),
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GRUB_PIT_SPEAKER_PORT);
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/* Set tics. */
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grub_outb (GRUB_PIT_CTRL_SELECT_2 | GRUB_PIT_CTRL_READLOAD_WORD,
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GRUB_PIT_CTRL);
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grub_outb (tics & 0xff, GRUB_PIT_COUNTER_2);
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grub_outb (tics >> 8, GRUB_PIT_COUNTER_2);
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/* Enable timer2 gate, keep speaker disabled. */
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grub_outb ((grub_inb (GRUB_PIT_SPEAKER_PORT) & ~ GRUB_PIT_SPK_DATA)
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| GRUB_PIT_SPK_TMR2,
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GRUB_PIT_SPEAKER_PORT);
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/* Wait. */
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while ((grub_inb (GRUB_PIT_SPEAKER_PORT) & GRUB_PIT_SPK_TMR2_LATCH) == 0x00);
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/* Disable timer2 gate and speaker. */
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grub_outb (grub_inb (GRUB_PIT_SPEAKER_PORT)
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& ~ (GRUB_PIT_SPK_DATA | GRUB_PIT_SPK_TMR2),
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GRUB_PIT_SPEAKER_PORT);
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}
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