40 lines
1.5 KiB
C
40 lines
1.5 KiB
C
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/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (c) 2011 Michael Sevakis
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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/* Actually output samples into beep_buf */
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static FORCE_INLINE void beep_generate(uint32_t *out, int count,
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int32_t *phase, uint32_t step,
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uint32_t amplitude)
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{
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uint32_t s;
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asm volatile (
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"1: \n"
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"eor %3, %5, %1, asr #31 \n"
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"subs %2, %2, #1 \n"
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"str %3, [%0], #4 \n"
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"add %1, %1, %4 \n"
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"bgt 1b \n"
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: "+r"(out), "+r"(*phase), "+r"(count),
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"=&r"(s)
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: "r"(step), "r"(amplitude));
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}
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