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| author | Michael Sevakis <jethead71@rockbox.org> | 2011-12-04 18:19:39 +0000 |
|---|---|---|
| committer | Michael Sevakis <jethead71@rockbox.org> | 2011-12-04 18:19:39 +0000 |
| commit | a43df152c2adf737208bbeb294a0a13608d3cc43 (patch) | |
| tree | c0534198745141699a08d9471303744948e51138 /firmware/export | |
| parent | 700e360b612766eb2729597be55c43b5b69bbe7f (diff) | |
| download | rockbox-a43df152c2adf737208bbeb294a0a13608d3cc43.zip rockbox-a43df152c2adf737208bbeb294a0a13608d3cc43.tar.gz rockbox-a43df152c2adf737208bbeb294a0a13608d3cc43.tar.bz2 rockbox-a43df152c2adf737208bbeb294a0a13608d3cc43.tar.xz | |
Collect the 16-bit signed range sample clipping routines scattered about, which can be optimized on armv6 and create firmware/export/dsp-util.h (for lack of better place right now).
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31142 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/export')
| -rw-r--r-- | firmware/export/dsp-util.h | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/firmware/export/dsp-util.h b/firmware/export/dsp-util.h new file mode 100644 index 0000000..76962b5 --- /dev/null +++ b/firmware/export/dsp-util.h @@ -0,0 +1,51 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2011 by Michael Sevakis + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ +#ifndef DSP_HELPER_H +#define DSP_HELPER_H + +/** Clip sample to signed 16 bit range **/ + +#ifdef CPU_ARM +#if ARM_ARCH >= 6 +static FORCE_INLINE int32_t clip_sample_16(int32_t sample) +{ + int32_t out; + asm ("ssat %0, #16, %1" + : "=r" (out) : "r"(sample)); + return out; +} +#define CLIP_SAMPLE_16_DEFINED +#endif /* ARM_ARCH */ +#endif /* CPU_ARM */ + +#ifndef CLIP_SAMPLE_16_DEFINED +/* Generic implementation */ +static FORCE_INLINE int32_t clip_sample_16(int32_t sample) +{ + if ((int16_t)sample != sample) + sample = 0x7fff ^ (sample >> 31); + return sample; +} +#endif /* CLIP_SAMPLE_16_DEFINED */ + +#undef CLIP_SAMPLE_16_DEFINED + +#endif /* DSP_HELPER_H */ |