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94039790f8
As Peter Meerwald <p.meerwald@bct-electronic.com> discovered, our ARM svolume code performance is quite terrible when the incoming samples are not word-aligned. This can very easily be the case, since the architecture only requires that the samples be 16-bit aligned, and we might end up running the innermost loop after processing modulo-4 samples. The performance degradation was ~50x on a Cortex A9 (Pandaboard). This reworks the svolume logic to first consume enough samples to make sure the rest is word aligned, and reordering the processing to work with 4 samples at a time first, and then finally deal with the remainder. With this, performance is comparable for arbitrary alignments (~3x faster than the C code).
169 lines
5.7 KiB
C
169 lines
5.7 KiB
C
/***
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This file is part of PulseAudio.
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Copyright 2004-2006 Lennart Poettering
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Copyright 2009 Wim Taymans <wim.taymans@collabora.co.uk>
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PulseAudio is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 2.1 of the License,
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or (at your option) any later version.
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PulseAudio is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with PulseAudio; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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USA.
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***/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <pulsecore/random.h>
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#include <pulsecore/macro.h>
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#include <pulsecore/endianmacros.h>
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#include "cpu-arm.h"
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#include "sample-util.h"
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#if defined (__arm__) && defined (HAVE_ARMV6)
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#define MOD_INC() \
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" subs r0, r6, %2 \n\t" \
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" itt cs \n\t" \
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" addcs r0, %1 \n\t" \
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" movcs r6, r0 \n\t"
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static pa_do_volume_func_t _volume_ref;
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static void pa_volume_s16ne_arm(int16_t *samples, const int32_t *volumes, unsigned channels, unsigned length) {
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/* Channels must be at least 4, and always a multiple of the original number.
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* This is also the max amount we overread the volume array, which should
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* have enough padding. */
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const int32_t *ve = volumes + (channels == 3 ? 6 : PA_MAX (4U, channels));
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unsigned rem = PA_ALIGN((size_t) samples) - (size_t) samples;
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/* Make sure we're word-aligned, else performance _really_ sucks */
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if (rem) {
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_volume_ref(samples, volumes, channels, rem < length ? rem : length);
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if (rem < length) {
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length -= rem;
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samples += rem / sizeof(*samples);
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} else
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return; /* we're done */
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}
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__asm__ __volatile__ (
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" mov r6, %4 \n\t" /* r6 = volumes + rem */
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" mov %3, %3, LSR #1 \n\t" /* length /= sizeof (int16_t) */
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" cmp %3, #4 \n\t" /* check for 4+ samples */
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" blt 2f \n\t"
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/* See final case for how the multiplication works */
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"1: \n\t"
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" ldrd r2, [r6], #8 \n\t" /* 4 samples at a time */
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" ldrd r4, [r6], #8 \n\t"
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" ldrd r0, [%0] \n\t"
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#ifdef WORDS_BIGENDIAN
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" smulwt r2, r2, r0 \n\t"
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" smulwb r3, r3, r0 \n\t"
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" smulwt r4, r4, r1 \n\t"
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" smulwb r5, r5, r1 \n\t"
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#else
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" smulwb r2, r2, r0 \n\t"
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" smulwt r3, r3, r0 \n\t"
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" smulwb r4, r4, r1 \n\t"
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" smulwt r5, r5, r1 \n\t"
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#endif
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" ssat r2, #16, r2 \n\t"
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" ssat r3, #16, r3 \n\t"
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" ssat r4, #16, r4 \n\t"
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" ssat r5, #16, r5 \n\t"
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#ifdef WORDS_BIGENDIAN
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" pkhbt r0, r3, r2, LSL #16 \n\t"
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" pkhbt r1, r5, r4, LSL #16 \n\t"
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#else
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" pkhbt r0, r2, r3, LSL #16 \n\t"
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" pkhbt r1, r4, r5, LSL #16 \n\t"
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#endif
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" strd r0, [%0], #8 \n\t"
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MOD_INC()
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" subs %3, %3, #4 \n\t"
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" cmp %3, #4 \n\t"
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" bge 1b \n\t"
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"2: \n\t"
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" cmp %3, #2 \n\t"
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" blt 3f \n\t"
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" ldrd r2, [r6], #8 \n\t" /* 2 samples at a time */
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" ldr r0, [%0] \n\t"
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#ifdef WORDS_BIGENDIAN
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" smulwt r2, r2, r0 \n\t"
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" smulwb r3, r3, r0 \n\t"
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#else
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" smulwb r2, r2, r0 \n\t"
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" smulwt r3, r3, r0 \n\t"
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#endif
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" ssat r2, #16, r2 \n\t"
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" ssat r3, #16, r3 \n\t"
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#ifdef WORDS_BIGENDIAN
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" pkhbt r0, r3, r2, LSL #16 \n\t"
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#else
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" pkhbt r0, r2, r3, LSL #16 \n\t"
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#endif
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" str r0, [%0], #4 \n\t"
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MOD_INC()
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" subs %3, %3, #2 \n\t"
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"3: \n\t" /* check for odd # of samples */
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" cmp %3, #1 \n\t"
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" bne 4f \n\t"
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" ldr r0, [r6], #4 \n\t" /* r0 = volume */
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" ldrh r2, [%0] \n\t" /* r2 = sample */
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" smulwb r0, r0, r2 \n\t" /* r0 = (r0 * r2) >> 16 */
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" ssat r0, #16, r0 \n\t" /* r0 = PA_CLAMP(r0, 0x7FFF) */
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" strh r0, [%0], #2 \n\t" /* sample = r0 */
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"4: \n\t"
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: "+r" (samples), "+r" (volumes), "+r" (ve), "+r" (length)
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: "r" (volumes + ((rem / sizeof(*samples)) % channels))
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: "r6", "r5", "r4", "r3", "r2", "r1", "r0", "cc"
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);
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}
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#endif /* defined (__arm__) && defined (HAVE_ARMV6) */
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void pa_volume_func_init_arm(pa_cpu_arm_flag_t flags) {
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#if defined (__arm__) && defined (HAVE_ARMV6)
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pa_log_info("Initialising ARM optimized volume functions.");
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if (!_volume_ref)
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_volume_ref = pa_get_volume_func(PA_SAMPLE_S16NE);
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pa_set_volume_func(PA_SAMPLE_S16NE, (pa_do_volume_func_t) pa_volume_s16ne_arm);
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#endif /* defined (__arm__) && defined (HAVE_ARMV6) */
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}
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