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-rw-r--r--firmware/asm/generic/pcm-mixer.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/firmware/asm/generic/pcm-mixer.c b/firmware/asm/generic/pcm-mixer.c
new file mode 100644
index 0000000000..93841be70d
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+++ b/firmware/asm/generic/pcm-mixer.c
@@ -0,0 +1,100 @@
+/***************************************************************************
+ * __________ __ ___.
+ * 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.
+ *
+ ****************************************************************************/
+
+#include "dsp-util.h" /* for clip_sample_16 */
+/* Mix channels' samples and apply gain factors */
+static FORCE_INLINE void mix_samples(uint32_t *out,
+ int16_t *src0,
+ int32_t src0_amp,
+ int16_t *src1,
+ int32_t src1_amp,
+ size_t size)
+{
+ if (src0_amp == MIX_AMP_UNITY && src1_amp == MIX_AMP_UNITY)
+ {
+ /* Both are unity amplitude */
+ do
+ {
+ int32_t l = *src0++ + *src1++;
+ int32_t h = *src0++ + *src1++;
+ *out++ = (uint16_t)clip_sample_16(l) | (clip_sample_16(h) << 16);
+ }
+ while ((size -= 4) > 0);
+ }
+ else if (src0_amp != MIX_AMP_UNITY && src1_amp != MIX_AMP_UNITY)
+ {
+ /* Neither are unity amplitude */
+ do
+ {
+ int32_t l = (*src0++ * src0_amp >> 16) + (*src1++ * src1_amp >> 16);
+ int32_t h = (*src0++ * src0_amp >> 16) + (*src1++ * src1_amp >> 16);
+ *out++ = (uint16_t)clip_sample_16(l) | (clip_sample_16(h) << 16);
+ }
+ while ((size -= 4) > 0);
+ }
+ else
+ {
+ /* One is unity amplitude */
+ if (src0_amp != MIX_AMP_UNITY)
+ {
+ /* Keep unity in src0, amp0 */
+ int16_t *src_tmp = src0;
+ src0 = src1;
+ src1 = src_tmp;
+ src1_amp = src0_amp;
+ src0_amp = MIX_AMP_UNITY;
+ }
+
+ do
+ {
+ int32_t l = *src0++ + (*src1++ * src1_amp >> 16);
+ int32_t h = *src0++ + (*src1++ * src1_amp >> 16);
+ *out++ = (uint16_t)clip_sample_16(l) | (clip_sample_16(h) << 16);
+ }
+ while ((size -= 4) > 0);
+ }
+}
+
+/* Write channel's samples and apply gain factor */
+static FORCE_INLINE void write_samples(uint32_t *out,
+ int16_t *src,
+ int32_t amp,
+ size_t size)
+{
+ if (LIKELY(amp == MIX_AMP_UNITY))
+ {
+ /* Channel is unity amplitude */
+ memcpy(out, src, size);
+ }
+ else
+ {
+ /* Channel needs amplitude cut */
+ do
+ {
+ int32_t l = *src++ * amp >> 16;
+ int32_t h = *src++ * amp & 0xffff0000;
+ *out++ = (uint16_t)l | h;
+ }
+ while ((size -= 4) > 0);
+ }
+}
+
+#endif