Move pcm_mixer helper routines to firmware/asm.

7 files changed, 755 insertions, 0 deletions

diff --git a/firmware/asm/arm/pcm-mixer-armv4.c b/firmware/asm/arm/pcm-mixer-armv4.c
new file mode 100644
index 0000000000..4818544d7b
--- /dev/null
+++ b/firmware/asm/arm/pcm-mixer-armv4.c
@@ -0,0 +1,182 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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.
+ *
+ ****************************************************************************/
+
+#define MIXER_OPTIMIZED_WRITE_SAMPLES
+#define MIXER_OPTIMIZED_MIX_SAMPLES
+
+/* Mix channels' samples and apply gain factors */
+static FORCE_INLINE void mix_samples(void *out,
+                                     void *src0,
+                                     int32_t src0_amp,
+                                     void *src1,
+                                     int32_t src1_amp,
+                                     size_t size)
+{
+    if (src0_amp == MIX_AMP_UNITY && src1_amp == MIX_AMP_UNITY)
+    {
+        /* Both are unity amplitude */
+        int32_t l0, l1, h0, h1;
+        asm volatile (
+        "1:                             \n"
+            "ldrsh  %4, [%1], #2        \n"
+            "ldrsh  %5, [%2], #2        \n"
+            "ldrsh  %6, [%1], #2        \n"
+            "ldrsh  %7, [%2], #2        \n"
+            "add    %4, %4, %5          \n"
+            "add    %6, %6, %7          \n"
+            "mov    %5, %4, asr #15     \n"
+            "teq    %5, %5, asr #31     \n"
+            "eorne  %4, %8, %4, asr #31 \n"
+            "mov    %7, %6, asr #15     \n"
+            "teq    %7, %7, asr #31     \n"
+            "eorne  %6, %8, %6, asr #31 \n"
+            "subs   %3, %3, #4          \n"
+            "and    %4, %4, %8, lsr #16 \n"
+            "orr    %6, %4, %6, lsl #16 \n"
+            "str    %6, [%0], #4        \n"
+            "bhi    1b                  \n"
+            : "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
+              "=&r"(l0), "=&r"(l1), "=&r"(h0), "=&r"(h1)
+            : "r"(0xffff7fff));
+    }
+    else if (src0_amp != MIX_AMP_UNITY && src1_amp != MIX_AMP_UNITY)
+    {
+        /* Neither are unity amplitude */
+        int32_t l0, l1, h0, h1;
+        asm volatile (
+        "1:                              \n"
+            "ldrsh  %4, [%1], #2         \n"
+            "ldrsh  %5, [%2], #2         \n"
+            "ldrsh  %6, [%1], #2         \n"
+            "ldrsh  %7, [%2], #2         \n"
+            "mul    %4, %8, %4           \n"
+            "mul    %5, %9, %5           \n"
+            "mul    %6, %8, %6           \n"
+            "mul    %7, %9, %7           \n"
+            "mov    %4, %4, asr #16      \n"
+            "add    %4, %4, %5, asr #16  \n"
+            "mov    %6, %6, asr #16      \n"
+            "add    %6, %6, %7, asr #16  \n"
+            "mov    %5, %4, asr #15      \n"
+            "teq    %5, %5, asr #31      \n"
+            "eorne  %4, %10, %4, asr #31 \n"
+            "mov    %7, %6, asr #15      \n"
+            "teq    %7, %7, asr #31      \n"
+            "eorne  %6, %10, %6, asr #31 \n"
+            "subs   %3, %3, #4           \n"
+            "and    %4, %4, %10, lsr #16 \n"
+            "orr    %6, %4, %6, lsl #16  \n"
+            "str    %6, [%0], #4         \n"
+            "bhi    1b                   \n"
+            : "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
+              "=&r"(l0), "=&r"(l1), "=&r"(h0), "=&r"(h1)
+            : "r"(src0_amp), "r"(src1_amp), "r"(0xffff7fff));
+    }
+    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;
+        }
+
+        int32_t l0, l1, h0, h1;
+        asm volatile (
+        "1:                             \n"
+            "ldrsh  %4, [%1], #2        \n"
+            "ldrsh  %5, [%2], #2        \n"
+            "ldrsh  %6, [%1], #2        \n"
+            "ldrsh  %7, [%2], #2        \n"
+            "mul    %5, %8, %5          \n"
+            "mul    %7, %8, %7          \n"
+            "add    %4, %4, %5, asr #16 \n"
+            "add    %6, %6, %7, asr #16 \n"
+            "mov    %5, %4, asr #15     \n"
+            "teq    %5, %5, asr #31     \n"
+            "eorne  %4, %9, %4, asr #31 \n"
+            "mov    %7, %6, asr #15     \n"
+            "teq    %7, %7, asr #31     \n"
+            "eorne  %6, %9, %6, asr #31 \n"
+            "subs   %3, %3, #4          \n"
+            "and    %4, %4, %9, lsr #16 \n"
+            "orr    %6, %4, %6, lsl #16 \n"
+            "str    %6, [%0], #4        \n"
+            "bhi    1b                  \n"
+            : "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
+              "=&r"(l0), "=&r"(l1), "=&r"(h0), "=&r"(h1)
+            : "r"(src1_amp), "r"(0xffff7fff));
+    }
+}
+
+/* Write channel's samples and apply gain factor */
+static FORCE_INLINE void write_samples(void *out,
+                                       void *src,
+                                       int32_t amp,
+                                       size_t size)
+{
+    if (LIKELY(amp == MIX_AMP_UNITY))
+    {
+        /* Channel is unity amplitude */
+        asm volatile (
+            "ands       r1, %2, #0x1f  \n"
+            "beq        2f             \n"
+        "1:                            \n"
+            "ldr        r0, [%1], #4   \n"
+            "subs       r1, r1, #4     \n"
+            "str        r0, [%0], #4   \n"
+            "bne        1b             \n"
+            "bics       %2, %2, #0x1f  \n"
+            "beq        3f             \n"
+        "2:                            \n"
+            "ldmia      %1!, { r0-r7 } \n"
+            "subs       %2, %2, #32    \n"
+            "stmia      %0!, { r0-r7 } \n"
+            "bhi        2b             \n"
+        "3:                            \n"
+            : "+r"(out), "+r"(src), "+r"(size)
+            :
+            : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7");
+    }
+    else
+    {
+        /* Channel needs amplitude cut */
+        uint32_t l, h;
+        asm volatile (
+        "1:                              \n"
+            "ldrsh   %3, [%1], #2        \n"
+            "ldrsh   %4, [%1], #2        \n"
+            "subs    %2, %2, #4          \n"
+            "mul     %3, %5, %3          \n"
+            "mul     %4, %5, %4          \n"
+            "and     %4, %4, %6, lsl #16 \n"
+            "orr     %4, %4, %3, lsr #16 \n"
+            "str     %4, [%0], #4        \n"
+            "bhi     1b                  \n"
+            : "+r"(out), "+r"(src), "+r"(size),
+              "=&r"(l), "=&r"(h)
+            : "r"(amp), "r"(0xffffffffu));
+    }     
+}
diff --git a/firmware/asm/arm/pcm-mixer-armv5.c b/firmware/asm/arm/pcm-mixer-armv5.c
new file mode 100644
index 0000000000..64f2c86f52
--- /dev/null
+++ b/firmware/asm/arm/pcm-mixer-armv5.c
@@ -0,0 +1,106 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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.
+ *
+ ****************************************************************************/
+
+#define MIXER_OPTIMIZED_WRITE_SAMPLES
+#define MIXER_OPTIMIZED_MIX_SAMPLES
+
+/* Mix channels' samples and apply gain factors */
+static FORCE_INLINE void mix_samples(void *out,
+                                     void *src0,
+                                     int32_t src0_amp,
+                                     void *src1,
+                                     int32_t src1_amp,
+                                     size_t size)
+{
+    int32_t s0, s1, tmp;
+    asm volatile (
+    "1:                             \n"
+        "ldr    %4, [%1], #4        \n"
+        "ldr    %5, [%2], #4        \n"
+        "smulwb %6, %7, %4          \n"
+        "smulwt %4, %7, %4          \n"
+        "smlawb %6, %8, %5, %6      \n"
+        "smlawt %4, %8, %5, %4      \n"
+        "mov    %5, %6, asr #15     \n"
+        "teq    %5, %5, asr #31     \n"
+        "eorne  %6, %9, %6, asr #31 \n"
+        "mov    %5, %4, asr #15     \n"
+        "teq    %5, %5, asr #31     \n"
+        "eorne  %4, %9, %4, asr #31 \n"
+        "subs   %3, %3, #4          \n"
+        "and    %6, %6, %9, lsr #16 \n"
+        "orr    %6, %6, %4, lsl #16 \n"
+        "str    %6, [%0], #4        \n"
+        "bhi    1b                  \n"
+        : "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
+          "=&r"(s0), "=&r"(s1), "=&r"(tmp)
+        : "r"(src0_amp), "r"(src1_amp), "r"(0xffff7fff));
+}
+
+/* Write channel's samples and apply gain factor */
+static FORCE_INLINE void write_samples(void *out,
+                                       void *src,
+                                       int32_t amp,
+                                       size_t size)
+{
+    if (LIKELY(amp == MIX_AMP_UNITY))
+    {
+        /* Channel is unity amplitude */
+        asm volatile (
+            "ands   r1, %2, #0x1f  \n"
+            "beq    2f             \n"
+        "1:                        \n"
+            "ldr    r0, [%1], #4   \n"
+            "subs   r1, r1, #4     \n"
+            "str    r0, [%0], #4   \n"
+            "bne    1b             \n"
+            "bics   %2, %2, #0x1f  \n"
+            "beq    3f             \n"
+        "2:                        \n"
+            "ldmia  %1!, { r0-r7 } \n"
+            "subs   %2, %2, #32    \n"
+            "stmia  %0!, { r0-r7 } \n"
+            "bhi    2b             \n"
+        "3:                        \n"
+            : "+r"(out), "+r"(src), "+r"(size)
+            :
+            : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7");
+    }
+    else
+    {
+        /* Channel needs amplitude cut */
+        uint32_t l, h;
+        asm volatile (
+        "1:                             \n"
+            "ldr    %3, [%1], #4        \n"
+            "subs   %2, %2, #4          \n"
+            "smulwt %4, %5, %3          \n"
+            "smulwb %3, %5, %3          \n"
+            "mov    %4, %4, lsl #16     \n"
+            "mov    %3, %3, lsl #16     \n"
+            "orr    %4, %4, %3, lsr #16 \n"
+            "str    %4, [%0], #4        \n"
+            "bhi    1b                  \n"
+            : "+r"(out), "+r"(src), "+r"(size),
+              "=&r"(l), "=&r"(h)
+            : "r"(amp));
+    }     
+}
diff --git a/firmware/asm/arm/pcm-mixer-armv6.c b/firmware/asm/arm/pcm-mixer-armv6.c
new file mode 100644
index 0000000000..94eecd0f90
--- /dev/null
+++ b/firmware/asm/arm/pcm-mixer-armv6.c
@@ -0,0 +1,118 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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.
+ *
+ ****************************************************************************/
+#define MIXER_OPTIMIZED_MIX_SAMPLES
+#define MIXER_OPTIMIZED_WRITE_SAMPLES
+
+/* Mix channels' samples and apply gain factors */
+static FORCE_INLINE void mix_samples(void *out,
+                                     void *src0,
+                                     int32_t src0_amp,
+                                     void *src1,
+                                     int32_t src1_amp,
+                                     size_t size)
+{
+    uint32_t s0, s1;
+
+    if (src0_amp == MIX_AMP_UNITY && src1_amp == MIX_AMP_UNITY)
+    {
+        /* Both are unity amplitude */
+        asm volatile (
+        "1:                      \n"
+            "ldr    %4, [%1], #4 \n"
+            "ldr    %5, [%2], #4 \n"
+            "subs   %3, %3, #4   \n"
+            "qadd16 %5, %5, %4   \n"
+            "str    %5, [%0], #4 \n"
+            "bhi    1b           \n"
+            : "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
+              "=&r"(s0), "=&r"(s1));
+    }
+    else
+    {
+        /* One or neither are unity amplitude */
+        uint32_t tmp;
+        asm volatile (
+        "1:                             \n"
+            "ldr    %4, [%1], #4        \n"
+            "ldr    %5, [%2], #4        \n"
+            "subs   %3, %3, #4          \n"
+            "smulwb %6, %7, %4          \n"
+            "smulwt %4, %7, %4          \n"
+            "smlawb %6, %8, %5, %6      \n"
+            "smlawt %4, %8, %5, %4      \n"
+            "ssat   %6, #16, %6         \n"
+            "ssat   %4, #16, %4         \n"
+            "pkhbt  %6, %6, %4, asl #16 \n"
+            "str    %6, [%0], #4        \n"
+            "bhi    1b                  \n"
+            : "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
+              "=&r"(s0), "=&r"(s1), "=&r"(tmp)
+            : "r"(src0_amp), "r"(src1_amp));
+    }
+}
+
+/* Write channel's samples and apply gain factor */
+static FORCE_INLINE void write_samples(void *out,
+                                       void *src,
+                                       int32_t amp,
+                                       size_t size)
+{
+    if (LIKELY(amp == MIX_AMP_UNITY))
+    {
+        /* Channel is unity amplitude */
+        asm volatile (
+            "ands       r1, %2, #0x1f  \n"
+            "beq        2f             \n"
+        "1:                            \n"
+            "ldr        r0, [%1], #4   \n"
+            "subs       r1, r1, #4     \n"
+            "str        r0, [%0], #4   \n"
+            "bne        1b             \n"
+            "bics       %2, %2, #0x1f  \n"
+            "beq        3f             \n"
+        "2:                            \n"
+            "ldmia      %1!, { r0-r7 } \n"
+            "subs       %2, %2, #32    \n"
+            "stmia      %0!, { r0-r7 } \n"
+            "bhi        2b             \n"
+        "3:                            \n"
+            : "+r"(out), "+r"(src), "+r"(size)
+            :
+            : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7");
+    }
+    else
+    {
+        /* Channel needs amplitude cut */
+        uint32_t s, tmp;
+        asm volatile(
+        "1:                             \n"
+            "ldr    %3, [%1], #4        \n"
+            "subs   %2, %2, #4          \n"
+            "smulwt %4, %5, %3          \n"
+            "smulwb %3, %5, %3          \n"
+            "pkhbt  %4, %3, %4, asl #16 \n"
+            "str    %4, [%0], #4        \n"
+            "bhi    1b                  \n"
+            : "+r"(out), "+r"(src), "+r"(size),
+              "=&r"(s), "=&r"(tmp)
+            : "r"(amp));
+    }     
+}
diff --git a/firmware/asm/arm/pcm-mixer.c b/firmware/asm/arm/pcm-mixer.c
new file mode 100644
index 0000000000..16c9c3575d
--- /dev/null
+++ b/firmware/asm/arm/pcm-mixer.c
@@ -0,0 +1,7 @@
+#if ARM_ARCH >= 6
+  #include "pcm-mixer-armv6.c"
+#elif ARM_ARCH >= 5
+  #include "pcm-mixer-armv5.c"
+#elif ARM_ARCH >= 4
+  #include "pcm-mixer-armv4.c"
+#endif
diff --git a/firmware/asm/generic/pcm-mixer.c b/firmware/asm/generic/pcm-mixer.c
new file mode 100644
index 0000000000..93841be70d
--- /dev/null
+++ 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
diff --git a/firmware/asm/m68k/pcm-mixer.c b/firmware/asm/m68k/pcm-mixer.c
new file mode 100644
index 0000000000..d8318fffaf
--- /dev/null
+++ b/firmware/asm/m68k/pcm-mixer.c
@@ -0,0 +1,134 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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.
+ *
+ ****************************************************************************/
+
+#define MIXER_OPTIMIZED_MIX_SAMPLES
+#define MIXER_OPTIMIZED_WRITE_SAMPLES
+static struct emac_context
+{
+    unsigned long r[4];
+} emac_context IBSS_ATTR;
+
+/* Save emac context affected in ISR */
+static FORCE_INLINE void save_emac_context(void)
+{
+    asm volatile (
+        "move.l   %%macsr, %%d0             \n"
+        "move.l   %%accext01, %%d1          \n"
+        "movclr.l %%acc0, %%a0              \n"
+        "movclr.l %%acc1, %%a1              \n"
+        "movem.l  %%d0-%%d1/%%a0-%%a1, (%0) \n"
+        :
+        : "a"(&emac_context)
+        : "d0", "d1", "a0", "a1");
+}
+
+/* Restore emac context affected in ISR */
+static FORCE_INLINE void restore_emac_context(void)
+{
+    asm volatile (
+        "movem.l (%0), %%d0-%%d1/%%a0-%%a1  \n"
+        "move.l  %%a1, %%acc1               \n"
+        "move.l  %%a0, %%acc0               \n"
+        "move.l  %%d1, %%accext01           \n"
+        "move.l  %%d0, %%macsr              \n"
+        :
+        : "a"(&emac_context)
+        : "d0", "d1", "a0", "a1");
+}
+
+/* Mix channels' samples and apply gain factors */
+static FORCE_INLINE void mix_samples(void *out,
+                                     void *src0,
+                                     int32_t src0_amp,
+                                     void *src1,
+                                     int32_t src1_amp,
+                                     size_t size)
+{
+    uint32_t s0, s1, s2, s3;
+    save_emac_context();
+    coldfire_set_macsr(EMAC_ROUND | EMAC_SATURATE);
+
+    asm volatile (
+        "move.l     (%1)+, %5                 \n"
+    "1:                                       \n"
+        "movea.w    %5, %4                    \n"
+        "asr.l      %10, %5                   \n"
+        "mac.l      %4, %8,            %%acc0 \n"
+        "mac.l      %5, %8, (%2)+, %5, %%acc1 \n"
+        "movea.w    %5, %4                    \n"
+        "asr.l      %10, %5                   \n"
+        "mac.l      %4, %9,            %%acc0 \n"
+        "mac.l      %5, %9, (%1)+, %5, %%acc1 \n"
+        "movclr.l   %%acc0, %6                \n"
+        "movclr.l   %%acc1, %7                \n"
+        "swap.w     %6                        \n"
+        "move.w     %6, %7                    \n"
+        "move.l     %7, (%0)+                 \n"
+        "subq.l     #4, %3                    \n"
+        "bhi.b      1b                        \n"
+        : "+a"(out), "+a"(src0), "+a"(src1), "+d"(size),
+          "=&a"(s0), "=&d"(s1), "=&d"(s2), "=&d"(s3)
+        : "r"(src0_amp), "r"(src1_amp), "d"(16)
+    );
+
+    restore_emac_context();
+}
+
+/* Write channel's samples and apply gain factor */
+static FORCE_INLINE void write_samples(void *out,
+                                       void *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 */
+        uint32_t s0, s1, s2, s3;
+        save_emac_context();
+        coldfire_set_macsr(EMAC_ROUND | EMAC_SATURATE);
+
+        asm volatile (
+            "move.l     (%1)+, %4                 \n"
+        "1:                                       \n"
+            "movea.w    %4, %3                    \n"
+            "asr.l      %8, %4                    \n"
+            "mac.l      %3, %7,            %%acc0 \n"
+            "mac.l      %4, %7, (%1)+, %4, %%acc1 \n"
+            "movclr.l   %%acc0, %5                \n"
+            "movclr.l   %%acc1, %6                \n"
+            "swap.w     %5                        \n"
+            "move.w     %5, %6                    \n"
+            "move.l     %6, (%0)+                 \n"
+            "subq.l     #4, %2                    \n"
+            "bhi.b      1b                        \n"
+            : "+a"(out), "+a"(src), "+d"(size),
+              "=&a"(s0), "=&d"(s1), "=&d"(s2), "=&d"(s3)
+            : "r"(amp), "d"(16)
+        );
+
+        restore_emac_context();
+    }     
+}
diff --git a/firmware/asm/pcm-mixer.c b/firmware/asm/pcm-mixer.c
new file mode 100644
index 0000000000..369e830427
--- /dev/null
+++ b/firmware/asm/pcm-mixer.c
@@ -0,0 +1,108 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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.
+ *
+ ****************************************************************************/
+
+#if defined(CPU_ARM)
+  #include "arm/pcm-mixer.c"
+#elif defined(CPU_COLDFIRE)
+  #include "m68k/pcm-mixer.c"
+#else
+
+/* generic pcm-mixer.c */
+#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