1 files changed, 142 insertions, 0 deletions

diff --git a/apps/beep.c b/apps/beep.c
new file mode 100644
index 0000000000..716847263e
--- /dev/null
+++ b/apps/beep.c
@@ -0,0 +1,142 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (c) 2011 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 "config.h"
+#include "system.h"
+#include "settings.h"
+#include "dsp.h"
+#include "pcm.h"
+#include "pcm_mixer.h"
+#include "misc.h"
+
+static int32_t beep_phase;      /* Phase of square wave generator */
+static uint32_t beep_step;      /* Step of square wave generator on each sample */
+static uint32_t beep_amplitude; /* Amplitude of square wave generator */
+static int beep_count;          /* Number of samples remaining to generate */
+
+/* Reserve enough static space for keyclick to fit */
+#define BEEP_BUF_COUNT (NATIVE_FREQUENCY / 1000 * KEYCLICK_DURATION)
+static uint32_t beep_buf[BEEP_BUF_COUNT] IBSS_ATTR;
+
+/* Actually output samples into beep_buf */
+#if defined(CPU_ARM)
+static FORCE_INLINE void beep_generate(int count)
+{
+    uint32_t *out = beep_buf;
+    uint32_t s;
+
+    asm volatile (
+    "1:                            \n"
+        "eor   %3, %5, %1, asr #31 \n"
+        "subs  %2, %2, #1          \n"
+        "str   %3, [%0], #4        \n"
+        "add   %1, %1, %4          \n"
+        "bgt   1b                  \n"
+        : "+r"(out), "+r"(beep_phase), "+r"(count),
+          "=&r"(s)
+        : "r"(beep_step), "r"(beep_amplitude));
+}
+#elif defined (CPU_COLDFIRE)
+static FORCE_INLINE void beep_generate(int count)
+{
+    uint32_t *out = beep_buf;
+    uint32_t s;
+
+    asm volatile (
+    "1:                   \n"
+        "move.l %1, %3    \n"
+        "add.l  %4, %1    \n"
+        "add.l  %3, %3    \n"
+        "subx.l %3, %3    \n"
+        "eor.l  %5, %3    \n"
+        "move.l %3, (%0)+ \n"
+        "subq.l #1, %2    \n"
+        "bgt.b  1b        \n"
+        : "+a"(out), "+d"(beep_phase), "+d"(count),
+          "=&d"(s)
+        : "r"(beep_step), "d"(beep_amplitude));
+}
+#else
+static FORCE_INLINE void beep_generate(int count)
+{
+    uint32_t *out = beep_buf;
+    uint32_t amplitude = beep_amplitude;
+    uint32_t step = beep_step;
+    int32_t phase = beep_phase;
+
+    do
+    {
+        *out++ = (phase >> 31) ^ amplitude;
+        phase += step;
+    }
+    while (--count > 0);
+
+    beep_phase = phase;
+}
+#endif
+
+/* Callback to generate the beep frames - also don't want inlining of
+   call below in beep_play */
+static void __attribute__((noinline)) ICODE_ATTR
+beep_get_more(unsigned char **start, size_t *size)
+{
+    int count = beep_count;
+
+    if (count > 0)
+    {
+        count = MIN(count, BEEP_BUF_COUNT);
+        beep_count -= count;
+        *start = (unsigned char *)beep_buf;
+        *size = count * sizeof(uint32_t);
+        beep_generate(count);
+    }
+}
+
+/* Generates a constant square wave sound with a given frequency in Hertz for
+   a duration in milliseconds */
+void beep_play(unsigned int frequency, unsigned int duration,
+               unsigned int amplitude)
+{
+    mixer_channel_stop(PCM_MIXER_CHAN_BEEP);
+
+    if (frequency == 0 || duration == 0 || amplitude == 0)
+        return;
+
+    if (amplitude > INT16_MAX)
+        amplitude = INT16_MAX;
+
+    /* Setup the parameters for the square wave generator */
+    beep_phase = 0;
+    beep_step = 0xffffffffu / NATIVE_FREQUENCY * frequency;
+    beep_count = NATIVE_FREQUENCY / 1000 * duration;
+    beep_amplitude = amplitude | (amplitude << 16); /* Word:|AMP16|AMP16| */
+
+    /* If it fits - avoid cb overhead */
+    unsigned char *start;
+    size_t size;
+
+    /* Generate first frame here */
+    beep_get_more(&start, &size);
+
+    mixer_channel_set_amplitude(PCM_MIXER_CHAN_BEEP, MIX_AMP_UNITY);
+    mixer_channel_play_data(PCM_MIXER_CHAN_BEEP,
+                            beep_count ? beep_get_more : NULL,
+                            start, size);
+}