Add codecs to librbcodec.

Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97
Reviewed-on: http://gerrit.rockbox.org/137
Reviewed-by: Nils Wallménius <nils@rockbox.org>
Tested-by: Nils Wallménius <nils@rockbox.org>

lib/rbcodec/codecs/codec_crt0.c

@@ -0,0 +1,74 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 Tomasz Malesinski
+ *
+ * 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 "codecs.h"
+
+struct codec_api *ci DATA_ATTR;
+
+extern unsigned char plugin_bss_start[];
+extern unsigned char plugin_end_addr[];
+
+/* stub, the entry point is called via its reference in __header to
+ * avoid warning with certain compilers */
+int _start(void) {return 0;}
+
+enum codec_status codec_start(enum codec_entry_call_reason reason)
+{
+#if (CONFIG_PLATFORM & PLATFORM_NATIVE)
+    if (reason == CODEC_LOAD)
+    {
+#ifdef USE_IRAM
+        extern char iramcopy[], iramstart[], iramend[], iedata[], iend[];
+        size_t iram_size = iramend - iramstart;
+        size_t ibss_size = iend - iedata;
+        if (iram_size > 0 || ibss_size > 0)
+        {
+            ci->memcpy(iramstart, iramcopy, iram_size);
+            ci->memset(iedata, 0, ibss_size);
+            /* make the icache (if it exists) up to date with the new code */
+            ci->commit_discard_idcache();
+            /* barrier to prevent reordering iram copy and BSS clearing,
+             * because the BSS segment alias the IRAM copy.
+             */
+            asm volatile ("" ::: "memory");
+        }
+#endif /* PLUGIN_USE_IRAM */
+        ci->memset(plugin_bss_start, 0, plugin_end_addr - plugin_bss_start);
+        /* Some parts of bss may be used via a no-cache alias (at least
+         * portalplayer has this). If we don't clear the cache, those aliases
+         * may read garbage */
+        ci->commit_dcache();
+    }
+#endif /* CONFIG_PLATFORM */
+
+    /* Note: If for any reason codec_main would not be called with CODEC_LOAD
+     * because the above code failed then it must not be ever be called with
+     * any other value and some strategy to avoid doing so must be conceived */
+    return codec_main(reason);
+}
+
+#if defined(CPU_ARM) && (CONFIG_PLATFORM & PLATFORM_NATIVE)
+void __attribute__((naked)) __div0(void)
+{
+    asm volatile("bx %0" : : "r"(ci->__div0));
+}
+#endif