Create fimrware/asm directory for assembly optimized stuff.

This dir is suitable for stuff that doesn't fit the target tree, e.g. because
it also builds on hosted or otherwise. It also has a generic subfolder for
fallback C implementations so that not all archs need to provide asm files.

SOURCES should only contain "foo.c" where foo.c includes the specific
<arch>/foo.c files from the subdirs using the preprocessor. This way automatic
selection of asm versions or generic C verion is possible.

For the start, the thread support files are moved, since ASM threads can
be used on hosted platforms as well. Since core_sleep() remains platform
specific it's moved to the corresponding system.h headers.

Change-Id: Iebff272f3407a6eaafeb7656ceb0ae9eca3f7cb9

2 files changed, 130 insertions, 0 deletions

diff --git a/firmware/asm/arm/thread.c b/firmware/asm/arm/thread.c
new file mode 100644
index 0000000000..fd443f2873
--- /dev/null
+++ b/firmware/asm/arm/thread.c
@@ -0,0 +1,94 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 by Thom Johansen
+ *
+ * Generic ARM threading support
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/*---------------------------------------------------------------------------
+ * Start the thread running and terminate it if it returns
+ *---------------------------------------------------------------------------
+ */
+static void __attribute__((naked)) USED_ATTR start_thread(void)
+{
+    /* r0 = context */
+    asm volatile (
+        "ldr    sp, [r0, #32]            \n" /* Load initial sp */
+        "ldr    r4, [r0, #40]            \n" /* start in r4 since it's non-volatile */
+        "mov    r1, #0                   \n" /* Mark thread as running */
+        "str    r1, [r0, #40]            \n"
+#if NUM_CORES > 1
+        "ldr    r0, =commit_discard_idcache \n" /* Invalidate this core's cache. */
+        "mov    lr, pc                   \n" /* This could be the first entry into */
+        "bx     r0                       \n" /* plugin or codec code for this core. */
+#endif
+        "mov    lr, pc                   \n" /* Call thread function */
+        "bx     r4                       \n"
+    ); /* No clobber list - new thread doesn't care */
+    thread_exit();
+#if 0
+    asm volatile (".ltorg"); /* Dump constant pool */
+#endif
+}
+
+/* For startup, place context pointer in r4 slot, start_thread pointer in r5
+ * slot, and thread function pointer in context.start. See load_context for
+ * what happens when thread is initially going to run. */
+#define THREAD_STARTUP_INIT(core, thread, function) \
+    ({ (thread)->context.r[0] = (uint32_t)&(thread)->context,  \
+       (thread)->context.r[1] = (uint32_t)start_thread, \
+       (thread)->context.start = (uint32_t)function; })
+
+
+/*---------------------------------------------------------------------------
+ * Store non-volatile context.
+ *---------------------------------------------------------------------------
+ */
+static inline void store_context(void* addr)
+{
+    asm volatile(
+        "stmia  %0, { r4-r11, sp, lr } \n"
+        : : "r" (addr)
+    );
+}
+
+/*---------------------------------------------------------------------------
+ * Load non-volatile context.
+ *---------------------------------------------------------------------------
+ */
+static inline void load_context(const void* addr)
+{
+    asm volatile(
+        "ldr     r0, [%0, #40]          \n" /* Load start pointer */
+        "cmp     r0, #0                 \n" /* Check for NULL */
+
+        /* If not already running, jump to start */
+#if ARM_ARCH == 4 && defined(USE_THUMB)
+        "ldmneia %0, { r0, r12 }        \n"
+        "bxne    r12                    \n"
+#else
+        "ldmneia %0, { r0, pc }         \n"
+#endif
+
+        "ldmia   %0, { r4-r11, sp, lr } \n" /* Load regs r4 to r14 from context */
+        : : "r" (addr) : "r0" /* only! */
+    );
+}
+
+
diff --git a/firmware/asm/arm/thread.h b/firmware/asm/arm/thread.h
new file mode 100644
index 0000000000..ec9bbcb3cd
--- /dev/null
+++ b/firmware/asm/arm/thread.h
@@ -0,0 +1,36 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2002 by Ulf Ralberg
+ *
+ * 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"
+
+struct regs
+{
+    uint32_t r[8];  /*  0-28 - Registers r4-r11 */
+    uint32_t sp;    /*    32 - Stack pointer (r13) */
+    uint32_t lr;    /*    36 - r14 (lr) */
+    uint32_t start; /*    40 - Thread start address, or NULL when started */
+};
+
+#if (CONFIG_PLATFORM & PLATFORM_HOSTED)
+  #define DEFAULT_STACK_SIZE 0x1000 /* Bytes */
+#else
+  #define DEFAULT_STACK_SIZE 0x400  /* Bytes */
+#endif