Add CPU-model-specific init to newborn threads. Add default %macsr for each thread created on coldfire (EMAC_FRACTIONAL | EMAC_SATURATE).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12483 a1c6a512-1295-4272-9138-f99709370657

firmware/target/coldfire/system-coldfire.c

@@ -234,16 +234,13 @@ void (* const vbr[]) (void) __attribute__ ((section (".vectors"))) =
 void system_init(void)
 {
     /* Clear the accumulators. From here on it's the responsibility of
-       whoever uses them to clear them after use (use movclr instruction). */
+       whoever uses them to clear them after use and before giving control
+       to "foreign" code (use movclr instruction). */
     asm volatile ("movclr.l %%acc0, %%d0\n\t"
                   "movclr.l %%acc1, %%d0\n\t"
                   "movclr.l %%acc2, %%d0\n\t"
                   "movclr.l %%acc3, %%d0\n\t"
                   : : : "d0");
-    /* Set EMAC unit to fractional mode with saturation, since that's
-       what'll be the most useful for most things which the main thread
-       will do. */
-    coldfire_set_macsr(EMAC_FRACTIONAL | EMAC_SATURATE);
 
     /* Set INTBASE and SPURVEC */
     INTBASE = 64;

firmware/thread.c

@@ -141,6 +141,13 @@ static inline void load_context(const void* addr)
     );
 }
 
+/* Set EMAC unit to fractional mode with saturation for each new thread,
+   since that's what'll be the most useful for most things which the dsp
+   will do. Codecs should still initialize their preferred modes
+   explicitly. */
+#define THREAD_CPU_INIT(core, thread) \
+    ({ (thread)->context.macsr = EMAC_FRACTIONAL | EMAC_SATURATE; })
+
 #elif CONFIG_CPU == SH7034
 /*---------------------------------------------------------------------------
  * Store non-volatile context.
@@ -193,6 +200,11 @@ static inline void load_context(const void* addr)
 
 #endif
 
+#ifndef THREAD_CPU_INIT
+/* No cpu specific init - make empty */
+#define THREAD_CPU_INIT(core, thread)
+#endif
+
 static void add_to_list(struct thread_entry **list, struct thread_entry *thread)
 {
     if (*list == NULL)
@@ -660,6 +672,10 @@ struct thread_entry*
     regs->sp = (void*)(((unsigned int)stack + stack_size) & ~3);
     regs->start = (void*)function;
 
+    /* Do any CPU specific inits after initializing common items
+       to have access to valid data */
+    THREAD_CPU_INIT(core, thread);
+
     return thread;
 }
 
@@ -753,10 +769,12 @@ void init_threads(void)
      * probably a much better way to do this. */
     if (core == CPU)
     {
+        THREAD_CPU_INIT(core, &cores[CPU].threads[0]);
         cores[CPU].threads[0].stack = stackbegin;
         cores[CPU].threads[0].stack_size = (int)stackend - (int)stackbegin;
     } else {
 #if NUM_CORES > 1  /* This code path will not be run on single core targets */
+        THREAD_CPU_INIT(core, &cores[COP].threads[0]);
         cores[COP].threads[0].stack = cop_stackbegin;
         cores[COP].threads[0].stack_size =
             (int)cop_stackend - (int)cop_stackbegin;