From 17886828c8cb682092b8ba18db0723598c3a7b73 Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Tue, 31 May 2016 17:31:28 +0100
Subject: [PATCH] cc3200/gccollect: Use MP_STATE_THREAD(stack_top) to get top
 of stack.

---
 cc3200/mptask.c         |  7 +++++--
 cc3200/util/gccollect.c | 12 ++----------
 cc3200/util/gccollect.h |  1 -
 3 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/cc3200/mptask.c b/cc3200/mptask.c
index 80d76f90e9..eb673b08cf 100644
--- a/cc3200/mptask.c
+++ b/cc3200/mptask.c
@@ -28,6 +28,7 @@
 #include <stdint.h>
 
 #include "py/mpconfig.h"
+#include "py/stackctrl.h"
 #include "py/obj.h"
 #include "py/runtime.h"
 #include "py/gc.h"
@@ -104,9 +105,8 @@ static const char fresh_boot_py[] = "# boot.py -- run on boot-up\r\n"
  ******************************************************************************/
 
 void TASK_Micropython (void *pvParameters) {
-    // initialize the garbage collector with the top of our stack
+    // get the top of the stack to initialize the garbage collector
     uint32_t sp = gc_helper_get_sp();
-    gc_collect_init (sp);
 
     bool safeboot = false;
     mptask_pre_init();
@@ -122,6 +122,9 @@ soft_reset:
     mp_thread_init();
     #endif
 
+    // initialise the stack pointer for the main thread (must be done after mp_thread_init)
+    mp_stack_set_top((void*)sp);
+
     // GC init
     gc_init(&_boot, &_eheap);
 
diff --git a/cc3200/util/gccollect.c b/cc3200/util/gccollect.c
index bc9cba4b8d..8963852f7a 100644
--- a/cc3200/util/gccollect.c
+++ b/cc3200/util/gccollect.c
@@ -29,23 +29,15 @@
 #include <stdint.h>
 
 #include "py/mpconfig.h"
+#include "py/mpstate.h"
 #include "py/gc.h"
 #include "py/mpthread.h"
 #include "gccollect.h"
 #include "gchelper.h"
 
-/******************************************************************************
-DECLARE PRIVATE DATA
- ******************************************************************************/
-static uint32_t stackend;
-
-
 /******************************************************************************
 DECLARE PUBLIC FUNCTIONS
  ******************************************************************************/
-void gc_collect_init (uint32_t sp) {
-    stackend = sp;
-}
 
 void gc_collect(void) {
     // start the GC
@@ -56,7 +48,7 @@ void gc_collect(void) {
     mp_uint_t sp = gc_helper_get_regs_and_sp(regs);
 
     // trace the stack, including the registers (since they live on the stack in this function)
-    gc_collect_root((void**)sp, (stackend - sp) / sizeof(uint32_t));
+    gc_collect_root((void**)sp, ((mp_uint_t)MP_STATE_THREAD(stack_top) - sp) / sizeof(uint32_t));
 
     // trace root pointers from any threads
     #if MICROPY_PY_THREAD
diff --git a/cc3200/util/gccollect.h b/cc3200/util/gccollect.h
index 24cd60288e..281e84aa83 100644
--- a/cc3200/util/gccollect.h
+++ b/cc3200/util/gccollect.h
@@ -38,5 +38,4 @@ extern uint32_t _eheap;
 extern uint32_t _stack;
 extern uint32_t _estack;
 
-void gc_collect_init (uint32_t sp);
 void gc_collect(void);