Merge pull request #5 from mysterywolf/presupport

pre-support rt-thread software package

SConscript

@@ -0,0 +1,18 @@
+Import('rtconfig')
+from building import *
+
+src = ['perf_counter.c', 'os/rt-thread/perf_os_patch_rt_thread.c']
+
+if rtconfig.PLATFORM in ['armcc', 'armclang']: # Keil-MDK
+    src += ['systick_wrapper_ual.s']
+
+if rtconfig.PLATFORM == 'gcc':
+    src += ['systick_wrapper_gcc.s']
+
+cwd = GetCurrentDir()
+path = [cwd]
+group = []
+
+group = DefineGroup('perf_counter', src, depend = ['PKG_USING_PERFCOUNTER'], CPPPATH = path)
+
+Return('group')

systick_wrapper_gcc.s

@@ -28,10 +28,10 @@
 
 __wrap_SysTick_Handler:
     push    {r4, r5}
-    push        {r4, lr}
+    push    {r4, lr}
     ldr     R0, =user_code_insert_to_systick_handler
     blx     R0
-    pop         {r4, r5}
+    pop     {r4, r5}
     mov     lr, r5
     pop     {r4, r5}
     ldr     R0, =__real_SysTick_Handler