Imported msp430-libc-20100207

[msp430-libc.git] / src / stdlib / _reset_vector__.S

diff --git a/src/stdlib/_reset_vector__.S b/src/stdlib/_reset_vector__.S
new file mode 100644 (file)
index 0000000..2da9223
--- /dev/null
+++ b/src/stdlib/_reset_vector__.S
@@ -0,0 +1,40 @@
+/*****************************************************************
+ * Program starts here.
+ *   overwriting this label in the user program
+ *   causes removing all startup code except __do_global_ctors
+ *****************************************************************/
+        .section .init0, "ax", @progbits
+        .weak   _reset_vector__
+        .func   _reset_vector__
+
+        .p2align 1,0
+_reset_vector__:
+
+;    stack can be initialized in main() prologue,
+;    but setting stack pointer here allows to call subroutines 
+;    from startup code and call constructors of statically allocated C++ objects.
+;    Stack pointer will have the same value entering main() as here,
+;    so -mno-stack-init can be used to reduce code size.
+;    initial stack value can be set in ld script as __stack symbol 
+;    (end of RAM by default), or via -defsym __stack=<address> ld option
+;    or via -Wl,defsym,__stack=<address> gcc option, or by redefining
+;    __init_stack function as fololws:
+;
+;#if defined (__cplusplus)
+;extern "C" 
+;#endif
+;__attribute__((__naked__)) __attribute__((section(".init2"))) void __init_stack()
+;{
+;    asm volatile("\tmov\t#stack_addr, r1\n");
+;}
+;
+        /* request following functions to be linked if library _reset_vector__ used */
+
+        .global        __init_stack
+
+        .global        __low_level_init
+        .global        __do_copy_data
+        .global        __do_clear_bss
+        .global        __jump_to_main
+
+        .endfunc