Implement Linker Script and Startup File

1 files changed, 50 insertions, 0 deletions

diff --git a/src/startup.c b/src/startup.c
new file mode 100644
index 0000000..b71a805
--- /dev/null
+++ b/src/startup.c
@@ -0,0 +1,50 @@
+
+
+#define STACK_TOP 0x20005000
+
+
+extern unsigned int _BSS_START;
+extern unsigned int _BSS_END;
+extern unsigned int _DATA_ROM_START;
+extern unsigned int _DATA_RAM_START;
+extern unsigned int _DATA_RAM_END;
+
+void startup();
+void main();
+
+// Define the vector table
+unsigned int * myvectors[2] 
+__attribute__ ((section("vectors")))= {
+    (unsigned int *)    STACK_TOP,  // stack pointer
+    (unsigned int *)    startup     // code entry point
+};
+
+void startup()
+{
+    /* Set memory in bss segment to zeros */
+    unsigned int * bss_start_p = &_BSS_START; 
+    unsigned int * bss_end_p = &_BSS_END;
+
+    while(bss_start_p != bss_end_p)
+    {
+        *bss_start_p = 0;
+        bss_start_p++;
+    }
+
+    /* Copy memory in data segment from its position
+     * in the flash image to its position in the
+     * read/write memory */
+    unsigned int * data_rom_start_p = &_DATA_ROM_START;
+    unsigned int * data_ram_start_p = &_DATA_RAM_START;
+    unsigned int * data_ram_end_p = &_DATA_RAM_END;
+
+    while(data_ram_start_p != data_ram_end_p)
+    {
+        *data_ram_start_p = *data_rom_start_p;
+        data_ram_start_p++;
+        data_rom_start_p++;
+    }
+
+    /* Now we are ready to start the main function */
+    main();
+}