change main.c for relocatable reGNUal

src/main.c

@@ -1,7 +1,7 @@
 /*
  * main.c - main routine of Gnuk
  *
- * Copyright (C) 2010, 2011, 2012 Free Software Initiative of Japan
+ * Copyright (C) 2010, 2011, 2012, 2013 Free Software Initiative of Japan
  * Author: NIIBE Yutaka <gniibe@fsij.org>
  *
  * This file is a part of Gnuk, a GnuPG USB Token implementation.
@@ -321,6 +321,23 @@ led_blink (int spec)
   chEvtSignalFlags (main_thread, spec);
 }
 
+/*
+ * In Gnuk 1.0.[12], reGNUal was not relocatable.
+ * Now, it's relocatable, but we need to calculate its entry address
+ * based on it's pre-defined address.
+ */
+#define REGNUAL_START_ADDRESS_COMPATIBLE 0x20001400
+static uint32_t
+calculate_regnual_entry_address (const uint8_t *addr)
+{
+  const uint8_t *p = addr + 4;
+  uint32_t v = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24);
+
+  v -= REGNUAL_START_ADDRESS_COMPATIBLE;
+  v += (uint32_t)addr;
+  return v;
+}
+
 
 /*
  * Entry point.
@@ -332,6 +349,7 @@ int
 main (int argc, char *argv[])
 {
   unsigned int count = 0;
+  uint32_t entry;
 
   (void)argc;
   (void)argv;
@@ -438,6 +456,7 @@ main (int argc, char *argv[])
   port_disable ();
   /* Set vector */
   SCB->VTOR = (uint32_t)&_regnual_start;
+  entry = calculate_regnual_entry_address (&_regnual_start);
 #ifdef DFU_SUPPORT
 #define FLASH_SYS_START_ADDR 0x08000000
 #define FLASH_SYS_END_ADDR (0x08000000+0x1000)
@@ -456,12 +475,12 @@ main (int argc, char *argv[])
     flash_write (FLASH_SYS_START_ADDR, &_sys, 0x1000);
 
     /* Leave Gnuk to exec reGNUal */
-    (*func) (*((void (**)(void))(&_regnual_start+4)));
+    (*func) ((void (*)(void))entry);
     for (;;);
   }
 #else
   /* Leave Gnuk to exec reGNUal */
-  flash_erase_all_and_exec (*((void (**)(void))(&_regnual_start+4)));
+  flash_erase_all_and_exec ((void (*)(void))entry);
 #endif
 
   /* Never reached */