ISP: global variables definition cause the application to jump back to boot loader

I am trying to modify the example <apnt_180_test> from keil to exercise the ISP function.
post a link to the code you modify and tell us why you modify it.
ALSO which derivative?

When i add my golbal variables definition in boot loader, the application asm code will add one statment to jump to ?C_START,
NO assembler or compioler will add CODE (jump to ?C_START) because you add VARIABLES (add my golbal variables)
post your code

Erik

Hi, Erik,

because i would like the app1.c to access to the global variables defined in boot.c, i add two variables: a1 and a2 to test if my intention can work.

result:
It can't work if i given a1 and a2 the initial values, the control flow won't be able to jump to the routine: app_main.

the source comes from the keil example code "multi-application programming", see application note 180.

======boot.c==============================

extern void app_main (void);
extern int app_func1 (int i1, int i2);

int ar[4];

int a1 = 1;
int a2 = 2;

void boot_func1 (void)  {
  int f1_a [5];

  f1_a[0] = 0;
}

void boot_func2 (void)  {
  int f2_a [5];

  f2_a[0] = 0;
}

void main (void)  {

   boot_func1 ();
   app_main  ();     // call main appliation function (initialize)
   boot_func2 ();
   ar[1] = app_func1 (3, 4);
   while (1)  {
     ;
   }
}

========app1.c=================

extern void boot_func1 (void);   // function in Boot_Loader called from Application
extern void boot_func2 (void);   // function in Boot_Loader called from Application


extern int a1;
extern int a2;


char c1, c2;
char *p1 = &c1;
char *p2 = &c2;


void main (void)  {
  p1 = &c1;
  p2 = &c2;
  *p1 = *p2;
  boot_func2 ();
  boot_func1 ();

}


int app_func1 (int i1, int i2)  {
  return (i1 + i2);
}

======== build message of application part======
Build target 'Application'
compiling app1.c...
assembling STARTUP_Lite.A51...
assembling App1Call.Asm...

linking...
*** WARNING L16: UNCALLED FUNCTION, IGNORED FOR OVERLAY PROCESS NAME: MAIN/APP1
*** WARNING L16: UNCALLED FUNCTION, IGNORED FOR OVERLAY PROCESS NAME: ?C_INITSEG

Program Size: data=16.0 xdata=0 const=0 code=65
".\Object_App1\..\app1" - 0 Error(s), 2 Warning(s).

========= toolchain info======

IDE-Version:
猩ision3 V3.51
Copyright (c) Keil Elektronik GmbH / Keil Software, Inc. 1995 - 2007

Tool Version Numbers:
Toolchain Path: C:\Keil\C51\BIN\
C Compiler: C51.Exe V8.08
Assembler: A51.Exe V8.00d
Linker/Locator: LX51.Exe V4.10a
Librarian: LIBX51.Exe V4.24
Hex Converter: OHX51.Exe V1.36b
CPU DLL: S8051.DLL V3.11
Dialog DLL: DP51.DLL V2.49
Target DLL: BIN\MON51.DLL V2.41
Dialog DLL: TP51.DLL V2.49

try writing a small assembler module with the 2 variables you want and link it with both boot and app. You have total control in assembler, not in C

Erik