arm - Reason for tampering of bitband maping address at run time -

i using bit banding set , clear gpio6[1] of lpc1857 using keil.

the mapping address in bit band region set gpio6[1] comes 0x43ec4304

the mapping address in bit band region clear gpio6[1] comes 0x43ec5384

the gpio gets set not cleared.

when checked on debugger, observed mapping address clear gpio6[1] getting set 0x43ec5000. gpio not clear.

can please understand why happening ? , how can resolve mapping address setting wrong address @ run time ?

following code snippet:

/*in "main.c"*/  int main() {     ... //system initialization     ... //gpio init     ...       toggle_peri(); }   /*in "peri.c"*/   /* bit band peripheral definitions */  #define bitband_peri_ref     0x40000000 //start address of peripherals #define bitband_peri_base    0x42000000 //start address of peripheral bit band alias region  /* basic bit band function definition */ #define bitband_peri(a,b) ((bitband_peri_base + ((a-bitband_peri_ref)*(0x20)) + (b*(0x04))))  // convert gpio address  #define bitband_peri_setclearbit(a,b)   ((*(volatile uint32_t *) (bitband_peri(a,b))) = 1)  /*note: base address of gpio       =  0x400f 4000*/ #define peri_gpio_address_s 0x400f6218 //for gpio6[1] set #define peri_gpio_address_c 0x400f629c //for gpio6[1] clear #define peri_gpio_bit       1   ... ... ... ...  void toggle_peri(void) {     bitband_peri_setclearbit(peri_gpio_address_s,peri_gpio_bit);    //set pin     delay(0xffff);       bitband_peri_setclearbit(peri_gpio_address_c,peri_gpio_bit);    //clear pin     delay(0xffff); } 

thanks.