Doubt regarding the volatile keyword

[Goran_]

(1)volatile unsigned char * ADC_address;
--------ADC_address is a pointer which stores a volatile unsigned character .

(2)volatile unsigned int ADC_voltage = 0;
--------ADC_voltage is volatile unsigned integer variable ,

(3)volatile unsigned char * ADC_REAL_ADDRESS;
ADC_REAL_ADDRESS = (volatile unsigned char *)STA_MEMORY_BASE;
---------Typecasting STA_MEMORY_BASE to volatile unsigned char pointer and assigned to ADC_REAL_ADDRESS.

If I wrong means please correct me.

(4)Can anyone explain the below statements
#define PINSEL_BASE_ADDR 0xE002C000
#define PINSEL0 (*(volatile unsigned long *)(PINSEL_BASE_ADDR + 0x00))

what I understood is (volatile unsigned long *)(PINSEL_BASE_ADDR + 0x00) in this statement (PINSEL_BASE_ADDR + 0x00) is typecasts to volatile unsigned long pointer. But (*(volatile unsigned long *)(PINSEL_BASE_ADDR + 0x00)) , what is for the starting star(dereferencing operator) after first bracket.

 

[jayanth.devarayanadurga]

If I am wrong then correct me.

#define PINSEL_BASE_ADDR 0xE002C000

means PINSEL_BASE_ADDR is given the value 0xE002C000

PINSEL_BASE_ADDR holds some base address 0xE002C000

(volatile unsigned long *)(PINSEL_BASE_ADDR + 0x00) means

you are making the memory location 0xE002C000 + 0x00 as a pointer to volatile unsigne long type. It means the address stored at address 0xE002C000 points to a volatile unsigned long integer.

#define PINSEL0 (*(volatile unsigned long *)(PINSEL_BASE_ADDR + 0x00)) means you are dereferencing (volatile unsigned long *)(PINSEL_BASE_ADDR + 0x00) to get the volatile unsigned long int value pointed to by the pointer and making it an alias for PINSEL0