Atmel CAVR-4 Manual De Usuario

CAVR-4

Pointer types

Reference Guide

Casts between pointers have the following characteristics:

●

Casting a value of an integer type to a pointer of a smaller type is performed by 
truncation

●

Casting a value of an integer type to a pointer of a larger type is performed by zero 
extension

●

Casting a pointer type to a smaller integer type is performed by truncation

●

Casting a pointer type to a larger integer type is performed via casting to the largest 
possible pointer that fits in the integer

●

Casting a data pointer to a function pointer and vice versa is illegal

●

Casting a function pointer to an integer type gives an undefined result.

size_t

 is the unsigned integer type required to hold the maximum size of an object. 

The following table shows the 

typedef

 of 

size_t

 depending on the processor option:

_ _farflash

3 bytes

Code

signed int

0x0–0xFFFFFF

 

(16-bit arithmetics)

_ _hugeflash

3 bytes

Code

signed long 0x0–0xFFFFFF

_ _eeprom

1 byte

EEPROM

signed char 0x0–0xFF

_ _eeprom

2 bytes

EEPROM

signed int

0x0–0xFFFF

_ _generic

2 bytes

3 bytes

Data/Code

signed int 

signed long

The most significant bit (MSB) 

determines whether __generic 

points to CODE (1) or DATA (0). The 

small generic pointer is generated 

for the processor options -v0 and 

-v1

.

-v0

 and -v1

unsigned

 int

-v2

, -v3, -v4, -v5, and -v6

unsigned

 long