6.2.1 Data Type Storage

Table 6-2 lists register and memory storage for various data types:

Table 6-2 Data Representation in Registers and Memory

Data Type	Register Storage	Memory Storage
char, signed char	Bits 0-7 of register⁽¹⁾	8 bits aligned to 8-bit boundary
unsigned char, bool	Bits 0-7 of register	8 bits aligned to 8-bit boundary
short, signed short	Bits 0-15 of register⁽¹⁾	16 bits aligned to 16-bit (halfword) boundary
unsigned short, wchar_t	Bits 0-15 of register	16 bits aligned to 16-bit (halfword) boundary
int, signed int	Bits 0-31 of register	32 bits aligned to 32-bit (word) boundary
unsigned int	Bits 0-31 of register	32 bits aligned to 32-bit (word) boundary
long, signed long	Bits 0-31 of register	32 bits aligned to 32-bit (word) boundary
unsigned long	Bits 0-31 of register	32 bits aligned to 32-bit (word) boundary
long long	Even/odd register pair	64 bits aligned to 32-bit (word) boundary⁽²⁾
unsigned long long	Even/odd register pair	64 bits aligned to 32-bit (word) boundary⁽²⁾
float	Bits 0-31 of register	32 bits aligned to 32-bit (word) boundary
double	Register pair	64 bits aligned to 32-bit (word) boundary⁽²⁾
long double	Register pair	64 bits aligned to 32-bit (word) boundary⁽²⁾
struct	Members are stored as their individual types require.	Members are stored as their individual types require; aligned according to the member with the most restrictive alignment requirement.
array	Members are stored as their individual types require.	Members are stored as their individual types require; aligned to 32-bit (word) boundary. All arrays inside a structure are aligned according to the type of each element in the array.
pointer to data member	Bits 0-31 of register	32 bits aligned to 32-bit (word) boundary
pointer to member function	Components stored as their individual types require	64 bits aligned to 32-bit (word) boundary

(1) Negative values are sign-extended to bit 31.

(2) 64-bit data is aligned on a 64-bit boundary.

For details about the size of an enum type, see Table 5-2.