On Tue, 19 Jun 2001, Philip Andrew Ferguson wrote:
> Hello All,
>
> I have a quick question. What are the sizes of the following variable
> types in the ARM architecture?
>
> int
> long int
> short int
> float
> double
> char
For a quick reference:
try asking sizeof() ;-)
int: 4
long int: 4
long long int: 8
short int: 2
float: 4
double: 8
char: 1
char*: 4
But beware: structures have their own alignment rules!
Generally, structures are multiples of 4 bytes in size
and start on a 4 byte boundary.
The alignment of members within the structure depends on the
previous ones:
a new struct member starts at a boundary that is equivalent to it's
alignment requirements.
That is: a char may start at a byte boundary, a short will start on the
next even byte and larger types at the next new word.
There may be "holes" in the struct, like in the following example:
struct foo {
char foo1;
/* here is a 3 byte hole */
int foo2;
/* this fits well */
char foo3;
/* here comes a hole as well */
short foo4[3];
/* and here will be 2 bytes to close the struct */
}
Hope this helps.
sh
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