Mihai "Don?u" <mihai.dontu@xxxxxxxxx> writes:
> On Wednesday 30 May 2007 13:00, Andrew Haley wrote:
>> Mihai Don?u writes:
>> > typedef struct _type2_t {
>> > union {
>> > uint32_t field1:31;
>> > uint32_t field2:16;
>> > };
>> > uint32_t field3:1;
>> > } __PACKED type2_t;
>>
>> I've read this three times now and I still don't understand your
>> question. You declare a packed struct, but you don't want it to be
>> packed? So don't declare it packed, then. But that can't be what you
>> really meant.
>>
>> Andrew.
>>
>
> Ok, I'm sorry if I wasn't clear.
>
> Let me begin with the problem that I'm facing: I have an array of dword-s
> where each dword has the following "bit-fields":
> * ordinal_or_name (bit 31, i.e. 0x80000000 )
> * ordinal (bits 0-15, i.e. 0x0000ffff)
> * name_rva (bits 0-30, i.e. 0x7fffffff)
The following might work for you, though be warned that C bitfields aren't
very suitable to represent data formats. For example, the code won't be
portable between big- and little-endian CPUs.
typedef struct ordinal {
uint32_t ord:16;
uint32_t reserved:15;
};
typedef struct name_rva {
uint32_t name:31;
uint32_t reserved:1:
};
typedef struct flag {
uint32_t reserved:31;
uint32_t flag:1;
};
typedef union fields {
flag f;
ordinal o;
name_rva n;
};
-- Sergei.
