Re: [Qemu-devel] [PULL 00/11] Ide patches

[Peter Maydell]

On 11 January 2016 at 17:18, John Snow <address@hidden> wrote:
> On 01/11/2016 06:18 AM, Peter Maydell wrote:
>> On 9 January 2016 at 00:51, John Snow <address@hidden> wrote:
>> This kind of thing:
>>
>
> "This kind of thing" as one might say while holding up a rotting fish
> with just two fingers, held at arm's length.

Not the intended tone :-)

>>     unsigned char *cbd = cmd->atapi_cmd;
>>     uint32_t *lba32;
>>
>>         lba32 = (uint32_t *)&(cbd[2]);
>>         *lba32 = cpu_to_be32(lba);
>>
>> isn't valid. You probably want
>>  stl_be_p(&cbd[2], lba);

> Thanks for the pointer. Out of curiosity, is there no standard way to
> perform this kind of operation in C? I want to adjust my bad habits. In
> QEMU I can remember to use these macros now that I know they're there,
> but not sure what I'd use in other projects. memcpy directly?

You can use memcpy, or you can hand-assemble values in and out
of byte arrays, I think. memcpy() is generally recommended, because
the compiler does a decent job with it.

thanks
-- PMM