> On Thu, Mar 22, 2012 at 08:54:49AM +0000, Havard Eidnes wrote:
>> Module Name: src
>> Committed By: he
>> Date: Thu Mar 22 08:54:48 UTC 2012
>>
>> Modified Files:
>> src/lib/libarch/alpha: alpha_pci_io.c
>>
>> Log Message:
>> Add a cast of the shift count to int32_t, so that we don't try
>> to do int32_t << long, since ANSI C doesn't perform "balancing"
>> before the shift operation according to lint. Should not make a
>> difference, offset is limited to 0..3 anyway.
>
> Again, why is this needed or desirable? Both sides of the operator are
> unsigned, so in the worst case, promition happens to the wider of the
> type and the result is truncated immediately. The casts are yet again
> just making the code uglier.
The comment in lint says:
/*
* ANSI C does not perform balancing for shift operations,
* but traditional C does. If the width of the right operand
* is greather than the width of the left operand, than in
* traditional C the left operand would be extendet to the
* width of the right operand. For SHL this may result in
* different results.
*/
and the corresponding warning from lint is
semantics of '<<' change in ANSI C; use explicit cast
So that's what I did.
If you think lint is wrong, I encourage you to improve it.
IMHO, as long as lint is capable of helping us spot actual
problems, adding a few of these sorts of constrcucts seems like a
small price to pay.
Regards,
- Håvard
