From: walter harms <wharms@bfs.de>
To: Colin Ian King <colin.king@canonical.com>
Cc: Takashi Iwai <tiwai@suse.de>,
alsa-devel@alsa-project.org, Jaroslav Kysela <perex@perex.cz>,
kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: synth: emux: remove redundant test for r <= 13
Date: Fri, 17 Nov 2017 12:11:12 +0100 [thread overview]
Message-ID: <5A0EC3D0.6020101@bfs.de> (raw)
In-Reply-To: <8de4b3a4-9ab4-3d23-6664-afffb28d864e@canonical.com>
Am 17.11.2017 12:07, schrieb Colin Ian King:
> On 17/11/17 11:06, Takashi Iwai wrote:
>> On Tue, 14 Nov 2017 18:26:53 +0100,
>> Colin King wrote:
>>>
>>> From: Colin Ian King <colin.king@canonical.com>
>>>
>>> The calculation r = (3 - ((rate >> 6) & 3)) * 3 results in r being
>>> 0, 3, 6 or 9 and so the check (13 > r) is always true and hence we
>>> can remove the redundant check and the else path.
>>>
>>> Detected by CoverityScan, CID#744415 ("Logically dead code")
>>>
>>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>>
>> The calculation of t itself can be generic in case we may add a
>> support greater than the current r, so I don't think it's so much
>> beneficial with this code reduction. Better to keep the code as
>> reference.
>
> OK, that's a good decision.
>
NTL is should be documented that this is intentional before the next
scanner finds it.
just my 2 cents,
re,
wh
> Colin
>>
>>
>> thanks,
>>
>> Takashi
>>
>>> ---
>>> sound/synth/emux/soundfont.c | 5 +----
>>> 1 file changed, 1 insertion(+), 4 deletions(-)
>>>
>>> diff --git a/sound/synth/emux/soundfont.c b/sound/synth/emux/soundfont.c
>>> index 31a4ea94830e..0beb5a737c8b 100644
>>> --- a/sound/synth/emux/soundfont.c
>>> +++ b/sound/synth/emux/soundfont.c
>>> @@ -858,10 +858,7 @@ calc_gus_envelope_time(int rate, int start, int end)
>>> p = rate & 0x3f;
>>> t = end - start;
>>> if (t < 0) t = -t;
>>> - if (13 > r)
>>> - t = t << (13 - r);
>>> - else
>>> - t = t >> (r - 13);
>>> + t = t << (13 - r);
>>> return (t * 10) / (p * 441);
>>> }
>>>
>>> --
>>> 2.14.1
>>>
>>>
>> --
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>
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prev parent reply other threads:[~2017-11-17 11:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-14 17:26 [PATCH] ALSA: synth: emux: remove redundant test for r <= 13 Colin King
2017-11-17 11:06 ` Takashi Iwai
2017-11-17 11:07 ` Colin Ian King
2017-11-17 11:11 ` walter harms [this message]
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