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Subject: Re: [PATCH v1 1/2] vsprintf: introduce %dE for error constants
To:     =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <uwe@kleine-koenig.org>,
        Andrew Morton <akpm@linux-foundation.org>
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        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>
References: <20190824233724.1775-1-uwe@kleine-koenig.org>
From:   "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Organization: metux IT consult
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Date:   Mon, 26 Aug 2019 15:29:08 +0200
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On 25.08.19 01:37, Uwe Kleine-König wrote:

Hi,

> +static noinline_for_stack > +char *errstr(char *buf, char *end, unsigned long long num,> +	 
struct printf_spec spec)> +{
#1: why not putting that into some separate strerror() lib function ?
     This is something I've been looking for quite some time (actually
     already hacked it up somewhere, sometime, but forgotten ...)

#2: why not just having a big case statement and leave the actual lookup
     logic to the compiler ? IMHO, could be written in a very compact way
     by some macro magic

> +	for (i = 0; i < ARRAY_SIZE(errorcodes); ++i) { > +		if (num == errorcodes[i].err || num == -errorcodes[i].err) {

why not taking the abs value only once, instead of duplicate comp on
each iteration ?


--mtx

-- 
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@metux.net -- +49-151-27565287