linux-kernel - Re: [PATCH] ARM: Use udiv/sdiv for __aeabi

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Date:	Fri, 08 Nov 2013 17:02:57 +0000
From:	Måns Rullgård <mans@...sr.com>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions

Stephen Boyd <sboyd@...eaurora.org> writes:

> +int __aeabi_idiv(int numerator, int denominator)
> +{
> +	if (static_key_false(&cpu_has_idiv)) {
> +		int ret;
> +
> +		asm volatile (
> +		".arch_extension idiv\n"
> +		"sdiv %0, %1, %2"
> +		: "=&r" (ret)

There is no need for the & in the output constraint.  Dropping it allows
using one of the source registers as destination which may sometimes be
beneficial.

> +		: "r" (numerator), "r" (denominator));
> +
> +		return ret;
> +	}
> +
> +	return ___aeabi_idiv(numerator, denominator);
> +}

-- 
Måns Rullgård
mans@...sr.com
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