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From:   Andreas Schwab <schwab@linux-m68k.org>
To:     Akira Tsukamoto <akira.tsukamoto@gmail.com>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Qiu Wenbo <qiuwenbo@kylinos.com.cn>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] riscv: __asm_copy_to-from_user: Improve using word
 copy if size < 9*SZREG
References: <65f08f01-d4ce-75c2-030b-f8759003e061@gmail.com>
        <e3e9fb3a-40b1-50f3-23cc-50bfa53baa8d@gmail.com>
Date:   Sun, 15 Aug 2021 08:51:18 +0200
In-Reply-To: <e3e9fb3a-40b1-50f3-23cc-50bfa53baa8d@gmail.com> (Akira
        Tsukamoto's message of "Fri, 30 Jul 2021 22:52:44 +0900")
Message-ID: <87bl5z42vt.fsf@linux-m68k.org>
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On Jul 30 2021, Akira Tsukamoto wrote:

>  .Lword_copy:
> -        /*
> -	 * Both src and dst are aligned, unrolled word copy
> +	/*
> +	 * Both src and dst are aligned
> +	 * None unrolled word copy with every 1*SZREG iteration
> +	 *
> +	 * a0 - start of aligned dst
> +	 * a1 - start of aligned src
> +	 * t0 - end of aligned dst
> +	 */
> +	bgeu	a0, t0, .Lbyte_copy_tail /* check if end of copy */
> +	addi	t0, t0, -(SZREG) /* not to over run */
> +1:
> +	REG_L	a5, 0(a1)
> +	addi	a1, a1, SZREG
> +	REG_S	a5, 0(a0)
> +	addi	a0, a0, SZREG
> +	bltu	a0, t0, 1b

This is missing fixups.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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