From: Andrew Jones <ajones@ventanamicro.com>
To: zhangfei <zhang_fei_0403@163.com>
Cc: aou@eecs.berkeley.edu, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org, palmer@dabbelt.com,
paul.walmsley@sifive.com, zhangfei@nj.iscas.ac.cn,
conor.dooley@microchip.com
Subject: Re: [PATCH 1/2] RISC-V: lib: Improve memset assembler formatting
Date: Tue, 9 May 2023 11:48:33 +0200 [thread overview]
Message-ID: <20230509-b76dc35d2a84d96806496c8e@orel> (raw)
In-Reply-To: <20230509022207.3700-1-zhang_fei_0403@163.com>
On Tue, May 09, 2023 at 10:22:05AM +0800, zhangfei wrote:
> From: Andrew Jones <ajones@ventanamicro.com>
>
> Aligning the first operand of each instructions with a tab is a
> typical style which improves readability. Apply it to memset.S.
> While there, we also make a small grammar change to a comment.
>
> No functional change intended.
>
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Please pick up Conor's r-b on this reposting.
Thanks,
drew
> ---
> arch/riscv/lib/memset.S | 143 ++++++++++++++++++++--------------------
> 1 file changed, 72 insertions(+), 71 deletions(-)
>
> diff --git a/arch/riscv/lib/memset.S b/arch/riscv/lib/memset.S
> index 34c5360c6705..e613c5c27998 100644
> --- a/arch/riscv/lib/memset.S
> +++ b/arch/riscv/lib/memset.S
> @@ -3,111 +3,112 @@
> * Copyright (C) 2013 Regents of the University of California
> */
>
> -
> #include <linux/linkage.h>
> #include <asm/asm.h>
>
> /* void *memset(void *, int, size_t) */
> ENTRY(__memset)
> WEAK(memset)
> - move t0, a0 /* Preserve return value */
> + move t0, a0 /* Preserve return value */
>
> /* Defer to byte-oriented fill for small sizes */
> - sltiu a3, a2, 16
> - bnez a3, 4f
> + sltiu a3, a2, 16
> + bnez a3, 4f
>
> /*
> * Round to nearest XLEN-aligned address
> - * greater than or equal to start address
> + * greater than or equal to the start address.
> */
> - addi a3, t0, SZREG-1
> - andi a3, a3, ~(SZREG-1)
> - beq a3, t0, 2f /* Skip if already aligned */
> + addi a3, t0, SZREG-1
> + andi a3, a3, ~(SZREG-1)
> + beq a3, t0, 2f /* Skip if already aligned */
> +
> /* Handle initial misalignment */
> - sub a4, a3, t0
> + sub a4, a3, t0
> 1:
> - sb a1, 0(t0)
> - addi t0, t0, 1
> - bltu t0, a3, 1b
> - sub a2, a2, a4 /* Update count */
> + sb a1, 0(t0)
> + addi t0, t0, 1
> + bltu t0, a3, 1b
> + sub a2, a2, a4 /* Update count */
>
> 2: /* Duff's device with 32 XLEN stores per iteration */
> /* Broadcast value into all bytes */
> - andi a1, a1, 0xff
> - slli a3, a1, 8
> - or a1, a3, a1
> - slli a3, a1, 16
> - or a1, a3, a1
> + andi a1, a1, 0xff
> + slli a3, a1, 8
> + or a1, a3, a1
> + slli a3, a1, 16
> + or a1, a3, a1
> #ifdef CONFIG_64BIT
> - slli a3, a1, 32
> - or a1, a3, a1
> + slli a3, a1, 32
> + or a1, a3, a1
> #endif
>
> /* Calculate end address */
> - andi a4, a2, ~(SZREG-1)
> - add a3, t0, a4
> + andi a4, a2, ~(SZREG-1)
> + add a3, t0, a4
>
> - andi a4, a4, 31*SZREG /* Calculate remainder */
> - beqz a4, 3f /* Shortcut if no remainder */
> - neg a4, a4
> - addi a4, a4, 32*SZREG /* Calculate initial offset */
> + andi a4, a4, 31*SZREG /* Calculate remainder */
> + beqz a4, 3f /* Shortcut if no remainder */
> + neg a4, a4
> + addi a4, a4, 32*SZREG /* Calculate initial offset */
>
> /* Adjust start address with offset */
> - sub t0, t0, a4
> + sub t0, t0, a4
>
> /* Jump into loop body */
> /* Assumes 32-bit instruction lengths */
> - la a5, 3f
> + la a5, 3f
> #ifdef CONFIG_64BIT
> - srli a4, a4, 1
> + srli a4, a4, 1
> #endif
> - add a5, a5, a4
> - jr a5
> + add a5, a5, a4
> + jr a5
> 3:
> - REG_S a1, 0(t0)
> - REG_S a1, SZREG(t0)
> - REG_S a1, 2*SZREG(t0)
> - REG_S a1, 3*SZREG(t0)
> - REG_S a1, 4*SZREG(t0)
> - REG_S a1, 5*SZREG(t0)
> - REG_S a1, 6*SZREG(t0)
> - REG_S a1, 7*SZREG(t0)
> - REG_S a1, 8*SZREG(t0)
> - REG_S a1, 9*SZREG(t0)
> - REG_S a1, 10*SZREG(t0)
> - REG_S a1, 11*SZREG(t0)
> - REG_S a1, 12*SZREG(t0)
> - REG_S a1, 13*SZREG(t0)
> - REG_S a1, 14*SZREG(t0)
> - REG_S a1, 15*SZREG(t0)
> - REG_S a1, 16*SZREG(t0)
> - REG_S a1, 17*SZREG(t0)
> - REG_S a1, 18*SZREG(t0)
> - REG_S a1, 19*SZREG(t0)
> - REG_S a1, 20*SZREG(t0)
> - REG_S a1, 21*SZREG(t0)
> - REG_S a1, 22*SZREG(t0)
> - REG_S a1, 23*SZREG(t0)
> - REG_S a1, 24*SZREG(t0)
> - REG_S a1, 25*SZREG(t0)
> - REG_S a1, 26*SZREG(t0)
> - REG_S a1, 27*SZREG(t0)
> - REG_S a1, 28*SZREG(t0)
> - REG_S a1, 29*SZREG(t0)
> - REG_S a1, 30*SZREG(t0)
> - REG_S a1, 31*SZREG(t0)
> - addi t0, t0, 32*SZREG
> - bltu t0, a3, 3b
> - andi a2, a2, SZREG-1 /* Update count */
> + REG_S a1, 0(t0)
> + REG_S a1, SZREG(t0)
> + REG_S a1, 2*SZREG(t0)
> + REG_S a1, 3*SZREG(t0)
> + REG_S a1, 4*SZREG(t0)
> + REG_S a1, 5*SZREG(t0)
> + REG_S a1, 6*SZREG(t0)
> + REG_S a1, 7*SZREG(t0)
> + REG_S a1, 8*SZREG(t0)
> + REG_S a1, 9*SZREG(t0)
> + REG_S a1, 10*SZREG(t0)
> + REG_S a1, 11*SZREG(t0)
> + REG_S a1, 12*SZREG(t0)
> + REG_S a1, 13*SZREG(t0)
> + REG_S a1, 14*SZREG(t0)
> + REG_S a1, 15*SZREG(t0)
> + REG_S a1, 16*SZREG(t0)
> + REG_S a1, 17*SZREG(t0)
> + REG_S a1, 18*SZREG(t0)
> + REG_S a1, 19*SZREG(t0)
> + REG_S a1, 20*SZREG(t0)
> + REG_S a1, 21*SZREG(t0)
> + REG_S a1, 22*SZREG(t0)
> + REG_S a1, 23*SZREG(t0)
> + REG_S a1, 24*SZREG(t0)
> + REG_S a1, 25*SZREG(t0)
> + REG_S a1, 26*SZREG(t0)
> + REG_S a1, 27*SZREG(t0)
> + REG_S a1, 28*SZREG(t0)
> + REG_S a1, 29*SZREG(t0)
> + REG_S a1, 30*SZREG(t0)
> + REG_S a1, 31*SZREG(t0)
> +
> + addi t0, t0, 32*SZREG
> + bltu t0, a3, 3b
> + andi a2, a2, SZREG-1 /* Update count */
>
> 4:
> /* Handle trailing misalignment */
> - beqz a2, 6f
> - add a3, t0, a2
> + beqz a2, 6f
> + add a3, t0, a2
> 5:
> - sb a1, 0(t0)
> - addi t0, t0, 1
> - bltu t0, a3, 5b
> + sb a1, 0(t0)
> + addi t0, t0, 1
> + bltu t0, a3, 5b
> 6:
> ret
> END(__memset)
> --
> 2.33.0
>
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prev parent reply other threads:[~2023-05-09 9:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-05 8:43 [PATCH] riscv: Optimize memset 张飞
2023-05-05 11:54 ` Andrew Jones
2023-05-09 2:22 ` [PATCH 1/2] RISC-V: lib: Improve memset assembler formatting zhangfei
2023-05-09 2:22 ` [PATCH 2/2] riscv: Optimize memset zhangfei
2023-05-09 2:22 ` Re: [PATCH] " zhangfei
2023-05-09 9:16 ` Andrew Jones
2023-05-10 3:52 ` [PATCH 0/2] riscv: Optimize memset for data sizes less than 16 bytes zhangfei
2023-05-10 3:52 ` [PATCH 1/2] RISC-V: lib: Improve memset assembler formatting zhangfei
2023-05-10 7:13 ` Conor Dooley
2023-05-11 1:55 ` zhangfei
2023-05-10 3:52 ` [PATCH 2/2] riscv: Optimize memset zhangfei
2023-05-10 3:52 ` [PATCH] " zhangfei
2023-05-10 6:58 ` Andrew Jones
2023-05-11 1:42 ` zhangfei
2023-05-09 9:48 ` Andrew Jones [this message]
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