Re: [PATCH 1/2] RISC-V: lib: Improve memset assembler formatting

[Andrew Jones]

On Tue, May 09, 2023 at 10:22:05AM +0800, zhangfei wrote:
> From: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
> 
> 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@xxxxxxxxxxxxxxxx>

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
>