[U-Boot] [PATCH v2] arm: use common instructions applicable to armv7m & other arm archs

[Heiko Schocher]

Hello Vikas,

Am 04.02.2016 um 21:41 schrieb Vikas Manocha:
> This patch cleans the code by using instructions allowed for armv7m as well as
> other Arm archs.
>
> Signed-off-by: Vikas Manocha <vikas.manocha at st.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> ---
> Changes in v2: reword message commit. Removed info regarding BIC
> instruction on SP, was creating confusion.
>
>   arch/arm/lib/crt0.S | 25 +++++++------------------
>   1 file changed, 7 insertions(+), 18 deletions(-)
>
> diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
> index 2f4c14e..3731d0c 100644
> --- a/arch/arm/lib/crt0.S
> +++ b/arch/arm/lib/crt0.S
> @@ -71,18 +71,12 @@ ENTRY(_main)
>    */
>
>   #if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
> -	ldr	sp, =(CONFIG_SPL_STACK)
> +	ldr	r0, =(CONFIG_SPL_STACK)
>   #else
> -	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
> +	ldr	r0, =(CONFIG_SYS_INIT_SP_ADDR)
>   #endif
> -#if defined(CONFIG_CPU_V7M)	/* v7M forbids using SP as BIC destination */
> -	mov	r3, sp
> -	bic	r3, r3, #7
> -	mov	sp, r3
> -#else
> -	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
> -#endif
> -	mov	r0, sp
> +	bic	r0, r0, #7	/* 8-byte alignment for ABI compliance */
> +	mov	sp, r0
>   	bl	board_init_f_alloc_reserve
>   	mov	sp, r0
>   	/* set up gd here, outside any C code */
> @@ -100,14 +94,9 @@ ENTRY(_main)
>    * 'here' but relocated.
>    */
>
> -	ldr	sp, [r9, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
> -#if defined(CONFIG_CPU_V7M)	/* v7M forbids using SP as BIC destination */
> -	mov	r3, sp
> -	bic	r3, r3, #7
> -	mov	sp, r3
> -#else
> -	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
> -#endif
> +	ldr	r0, [r9, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
> +	bic	r0, r0, #7
> +	mov	sp, r0		/* 8-byte alignment for ABI compliance */

Why do you move this comment to the mov instruction? the "bic r0, r0, #7"
does the 8-byte alignment ... please add this comment to this line,
thanks!

>   	ldr	r9, [r9, #GD_BD]		/* r9 = gd->bd */
>   	sub	r9, r9, #GD_SIZE		/* new GD is below bd */

Beside of this nitpick:
Reviewed-by: Heiko Schocher <hs at denx.de>

bye,
Heiko
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