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

[Vikas MANOCHA]

Thanks Heiko,

> -----Original Message-----
> From: Heiko Schocher [mailto:hs at denx.de]
> Sent: Thursday, February 04, 2016 9:39 PM
> To: Vikas MANOCHA
> Cc: albert.u.boot at aribaud.net; Simon Glass; Przemyslaw Marczak; Heiko
> Schocher; rev13 at wp.pl; open list
> Subject: Re: [PATCH v2] arm: use common instructions applicable to armv7m
> & other arm archs
> 
> 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!

Ok, I will send v3 with this correction.

Cheers,
Vikas

> 
> >   	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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