Re: [kvm-unit-tests PATCH] s390x: Use loop to save and restore fprs

[Thomas Huth <thuth@redhat.com>]

On 04/11/2019 09.55, Janosch Frank wrote:
> Let's save some lines in the assembly by using a loop to save and
> restore the fprs.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>   s390x/cstart64.S | 38 ++++++--------------------------------
>   1 file changed, 6 insertions(+), 32 deletions(-)
> 
> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
> index 5dc1577..8e2b21e 100644
> --- a/s390x/cstart64.S
> +++ b/s390x/cstart64.S
> @@ -99,44 +99,18 @@ memsetxc:
>   	lctlg	%c0, %c0, 0(%r1)
>   	/* save fprs 0-15 + fpc */
>   	la	%r1, GEN_LC_SW_INT_FPRS
> -	std	%f0, 0(%r1)
> -	std	%f1, 8(%r1)
> -	std	%f2, 16(%r1)
> -	std	%f3, 24(%r1)
> -	std	%f4, 32(%r1)
> -	std	%f5, 40(%r1)
> -	std	%f6, 48(%r1)
> -	std	%f7, 56(%r1)
> -	std	%f8, 64(%r1)
> -	std	%f9, 72(%r1)
> -	std	%f10, 80(%r1)
> -	std	%f11, 88(%r1)
> -	std	%f12, 96(%r1)
> -	std	%f13, 104(%r1)
> -	std	%f14, 112(%r1)
> -	std	%f15, 120(%r1)
> +	.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
> +	std	\i, \i * 8(%r1)
> +	.endr
>   	stfpc	GEN_LC_SW_INT_FPC
>   	.endm
>   
>   	.macro RESTORE_REGS
>   	/* restore fprs 0-15 + fpc */
>   	la	%r1, GEN_LC_SW_INT_FPRS
> -	ld	%f0, 0(%r1)
> -	ld	%f1, 8(%r1)
> -	ld	%f2, 16(%r1)
> -	ld	%f3, 24(%r1)
> -	ld	%f4, 32(%r1)
> -	ld	%f5, 40(%r1)
> -	ld	%f6, 48(%r1)
> -	ld	%f7, 56(%r1)
> -	ld	%f8, 64(%r1)
> -	ld	%f9, 72(%r1)
> -	ld	%f10, 80(%r1)
> -	ld	%f11, 88(%r1)
> -	ld	%f12, 96(%r1)
> -	ld	%f13, 104(%r1)
> -	ld	%f14, 112(%r1)
> -	ld	%f15, 120(%r1)
> +	.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
> +	ld	\i, \i * 8(%r1)
> +	.endr
>   	lfpc	GEN_LC_SW_INT_FPC
>   	/* restore cr0 */
>   	lctlg	%c0, %c0, GEN_LC_SW_INT_CR0
> 

Produces exactly the same code as before.

Tested-by: Thomas Huth <thuth@redhat.com>