target/arm: Some SVE2p1 fixes

[PATCH for-10.1 10/10] target/arm: Make LD1Q decode and trans fn agree about a->u

Posted by Peter Maydell 3 months, 4 weeks ago

For the LD1Q instruction (gather load of quadwords) we use the
LD1_zprz pattern with MO_128 elements.  At this element size there is
no signed vs unsigned distinction, and we only set the 'u' bit in the
arg_LD1_zprz struct because we share the code and decode struct with
smaller element sizes.

However, we set u=0 in the decode pattern line but then accidentally
asserted that it was 1 in the trans function.  Since our usual convention
is that the "default" is unsigned and we only mark operations as signed
when they really do need to extend, change the decode pattern line to
set u=1 to match the assert.

Fixes: d2aa9a804ee6 ("target/arm: Implement LD1Q, ST1Q for SVE2p1")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/sve.decode | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/arm/tcg/sve.decode b/target/arm/tcg/sve.decode
index a77b725c876..aea7f519730 100644
--- a/target/arm/tcg/sve.decode
+++ b/target/arm/tcg/sve.decode
@@ -1345,7 +1345,7 @@ LD1_zprz        1100010 11 1. ..... 11. ... ..... ..... \
 
 # LD1Q
 LD1_zprz        1100 0100 000 rm:5 101 pg:3 rn:5 rd:5 \
-                &rprr_gather_load u=0 ff=0 xs=2 esz=4 msz=4 scale=0
+                &rprr_gather_load u=1 ff=0 xs=2 esz=4 msz=4 scale=0
 
 # SVE 64-bit gather load (vector plus immediate)
 LD1_zpiz        1100010 .. 01 ..... 1.. ... ..... ..... \
-- 
2.43.0

Re: [PATCH for-10.1 10/10] target/arm: Make LD1Q decode and trans fn agree about a->u

Posted by Richard Henderson 3 months, 4 weeks ago

On 7/18/25 10:30, Peter Maydell wrote:
> For the LD1Q instruction (gather load of quadwords) we use the
> LD1_zprz pattern with MO_128 elements.  At this element size there is
> no signed vs unsigned distinction, and we only set the 'u' bit in the
> arg_LD1_zprz struct because we share the code and decode struct with
> smaller element sizes.
> 
> However, we set u=0 in the decode pattern line but then accidentally
> asserted that it was 1 in the trans function.  Since our usual convention
> is that the "default" is unsigned and we only mark operations as signed
> when they really do need to extend, change the decode pattern line to
> set u=1 to match the assert.
> 
> Fixes: d2aa9a804ee6 ("target/arm: Implement LD1Q, ST1Q for SVE2p1")
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   target/arm/tcg/sve.decode | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/arm/tcg/sve.decode b/target/arm/tcg/sve.decode
> index a77b725c876..aea7f519730 100644
> --- a/target/arm/tcg/sve.decode
> +++ b/target/arm/tcg/sve.decode
> @@ -1345,7 +1345,7 @@ LD1_zprz        1100010 11 1. ..... 11. ... ..... ..... \
>   
>   # LD1Q
>   LD1_zprz        1100 0100 000 rm:5 101 pg:3 rn:5 rd:5 \
> -                &rprr_gather_load u=0 ff=0 xs=2 esz=4 msz=4 scale=0
> +                &rprr_gather_load u=1 ff=0 xs=2 esz=4 msz=4 scale=0
>   
>   # SVE 64-bit gather load (vector plus immediate)
>   LD1_zpiz        1100010 .. 01 ..... 1.. ... ..... ..... \

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~