Re: [PATCH v3] target/riscv: Fix the element agnostic function problem

[Alistair Francis]

On Mon, Mar 25, 2024 at 12:18 PM Huang Tao <eric.huang@linux.alibaba.com> wrote:
>
> In RVV and vcrypto instructions, the masked and tail elements are set to 1s
> using vext_set_elems_1s function if the vma/vta bit is set. It is the element
> agnostic policy.
>
> However, this function can't deal the big endian situation. This patch fixes
> the problem by adding handling of such case.
>
> Signed-off-by: Huang Tao <eric.huang@linux.alibaba.com>
> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>

Thanks!

Applied to riscv-to-apply.next

Alistair

> ---
> Changes in v3:
> - use "if (HOST_BIG_ENDIAN)" instead of "#if HOST_BIG_ENDIAN"
>
> Changes in v2:
> - Keep the api of vext_set_elems_1s
> - Reduce the number of patches.
> ---
>  target/riscv/vector_internals.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/target/riscv/vector_internals.c b/target/riscv/vector_internals.c
> index 12f5964fbb..36635a1138 100644
> --- a/target/riscv/vector_internals.c
> +++ b/target/riscv/vector_internals.c
> @@ -30,6 +30,28 @@ void vext_set_elems_1s(void *base, uint32_t is_agnostic, 
> uint32_t cnt,
>      if (tot - cnt == 0) {
>          return ;
>      }
> +
> +    if (HOST_BIG_ENDIAN) {
> +        /*
> +         * Deal the situation when the elements are insdie
> +         * only one uint64 block including setting the
> +         * masked-off element.
> +         */
> +        if (((tot - 1) ^ cnt) < 8) {
> +            memset(base + H1(tot - 1), -1, tot - cnt);
> +            return;
> +        }
> +        /*
> +         * Otherwise, at least cross two uint64_t blocks.
> +         * Set first unaligned block.
> +         */
> +        if (cnt % 8 != 0) {
> +            uint32_t j = ROUND_UP(cnt, 8);
> +            memset(base + H1(j - 1), -1, j - cnt);
> +            cnt = j;
> +        }
> +        /* Set other 64bit aligend blocks */
> +    }
>      memset(base + cnt, -1, tot - cnt);
>  }
>
> --
> 2.41.0
>
>