Re: [PATCH for-6.2 08/34] target/arm: Fix VPT advance when ECI is non-zero

[Richard Henderson]

On 7/13/21 6:37 AM, Peter Maydell wrote:
>       if (mask01 > 8) {
> -        /* high bit set, but not 0b1000: invert the relevant half of P0 */
> -        vpr ^= 0xff;
> +        if (eci == ECI_NONE) {
> +            /* high bit set, but not 0b1000: invert the relevant half of P0 */
> +            vpr ^= 0xff;
> +        } else if (eci == ECI_A0) {
> +            /* Invert only the beat 1 P0 bits, as we didn't execute beat 0 */
> +            vpr ^= 0xf0;
> +        } /* otherwise we didn't execute either beat 0 or beat 1 */
>       }
>       if (mask23 > 8) {
> -        /* high bit set, but not 0b1000: invert the relevant half of P0 */
> -        vpr ^= 0xff00;
> +        if (eci != ECI_A0A1A2 && eci != ECI_A0A1A2B0) {
> +            /* high bit set, but not 0b1000: invert the relevant half of P0 */
> +            vpr ^= 0xff00;
> +        } else {
> +            /* We didn't execute beat 2, only invert the beat 3 P0 bits */
> +            vpr ^= 0xf000;
> +        }
>       }

It might not be any cleaner, but I wondered if mve_eci_mask could help here.

  inv_mask = mve_eci_mask(...);
  if (mask01 <= 8) {
    inv_mask &= ~0xff;
  }
  if (mask23 <= 8) {
    inv_mask &= ~0xff00;
  }
  vpr ^= inv_mask;


r~