[Mesa-dev] [PATCH 01/13] i965: Simplify Broadwell's 3DSTATE_MULTISAMPLE sample count handling.

[Anuj Phogat]

On Wed, Feb 19, 2014 at 2:04 AM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> These enumerations are simply log2 of the number of multisamples shifted
> by a bit, so we can calculate them using ffs() in a lot less code.
>
> Suggested by Eric Anholt.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/mesa/drivers/dri/i965/gen8_multisample_state.c | 26 +++-------------------
>  1 file changed, 3 insertions(+), 23 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/gen8_multisample_state.c b/src/mesa/drivers/dri/i965/gen8_multisample_state.c
> index 64c7208..bfe0d5b 100644
> --- a/src/mesa/drivers/dri/i965/gen8_multisample_state.c
> +++ b/src/mesa/drivers/dri/i965/gen8_multisample_state.c
> @@ -33,33 +33,13 @@
>  void
>  gen8_emit_3dstate_multisample(struct brw_context *brw, unsigned num_samples)
>  {
> -   uint32_t number_of_multisamples = 0;
> +   assert(num_samples <= 16);
>
> -   switch (num_samples) {
> -   case 0:
> -   case 1:
> -      number_of_multisamples = MS_NUMSAMPLES_1;
> -      break;
> -   case 2:
> -      number_of_multisamples = MS_NUMSAMPLES_2;
> -      break;
> -   case 4:
> -      number_of_multisamples = MS_NUMSAMPLES_4;
> -      break;
> -   case 8:
> -      number_of_multisamples = MS_NUMSAMPLES_8;
> -      break;
> -   case 16:
> -      number_of_multisamples = MS_NUMSAMPLES_16;
> -      break;
> -   default:
> -      assert(!"Unrecognized num_samples in gen8_emit_3dstate_multisample");
> -      break;
> -   }
> +   unsigned log2_samples = ffs(MAX2(num_samples, 1)) - 1;
>
>     BEGIN_BATCH(2);
>     OUT_BATCH(GEN8_3DSTATE_MULTISAMPLE << 16 | (2 - 2));
> -   OUT_BATCH(MS_PIXEL_LOCATION_CENTER | number_of_multisamples);
> +   OUT_BATCH(MS_PIXEL_LOCATION_CENTER | log2_samples << 1);
>     ADVANCE_BATCH();
>  }
>
> --
> 1.8.4.2
>
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This series is:
Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>