The enumerations are just log2(num_samples) shifted by 3, which we can
easily compute via ffs().
This also makes it reusable for Broadwell, which has 2x MSAA.
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
---
src/mesa/drivers/dri/i965/gen7_wm_surface_state.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/gen7_wm_surface_state.c
b/src/mesa/drivers/dri/i965/gen7_wm_surface_state.c
index 12d0fa9..154a0fd 100644
--- a/src/mesa/drivers/dri/i965/gen7_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_wm_surface_state.c
@@ -82,12 +82,10 @@ gen7_surface_msaa_bits(unsigned num_samples, enum
intel_msaa_layout layout)
{
uint32_t ss4 = 0;
- if (num_samples > 4)
- ss4 |= GEN7_SURFACE_MULTISAMPLECOUNT_8;
- else if (num_samples > 1)
- ss4 |= GEN7_SURFACE_MULTISAMPLECOUNT_4;
- else
- ss4 |= GEN7_SURFACE_MULTISAMPLECOUNT_1;
+ assert(num_samples <= 8);
+
+ /* The SURFACE_MULTISAMPLECOUNT_X enums are simply log2(num_samples) << 3.
*/
+ ss4 |= (ffs(MAX2(num_samples, 1)) - 1) << 3;
if (layout == INTEL_MSAA_LAYOUT_IMS)
ss4 |= GEN7_SURFACE_MSFMT_DEPTH_STENCIL;
--
1.8.4.2
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