From 6eeae17c02267c57ba3f9f2ace6252fb50dbc9ec Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Mon, 10 Feb 2014 11:06:03 -0800 Subject: [PATCH] i965: Use ffs() for sample counting in gen7_surface_msaa_bits(). 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 Reviewed-by: Eric Anholt Reviewed-by: Anuj Phogat --- 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 12d0fa9de58..154a0fdd83c 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; -- 2.30.2