[Mesa-dev] [PATCH 26/29] mesa: Use bitmask/ffs to iterate the enabled textures.

[Mathias.Froehlich at gmx.net]

From: Mathias Fröhlich <mathias.froehlich at web.de>

Replaces an iterate and test bit in a bitmask loop by a
loop only iterating over the bits set in the bitmask.

v2: Use _mesa_bit_scan{,64} instead of open coding.
v3: Use u_bit_scan{,64} instead of _mesa_bit_scan{,64}.

Reviewed-by: Brian Paul <brianp at vmware.com>
Signed-off-by: Mathias Fröhlich <Mathias.Froehlich at web.de>
---
 src/mesa/main/texstate.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index 3543369..94caf2a 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -38,6 +38,7 @@
 #include "teximage.h"
 #include "texstate.h"
 #include "mtypes.h"
+#include "util/bitscan.h"
 #include "util/bitset.h"
 
 
@@ -611,7 +612,7 @@ update_ff_texture_state(struct gl_context *ctx,
 
    for (unit = 0; unit < ctx->Const.MaxTextureUnits; unit++) {
       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
-      GLuint texIndex;
+      GLbitfield mask;
       bool complete;
 
       if (texUnit->Enabled == 0x0)
@@ -651,20 +652,20 @@ update_ff_texture_state(struct gl_context *ctx,
        *      undefined."
        */
       complete = false;
-      for (texIndex = 0; texIndex < NUM_TEXTURE_TARGETS; texIndex++) {
-         if (texUnit->Enabled & (1 << texIndex)) {
-            struct gl_texture_object *texObj = texUnit->CurrentTex[texIndex];
-            struct gl_sampler_object *sampler = texUnit->Sampler ?
-               texUnit->Sampler : &texObj->Sampler;
-
-            if (!_mesa_is_texture_complete(texObj, sampler)) {
-               _mesa_test_texobj_completeness(ctx, texObj);
-            }
-            if (_mesa_is_texture_complete(texObj, sampler)) {
-               _mesa_reference_texobj(&texUnit->_Current, texObj);
-               complete = true;
-               break;
-            }
+      mask = texUnit->Enabled;
+      while (mask) {
+         const int texIndex = u_bit_scan(&mask);
+         struct gl_texture_object *texObj = texUnit->CurrentTex[texIndex];
+         struct gl_sampler_object *sampler = texUnit->Sampler ?
+            texUnit->Sampler : &texObj->Sampler;
+
+         if (!_mesa_is_texture_complete(texObj, sampler)) {
+            _mesa_test_texobj_completeness(ctx, texObj);
+         }
+         if (_mesa_is_texture_complete(texObj, sampler)) {
+            _mesa_reference_texobj(&texUnit->_Current, texObj);
+            complete = true;
+            break;
          }
       }
 
-- 
2.5.5