[Mesa-dev] [PATCH 17/29] mesa: Use bitmask/ffs to build ff vertex shader keys.

[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.
The bitmask used here for iteration is a combination
of different enabled masks present for texture units.

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/ffvertex_prog.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/mesa/main/ffvertex_prog.c b/src/mesa/main/ffvertex_prog.c
index ca72554..f4ae690 100644
--- a/src/mesa/main/ffvertex_prog.c
+++ b/src/mesa/main/ffvertex_prog.c
@@ -150,7 +150,6 @@ static void make_state_key( struct gl_context *ctx, struct state_key *key )
 {
    const struct gl_fragment_program *fp;
    GLbitfield mask;
-   GLuint i;
 
    memset(key, 0, sizeof(struct state_key));
    fp = ctx->FragmentProgram._Current;
@@ -238,7 +237,10 @@ static void make_state_key( struct gl_context *ctx, struct state_key *key )
        ctx->Texture._MaxEnabledTexImageUnit != -1)
       key->texture_enabled_global = 1;
 
-   for (i = 0; i < MAX_TEXTURE_COORD_UNITS; i++) {
+   mask = ctx->Texture._EnabledCoordUnits | ctx->Texture._TexGenEnabled
+      | ctx->Texture._TexMatEnabled | ctx->Point.CoordReplace;
+   while (mask) {
+      const int i = u_bit_scan(&mask);
       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[i];
 
       if (texUnit->_Current)
-- 
2.5.5