i965: check-point commit of new constant buffer support

Currently, shader constants are stored in the GRF (loaded from the CURBE
prior to shader execution).  This severly limits the number of constants
and temps that we can support.

This new code will support (practically) unlimited size constant buffers
and free up registers in the GRF.  We allocate a new buffer object for the
constants and read them with "Read" messages/instructions.  When only a
small number of constants are used, we can still use the old method.

The code works for fragment shaders only (and is actually disabled) for now.
Need to do the same thing for vertex shaders and need to add the necessary
code-gen to fetch the constants which are referenced by the shader
instructions.

1 files changed, 31 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_curbe.c b/src/mesa/drivers/dri/i965/brw_curbe.c
index 545dedd34b..39a8610952 100644
--- a/src/mesa/drivers/dri/i965/brw_curbe.c
+++ b/src/mesa/drivers/dri/i965/brw_curbe.c
@@ -38,6 +38,7 @@
 #include "shader/prog_parameter.h"
 #include "shader/prog_statevars.h"
 #include "intel_batchbuffer.h"
+#include "intel_regions.h"
 #include "brw_context.h"
 #include "brw_defines.h"
 #include "brw_state.h"
@@ -251,6 +252,7 @@ static void prepare_constant_buffer(struct brw_context *brw)
 
       _mesa_load_state_parameters(ctx, vp->program.Base.Parameters); 
 
+      /* XXX just use a memcpy here */
       for (i = 0; i < nr; i++) {
          const GLfloat *value = vp->program.Base.Parameters->ParameterValues[i];
 	 buf[offset + i * 4 + 0] = value[0];
@@ -330,11 +332,40 @@ static void prepare_constant_buffer(struct brw_context *brw)
 }
 
 
+/**
+ * Vertex/fragment shader constants are stored in a pseudo 1D texture.
+ * This function updates the constants in that buffer.
+ */
+static void
+update_texture_constant_buffer(struct brw_context *brw)
+{
+   struct intel_context *intel = &brw->intel;
+   struct brw_fragment_program *fp =
+      (struct brw_fragment_program *) brw->fragment_program;
+   const struct gl_program_parameter_list *params = fp->program.Base.Parameters;
+   const int size = params->NumParameters * 4 * sizeof(GLfloat);
+
+   assert(fp->const_buffer);
+   assert(fp->const_buffer->size >= size);
+
+   /* copy constants into the buffer */
+   if (size > 0) {
+      GLubyte *map;
+      dri_bo_map(fp->const_buffer, GL_TRUE);
+      map = fp->const_buffer->virtual;
+      memcpy(map, params->ParameterValues, size);
+      dri_bo_unmap(fp->const_buffer);
+   }
+}
+
+
 static void emit_constant_buffer(struct brw_context *brw)
 {
    struct intel_context *intel = &brw->intel;
    GLuint sz = brw->curbe.total_size;
 
+   update_texture_constant_buffer(brw);
+
    BEGIN_BATCH(2, IGNORE_CLIPRECTS);
    if (sz == 0) {
       OUT_BATCH((CMD_CONST_BUFFER << 16) | (2 - 2));