i965: comments

diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c
index 7909fd6..90d74c2 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -105,12 +105,17 @@ brw_wm_non_glsl_emit(struct brw_context *brw, struct brw_wm_compile *c)
    brw_wm_pass1(c);
 
    /* Register allocation.
+    * Divide by two because we operate on 16 pixels at a time and require
+    * two GRF entries for each logical shader register.
     */
    c->grf_limit = BRW_WM_MAX_GRF / 2;
 
    brw_wm_pass2(c);
 
+   /* how many general-purpose registers are used */
    c->prog_data.total_grf = c->max_wm_grf;
+
+   /* Scratch space is used for register spilling */
    if (c->last_scratch) {
       c->prog_data.total_scratch = c->last_scratch + 0x40;
    }