cell: comments, etc.

3 files changed, 52 insertions, 25 deletions

diff --git a/src/gallium/drivers/cell/ppu/cell_state_per_fragment.c b/src/gallium/drivers/cell/ppu/cell_state_per_fragment.c
index 53ae3aa50e7..705867107bf 100644
--- a/src/gallium/drivers/cell/ppu/cell_state_per_fragment.c
+++ b/src/gallium/drivers/cell/ppu/cell_state_per_fragment.c
@@ -132,9 +132,9 @@ emit_alpha_test(struct pipe_depth_stencil_alpha_state *dsa,
 
 
 /**
+ * Generate code to perform Z testing.  Four Z values are tested at once.
  * \param dsa        Current depth-test state
  * \param f          Function to which code should be appended
- * \param m          Mask of allocated / free SPE registers
  * \param mask       Index of register to contain depth-pass mask
  * \param stored     Index of register containing values from depth buffer
  * \param calculated Index of register containing per-fragment depth values
@@ -198,6 +198,7 @@ emit_depth_test(struct pipe_depth_stencil_alpha_state *dsa,
 
 
 /**
+ * Generate code to apply the stencil operation (after testing).
  * \note Emits a maximum of 5 instructions.
  *
  * \warning
@@ -222,9 +223,13 @@ emit_stencil_op(struct spe_function *f,
       spe_il(f, result, ref);
       break;
    case PIPE_STENCIL_OP_INCR:
+      /* clamp = [0xff, 0xff, 0xff, 0xff] */
       spe_il(f, clamp, 0x0ff);
+      /* result[i] = in[i] + 1 */
       spe_ai(f, result, in, 1);
+      /* clamp_mask[i] = (result[i] > 0xff) */
       spe_clgti(f, clamp_mask, result, 0x0ff);
+      /* result[i] = clamp_mask[i] ? clamp[i] : result[i] */
       spe_selb(f, result, result, clamp, clamp_mask);
       break;
    case PIPE_STENCIL_OP_DECR:
@@ -259,10 +264,10 @@ emit_stencil_op(struct spe_function *f,
 
 
 /**
+ * Generate code to do stencil test.  Four pixels are tested at once.
  * \param dsa        Depth / stencil test state
  * \param face       0 for front face, 1 for back face
  * \param f          Function to append instructions to
- * \param reg_mask   Mask of allocated registers
  * \param mask       Register containing mask of fragments passing the
  *                   alpha test
  * \param depth_mask Register containing mask of fragments passing the
@@ -310,13 +315,14 @@ emit_stencil_test(struct pipe_depth_stencil_alpha_state *dsa,
 
    switch (dsa->stencil[face].func) {
    case PIPE_FUNC_NEVER:
-      spe_il(f, stencil_mask, 0);
+      spe_il(f, stencil_mask, 0);   /* stencil_mask[0..3] = [0,0,0,0] */
       break;
 
    case PIPE_FUNC_NOTEQUAL:
       complement = TRUE;
       /* FALLTHROUGH */
    case PIPE_FUNC_EQUAL:
+      /* stencil_mask[i] = (stored[i] == ref) */
       spe_ceqi(f, stencil_mask, stored, ref);
       break;
 
@@ -324,6 +330,8 @@ emit_stencil_test(struct pipe_depth_stencil_alpha_state *dsa,
       complement = TRUE;
       /* FALLTHROUGH */
    case PIPE_FUNC_GREATER:
+      complement = TRUE;
+      /* stencil_mask[i] = (stored[i] > ref) */
       spe_clgti(f, stencil_mask, stored, ref);
       break;
 
@@ -331,8 +339,11 @@ emit_stencil_test(struct pipe_depth_stencil_alpha_state *dsa,
       complement = TRUE;
       /* FALLTHROUGH */
    case PIPE_FUNC_GEQUAL:
+      /* stencil_mask[i] = (stored[i] > ref) */
       spe_clgti(f, stencil_mask, stored, ref);
+      /* tmp[i] = (stored[i] == ref) */
       spe_ceqi(f, tmp, stored, ref);
+      /* stencil_mask[i] = stencil_mask[i] | tmp[i] */
       spe_or(f, stencil_mask, stencil_mask, tmp);
       break;
 
@@ -461,7 +472,7 @@ cell_generate_depth_stencil_test(struct cell_depth_stencil_alpha_state *cdsa)
     * + 25 (front stencil) + 25 (back stencil) + 4 = 63 instructions.  Round
     * up to 64 to make it a happy power-of-two.
     */
-   spe_init_func(f, 4 * 64);
+   spe_init_func(f, SPE_INST_SIZE * 64);
 
 
    /* Allocate registers for the function's input parameters.  Cleverly (and
@@ -540,7 +551,7 @@ cell_generate_depth_stencil_test(struct cell_depth_stencil_alpha_state *cdsa)
          spe_selb(f, depth, depth, zvals, mask);
    }
 
-   spe_bi(f, 0, 0, 0);
+   spe_bi(f, 0, 0, 0);  /* return from function call */
 
 
 #if 0
@@ -956,7 +967,7 @@ cell_generate_alpha_blend(struct cell_blend_state *cb)
     * + 4 (fragment mask) + 1 (return) = 55 instlructions.  Round up to 64 to
     * make it a happy power-of-two.
     */
-   spe_init_func(f, 4 * 64);
+   spe_init_func(f, SPE_INST_SIZE * 64);
 
 
    const int frag[4] = {
@@ -1144,7 +1155,8 @@ cell_generate_alpha_blend(struct cell_blend_state *cb)
 }
 
 
-int PC_OFFSET(const struct spe_function *f, const void *d)
+static int
+PC_OFFSET(const struct spe_function *f, const void *d)
 {
    const intptr_t pc = (intptr_t) f->csr;
    const intptr_t ea = ~0x0f & (intptr_t) d;
@@ -1178,7 +1190,7 @@ cell_generate_logic_op(struct spe_function *f,
     * bytes (equiv. to 8 instructions) are needed for data storage.  Round up
     * to 64 to make it a happy power-of-two.
     */
-   spe_init_func(f, 4 * 64);
+   spe_init_func(f, SPE_INST_SIZE * 64);
 
 
    /* Pixel colors in framebuffer format in AoS layout.
diff --git a/src/gallium/drivers/cell/ppu/cell_vertex_fetch.c b/src/gallium/drivers/cell/ppu/cell_vertex_fetch.c
index 2ece0250f6f..566df7f59e3 100644
--- a/src/gallium/drivers/cell/ppu/cell_vertex_fetch.c
+++ b/src/gallium/drivers/cell/ppu/cell_vertex_fetch.c
@@ -297,10 +297,9 @@ void cell_update_vertex_fetch(struct draw_context *draw)
 
 
    /* Each fetch function can be a maximum of 34 instructions (note: this is
-    * actually a slight over-estimate).  That means (34 * 4) = 136 bytes
-    * each maximum.
+    * actually a slight over-estimate).
     */
-   spe_init_func(p, 136 * unique_attr_formats);
+   spe_init_func(p, 34 * SPE_INST_SIZE * unique_attr_formats);
 
 
    /* Allocate registers for the function's input parameters.
diff --git a/src/gallium/drivers/cell/spu/spu_per_fragment_op.c b/src/gallium/drivers/cell/spu/spu_per_fragment_op.c
index c0a729b3d2c..db887352265 100644
--- a/src/gallium/drivers/cell/spu/spu_per_fragment_op.c
+++ b/src/gallium/drivers/cell/spu/spu_per_fragment_op.c
@@ -35,8 +35,17 @@
 
 #define ZERO 0x80
 
+
+/**
+ * Get a "quad" of four fragment Z/stencil values from the given tile.
+ * \param tile  the tile of Z/stencil values
+ * \param x, y  location of the quad in the tile, in pixels
+ * \param depth_format  format of the tile's data
+ * \param detph  returns four depth values
+ * \param stencil  returns four stencil values
+ */
 static void
-read_ds_quad(tile_t *buffer, unsigned x, unsigned y,
+read_ds_quad(tile_t *tile, unsigned x, unsigned y,
              enum pipe_format depth_format, qword *depth,
              qword *stencil)
 {
@@ -45,14 +54,13 @@ read_ds_quad(tile_t *buffer, unsigned x, unsigned y,
 
    switch (depth_format) {
    case PIPE_FORMAT_Z16_UNORM: {
-      qword *ptr = (qword *) &buffer->us8[iy][ix / 2];
+      qword *ptr = (qword *) &tile->us8[iy][ix / 2];
 
       const qword shuf_vec = (qword) {
          ZERO, ZERO, 0, 1, ZERO, ZERO, 2, 3,
          ZERO, ZERO, 4, 5, ZERO, ZERO, 6, 7
       };
 
-
       /* At even X values we want the first 4 shorts, and at odd X values we
        * want the second 4 shorts.
        */
@@ -65,18 +73,16 @@ read_ds_quad(tile_t *buffer, unsigned x, unsigned y,
       break;
    }
 
-
    case PIPE_FORMAT_Z32_UNORM: {
-      qword *ptr = (qword *) &buffer->ui4[iy][ix];
+      qword *ptr = (qword *) &tile->ui4[iy][ix];
 
       *depth = *ptr;
       *stencil = si_il(0);
       break;
    }
-      
 
    case PIPE_FORMAT_Z24S8_UNORM: {
-      qword *ptr = (qword *) &buffer->ui4[iy][ix];
+      qword *ptr = (qword *) &tile->ui4[iy][ix];
       qword mask = si_fsmbi(0xEEEE);
 
       *depth = si_rotmai(si_and(*ptr, mask), -8);
@@ -84,16 +90,14 @@ read_ds_quad(tile_t *buffer, unsigned x, unsigned y,
       break;
    }
 
-
    case PIPE_FORMAT_S8Z24_UNORM: {
-      qword *ptr = (qword *) &buffer->ui4[iy][ix];
+      qword *ptr = (qword *) &tile->ui4[iy][ix];
 
       *depth = si_and(*ptr, si_fsmbi(0x7777));
       *stencil = si_andi(si_roti(*ptr, 8), 0x0ff);
       break;
    }
 
-
    default:
       ASSERT(0);
       break;
@@ -101,6 +105,14 @@ read_ds_quad(tile_t *buffer, unsigned x, unsigned y,
 }
 
 
+/**
+ * Put a quad of Z/stencil values into a tile.
+ * \param tile  the tile of Z/stencil values to write into
+ * \param x, y  location of the quad in the tile, in pixels
+ * \param depth_format  format of the tile's data
+ * \param detph  depth values to store
+ * \param stencil  stencil values to store
+ */
 static void
 write_ds_quad(tile_t *buffer, unsigned x, unsigned y,
               enum pipe_format depth_format,
@@ -124,14 +136,12 @@ write_ds_quad(tile_t *buffer, unsigned x, unsigned y,
       break;
    }
 
-
    case PIPE_FORMAT_Z32_UNORM: {
       qword *ptr = (qword *) &buffer->ui4[iy][ix];
       *ptr = depth;
       break;
    }
 
-
    case PIPE_FORMAT_Z24S8_UNORM: {
       qword *ptr = (qword *) &buffer->ui4[iy][ix];
       qword mask = si_fsmbi(0xEEEE);
@@ -141,7 +151,6 @@ write_ds_quad(tile_t *buffer, unsigned x, unsigned y,
       break;
    }
 
-
    case PIPE_FORMAT_S8Z24_UNORM: {
       qword *ptr = (qword *) &buffer->ui4[iy][ix];
       qword mask = si_fsmbi(0x7777);
@@ -151,7 +160,6 @@ write_ds_quad(tile_t *buffer, unsigned x, unsigned y,
       break;
    }
 
-
    default:
       ASSERT(0);
       break;
@@ -159,6 +167,14 @@ write_ds_quad(tile_t *buffer, unsigned x, unsigned y,
 }
 
 
+/**
+ * Do depth/stencil/alpha test for a "quad" of 4 fragments.
+ * \param x,y  location of quad within tile
+ * \param frag_mask  indicates which fragments are "alive"
+ * \param frag_depth  four fragment depth values
+ * \param frag_alpha  four fragment alpha values
+ * \param facing  front/back facing for four fragments (1=front, 0=back)
+ */
 qword
 spu_do_depth_stencil(int x, int y,
                      qword frag_mask, qword frag_depth, qword frag_alpha,