src/mesa/drivers/dri/i965/gen6_constant_state.c

   1 /*
   2  * Copyright © 2015 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include "brw_context.h"
  25 #include "brw_state.h"
  26 #include "brw_defines.h"
  27 #include "intel_batchbuffer.h"
  28 #include "program/prog_parameter.h"
  29
  30 /**
  31  * Creates a streamed BO containing the push constants for the VS or GS on
  32  * gen6+.
  33  *
  34  * Push constants are constant values (such as GLSL uniforms) that are
  35  * pre-loaded into a shader stage's register space at thread spawn time.
  36  *
  37  * Not all GLSL uniforms will be uploaded as push constants: The hardware has
  38  * a limitation of 32 or 64 EU registers (256 or 512 floats) per stage to be
  39  * uploaded as push constants, while GL 4.4 requires at least 1024 components
  40  * to be usable for the VS.  Plus, currently we always use pull constants
  41  * instead of push constants when doing variable-index array access.
  42  *
  43  * See brw_curbe.c for the equivalent gen4/5 code.
  44  */
  45 void
  46 gen6_upload_push_constants(struct brw_context *brw,
  47                            const struct gl_program *prog,
  48                            const struct brw_stage_prog_data *prog_data,
  49                            struct brw_stage_state *stage_state)
  50 {
  51    struct gl_context *ctx = &brw->ctx;
  52
  53    if (prog_data->nr_params == 0) {
  54       stage_state->push_const_size = 0;
  55    } else {
  56       /* Updates the ParamaterValues[i] pointers for all parameters of the
  57        * basic type of PROGRAM_STATE_VAR.
  58        */
  59       /* XXX: Should this happen somewhere before to get our state flag set? */
  60       if (prog)
  61          _mesa_load_state_parameters(ctx, prog->Parameters);
  62
  63       gl_constant_value *param;
  64       int i;
  65
  66       param = brw_state_batch(brw,
  67                               prog_data->nr_params * sizeof(gl_constant_value),
  68                               32, &stage_state->push_const_offset);
  69
  70       STATIC_ASSERT(sizeof(gl_constant_value) == sizeof(float));
  71
  72       /* _NEW_PROGRAM_CONSTANTS
  73        *
  74        * Also _NEW_TRANSFORM -- we may reference clip planes other than as a
  75        * side effect of dereferencing uniforms, so _NEW_PROGRAM_CONSTANTS
  76        * wouldn't be set for them.
  77        */
  78       for (i = 0; i < prog_data->nr_params; i++) {
  79          param[i] = *prog_data->param[i];
  80       }
  81
  82       if (0) {
  83          fprintf(stderr, "%s constants:\n",
  84                  _mesa_shader_stage_to_string(stage_state->stage));
  85          for (i = 0; i < prog_data->nr_params; i++) {
  86             if ((i & 7) == 0)
  87                fprintf(stderr, "g%d: ",
  88                        prog_data->dispatch_grf_start_reg + i / 8);
  89             fprintf(stderr, "%8f ", param[i].f);
  90             if ((i & 7) == 7)
  91                fprintf(stderr, "\n");
  92          }
  93          if ((i & 7) != 0)
  94             fprintf(stderr, "\n");
  95          fprintf(stderr, "\n");
  96       }
  97
  98       stage_state->push_const_size = ALIGN(prog_data->nr_params, 8) / 8;
  99       /* We can only push 32 registers of constants at a time. */
 100
 101       /* From the SNB PRM (vol2, part 1, section 3.2.1.4: 3DSTATE_CONSTANT_VS:
 102        *
 103        *     "The sum of all four read length fields (each incremented to
 104        *      represent the actual read length) must be less than or equal to
 105        *      32"
 106        *
 107        * From the IVB PRM (vol2, part 1, section 3.2.1.3: 3DSTATE_CONSTANT_VS:
 108        *
 109        *     "The sum of all four read length fields must be less than or
 110        *      equal to the size of 64"
 111        *
 112        * The other shader stages all match the VS's limits.
 113        */
 114       assert(stage_state->push_const_size <= 32);
 115    }
 116 }