i965/fs: Implement textureSize (TXS) on Gen5+.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/mesa/drivers/dri/i965/brw_defines.h

@@ -634,6 +634,7 @@ enum opcode {
    FS_OPCODE_TXB,
    FS_OPCODE_TXD,
    FS_OPCODE_TXL,
+   FS_OPCODE_TXS,
    FS_OPCODE_DISCARD,
    FS_OPCODE_SPILL,
    FS_OPCODE_UNSPILL,
@@ -781,6 +782,7 @@ enum opcode {
 #define GEN5_SAMPLER_MESSAGE_SAMPLE_DERIVS       4
 #define GEN5_SAMPLER_MESSAGE_SAMPLE_BIAS_COMPARE 5
 #define GEN5_SAMPLER_MESSAGE_SAMPLE_LOD_COMPARE  6
+#define GEN5_SAMPLER_MESSAGE_SAMPLE_RESINFO      10
 
 /* for GEN5 only */
 #define BRW_SAMPLER_SIMD_MODE_SIMD4X2                   0

src/mesa/drivers/dri/i965/brw_fs.cpp

@@ -157,6 +157,7 @@ fs_visitor::implied_mrf_writes(fs_inst *inst)
    case FS_OPCODE_TXB:
    case FS_OPCODE_TXD:
    case FS_OPCODE_TXL:
+   case FS_OPCODE_TXS:
       return 1;
    case FS_OPCODE_FB_WRITE:
       return 2;

src/mesa/drivers/dri/i965/brw_fs.h

@@ -291,7 +291,8 @@ public:
       return (opcode == FS_OPCODE_TEX ||
 	      opcode == FS_OPCODE_TXB ||
 	      opcode == FS_OPCODE_TXD ||
-	      opcode == FS_OPCODE_TXL);
+	      opcode == FS_OPCODE_TXL ||
+	      opcode == FS_OPCODE_TXS);
    }
 
    bool is_math()

src/mesa/drivers/dri/i965/brw_fs_emit.cpp

@@ -242,6 +242,9 @@ fs_visitor::generate_tex(fs_inst *inst, struct brw_reg dst, struct brw_reg src)
 	    msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LOD;
 	 }
 	 break;
+      case FS_OPCODE_TXS:
+	 msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_RESINFO;
+	 break;
       case FS_OPCODE_TXD:
 	 /* There is no sample_d_c message; comparisons are done manually */
 	 msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_DERIVS;
@@ -775,6 +778,7 @@ fs_visitor::generate_code()
       case FS_OPCODE_TXB:
       case FS_OPCODE_TXD:
       case FS_OPCODE_TXL:
+      case FS_OPCODE_TXS:
 	 generate_tex(inst, dst, src[0]);
 	 break;
       case FS_OPCODE_DISCARD:

src/mesa/drivers/dri/i965/brw_fs_visitor.cpp

@@ -751,6 +751,8 @@ fs_visitor::emit_texture_gen5(ir_texture *ir, fs_reg dst, fs_reg coordinate,
    int base_mrf = 2;
    int reg_width = c->dispatch_width / 8;
    bool header_present = false;
+   const int vector_elements =
+      ir->coordinate ? ir->coordinate->type->vector_elements : 0;
 
    if (ir->offset) {
       /* The offsets set up by the ir_texture visitor are in the
@@ -761,7 +763,7 @@ fs_visitor::emit_texture_gen5(ir_texture *ir, fs_reg dst, fs_reg coordinate,
       base_mrf--;
    }
 
-   for (int i = 0; i < ir->coordinate->type->vector_elements; i++) {
+   for (int i = 0; i < vector_elements; i++) {
       fs_inst *inst = emit(BRW_OPCODE_MOV,
 			   fs_reg(MRF, base_mrf + mlen + i * reg_width),
 			   coordinate);
@@ -769,7 +771,7 @@ fs_visitor::emit_texture_gen5(ir_texture *ir, fs_reg dst, fs_reg coordinate,
 	 inst->saturate = true;
       coordinate.reg_offset++;
    }
-   mlen += ir->coordinate->type->vector_elements * reg_width;
+   mlen += vector_elements * reg_width;
 
    if (ir->shadow_comparitor && ir->op != ir_txd) {
       mlen = MAX2(mlen, header_present + 4 * reg_width);
@@ -837,8 +839,14 @@ fs_visitor::emit_texture_gen5(ir_texture *ir, fs_reg dst, fs_reg coordinate,
       inst = emit(FS_OPCODE_TXD, dst);
       break;
    }
-   case ir_txf:
    case ir_txs:
+      this->result = reg_undef;
+      ir->lod_info.lod->accept(this);
+      emit(BRW_OPCODE_MOV, fs_reg(MRF, base_mrf + mlen, BRW_REGISTER_TYPE_UD), this->result);
+      mlen += reg_width;
+      inst = emit(FS_OPCODE_TXS, dst);
+      break;
+   case ir_txf:
       assert(!"GLSL 1.30 features unsupported");
       break;
    }
@@ -927,14 +935,19 @@ fs_visitor::emit_texture_gen7(ir_texture *ir, fs_reg dst, fs_reg coordinate,
       }
       break;
    }
-   case ir_txf:
    case ir_txs:
+      this->result = reg_undef;
+      ir->lod_info.lod->accept(this);
+      emit(BRW_OPCODE_MOV, fs_reg(MRF, base_mrf + mlen, BRW_REGISTER_TYPE_UD), this->result);
+      mlen += reg_width;
+      break;
+   case ir_txf:
       assert(!"GLSL 1.30 features unsupported");
       break;
    }
 
    /* Set up the coordinate (except for TXD where it was done earlier) */
-   if (ir->op != ir_txd) {
+   if (ir->op != ir_txd && ir->op != ir_txs) {
       for (int i = 0; i < ir->coordinate->type->vector_elements; i++) {
 	 fs_inst *inst = emit(BRW_OPCODE_MOV, fs_reg(MRF, base_mrf + mlen),
 			      coordinate);
@@ -953,7 +966,7 @@ fs_visitor::emit_texture_gen7(ir_texture *ir, fs_reg dst, fs_reg coordinate,
    case ir_txl: inst = emit(FS_OPCODE_TXL, dst); break;
    case ir_txd: inst = emit(FS_OPCODE_TXD, dst); break;
    case ir_txf: assert(!"TXF unsupported."); break;
-   case ir_txs: assert(!"TXS unsupported."); break;
+   case ir_txs: inst = emit(FS_OPCODE_TXS, dst); break;
    }
    inst->base_mrf = base_mrf;
    inst->mlen = mlen;
@@ -988,7 +1001,8 @@ fs_visitor::visit(ir_texture *ir)
    }
 
    this->result = reg_undef;
-   ir->coordinate->accept(this);
+   if (ir->coordinate)
+      ir->coordinate->accept(this);
    fs_reg coordinate = this->result;
 
    if (ir->offset != NULL) {

src/mesa/program/ir_to_mesa.cpp

@@ -2104,7 +2104,10 @@ ir_to_mesa_visitor::visit(ir_texture *ir)
    ir_to_mesa_instruction *inst = NULL;
    prog_opcode opcode = OPCODE_NOP;
 
-   ir->coordinate->accept(this);
+   if (ir->op == ir_txs)
+      this->result = src_reg_for_float(0.0);
+   else
+      ir->coordinate->accept(this);
 
    /* Put our coords in a temp.  We'll need to modify them for shadow,
     * projection, or LOD, so the only case we'd use it as is is if
@@ -2128,6 +2131,7 @@ ir_to_mesa_visitor::visit(ir_texture *ir)
 
    switch (ir->op) {
    case ir_tex:
+   case ir_txs:
       opcode = OPCODE_TEX;
       break;
    case ir_txb:
@@ -2148,7 +2152,6 @@ ir_to_mesa_visitor::visit(ir_texture *ir)
       dy = this->result;
       break;
    case ir_txf:
-   case ir_txs:
       assert(!"GLSL 1.30 features unsupported");
       break;
    }