i965: Add SNB math opcode support.

This is untested at this point.

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

 #define BRW_OPCODE_POP        47
 #define BRW_OPCODE_WAIT       48
 #define BRW_OPCODE_SEND       49
+#define BRW_OPCODE_MATH       56
 #define BRW_OPCODE_ADD        64
 #define BRW_OPCODE_MUL        65
 #define BRW_OPCODE_AVG        66
 #define BRW_MATH_FUNCTION_SIN                              6 /* was 7 */
 #define BRW_MATH_FUNCTION_COS                              7 /* was 8 */
 #define BRW_MATH_FUNCTION_SINCOS                           8 /* was 6 */
-#define BRW_MATH_FUNCTION_TAN                              9
+#define BRW_MATH_FUNCTION_TAN                              9 /* gen4 */
+#define BRW_MATH_FUNCTION_FDIV                             9 /* gen6+ */
 #define BRW_MATH_FUNCTION_POW                              10
 #define BRW_MATH_FUNCTION_INT_DIV_QUOTIENT_AND_REMAINDER   11
 #define BRW_MATH_FUNCTION_INT_DIV_QUOTIENT                 12

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

 	       GLuint data_type,
 	       GLuint precision )
 {
-   struct brw_instruction *insn = next_insn(p, BRW_OPCODE_SEND);
-   GLuint msg_length = (function == BRW_MATH_FUNCTION_POW) ? 2 : 1; 
-   GLuint response_length = (function == BRW_MATH_FUNCTION_SINCOS) ? 2 : 1; 
+   struct intel_context *intel = &p->brw->intel;
 
-   /* Example code doesn't set predicate_control for send
-    * instructions.
-    */
-   insn->header.predicate_control = 0; 
-   insn->header.destreg__conditionalmod = msg_reg_nr;
+   if (intel->gen >= 6) {
+      struct brw_instruction *insn = next_insn(p, BRW_OPCODE_MATH);
 
-   brw_set_dest(insn, dest);
-   brw_set_src0(insn, src);
-   brw_set_math_message(p->brw,
-			insn, 
-			msg_length, response_length, 
-			function,
-			BRW_MATH_INTEGER_UNSIGNED,
-			precision,
-			saturate,
-			data_type);
+      /* Math is the same ISA format as other opcodes, except that CondModifier
+       * becomes FC[3:0] and ThreadCtrl becomes FC[5:4].
+       */
+      insn->header.destreg__conditionalmod = function;
+
+      brw_set_dest(insn, dest);
+      brw_set_src0(insn, src);
+      brw_set_src1(insn, brw_null_reg());
+   } else {
+      struct brw_instruction *insn = next_insn(p, BRW_OPCODE_SEND);
+      GLuint msg_length = (function == BRW_MATH_FUNCTION_POW) ? 2 : 1;
+      GLuint response_length = (function == BRW_MATH_FUNCTION_SINCOS) ? 2 : 1;
+      /* Example code doesn't set predicate_control for send
+       * instructions.
+       */
+      insn->header.predicate_control = 0;
+      insn->header.destreg__conditionalmod = msg_reg_nr;
+
+      brw_set_dest(insn, dest);
+      brw_set_src0(insn, src);
+      brw_set_math_message(p->brw,
+			   insn,
+			   msg_length, response_length,
+			   function,
+			   BRW_MATH_INTEGER_UNSIGNED,
+			   precision,
+			   saturate,
+			   data_type);
+   }
 }
 
 /**

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

     * whether that turns out to be a simulator bug or not:
     */
    struct brw_compile *p = &c->func;
+   struct intel_context *intel = &p->brw->intel;
    struct brw_reg tmp = dst;
-   GLboolean need_tmp = (dst.dw1.bits.writemask != 0xf ||
-			 dst.file != BRW_GENERAL_REGISTER_FILE);
+   GLboolean need_tmp = (intel->gen < 6 &&
+			 (dst.dw1.bits.writemask != 0xf ||
+			  dst.file != BRW_GENERAL_REGISTER_FILE));
 
    if (need_tmp) 
       tmp = get_tmp(c);
 			GLuint precision)
 {
    struct brw_compile *p = &c->func;
+   struct intel_context *intel = &p->brw->intel;
    struct brw_reg tmp = dst;
-   GLboolean need_tmp = (dst.dw1.bits.writemask != 0xf ||
-			 dst.file != BRW_GENERAL_REGISTER_FILE);
+   GLboolean need_tmp = (intel->gen < 6 &&
+			 (dst.dw1.bits.writemask != 0xf ||
+			  dst.file != BRW_GENERAL_REGISTER_FILE));
 
    if (need_tmp) 
       tmp = get_tmp(c);