i965: implement relative addressing for VS constant buffer reads

A scatter-read should be possible, but we're just using two READs for
the time being.

1 files changed, 55 insertions, 4 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c
index c731a93a8d..df2141660c 100644
--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
@@ -1003,15 +1003,18 @@ void brw_dp_READ_4( struct brw_compile *p,
 
 
 /**
- * Read float[4] constant from VS constant buffer.
+ * Read float[4] constant(s) from VS constant buffer.
+ * For relative addressing, two float[4] constants will be read into 'dest'.
+ * Otherwise, one float[4] constant will be read into the lower half of 'dest'.
  */
 void brw_dp_READ_4_vs(struct brw_compile *p,
                       struct brw_reg dest,
                       GLboolean relAddr,
+                      struct brw_reg addrReg,
                       GLuint location,
                       GLuint bind_table_index)
 {
-   const GLuint msg_reg_nr = 1;
+   GLuint msg_reg_nr = 1;
 
    /*
    printf("vs const read msg, location %u, msg_reg_nr %d\n",
@@ -1034,7 +1037,12 @@ void brw_dp_READ_4_vs(struct brw_compile *p,
       b = brw_message_reg(msg_reg_nr);
       b = retype(b, BRW_REGISTER_TYPE_UD);
       /*b = get_element_ud(b, 2);*/
-      brw_MOV(p, b, brw_imm_ud(location));
+      if (relAddr) {
+         brw_ADD(p, b, addrReg, brw_imm_ud(location));
+      }
+      else {
+         brw_MOV(p, b, brw_imm_ud(location));
+      }
 
       brw_pop_insn_state(p);
    }
@@ -1053,13 +1061,56 @@ void brw_dp_READ_4_vs(struct brw_compile *p,
 
       brw_set_dp_read_message(insn,
 			      bind_table_index,
-			      0,  /* msg_control (0 means 1 Oword) */
+			      0,  /* msg_control (0 means 1 Oword, lower half) */
 			      BRW_DATAPORT_READ_MESSAGE_OWORD_BLOCK_READ, /* msg_type */
 			      0, /* source cache = data cache */
 			      1, /* msg_length */
 			      1, /* response_length (1 Oword) */
 			      0); /* eot */
    }
+
+   if (relAddr) {
+      /* second read to get second constant */
+      msg_reg_nr++;
+      {
+         /* Setup MRF[1] with location/offset into const buffer */
+         struct brw_reg b;
+
+         brw_push_insn_state(p);
+         brw_set_compression_control(p, BRW_COMPRESSION_NONE);
+         brw_set_mask_control(p, BRW_MASK_DISABLE);
+         brw_set_predicate_control(p, BRW_PREDICATE_NONE);
+
+         b = brw_message_reg(msg_reg_nr);
+         b = retype(b, BRW_REGISTER_TYPE_UD);
+         addrReg = suboffset(addrReg, 1); /* upper half of addrReg */
+         brw_ADD(p, b, addrReg, brw_imm_ud(location));
+
+         brw_pop_insn_state(p);
+      }
+
+      {
+         struct brw_instruction *insn = next_insn(p, BRW_OPCODE_SEND);
+
+         insn->header.predicate_control = BRW_PREDICATE_NONE;
+         insn->header.compression_control = BRW_COMPRESSION_NONE; 
+         insn->header.destreg__conditonalmod = msg_reg_nr;
+         insn->header.mask_control = BRW_MASK_DISABLE;
+         /*insn->header.access_mode = BRW_ALIGN_16;*/
+
+         brw_set_dest(insn, dest);
+         brw_set_src0(insn, brw_null_reg());
+
+         brw_set_dp_read_message(insn,
+                                 bind_table_index,
+                                 1,  /* msg_control (1 means 1 Oword, upper half) */
+                                 BRW_DATAPORT_READ_MESSAGE_OWORD_BLOCK_READ, /* msg_type */
+                                 0, /* source cache = data cache */
+                                 1, /* msg_length */
+                                 1, /* response_length (1 Oword) */
+                                 0); /* eot */
+      }
+   }
 }