Mesa (master): i965: Add support for gen6 CONTINUE instruction emit.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 843a6a308e05bd4bf2056e08ec65ac4770097b93
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=843a6a308e05bd4bf2056e08ec65ac4770097b93

Author: Eric Anholt <eric at anholt.net>
Date:   Wed Dec  1 14:02:14 2010 -0800

i965: Add support for gen6 CONTINUE instruction emit.

At this point, piglit tests for fragment shader loops are working.

---

 src/mesa/drivers/dri/i965/brw_eu.h      |    2 ++
 src/mesa/drivers/dri/i965/brw_eu_emit.c |   24 +++++++++++++++++++++++-
 src/mesa/drivers/dri/i965/brw_fs.cpp    |    6 +++---
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_eu.h b/src/mesa/drivers/dri/i965/brw_eu.h
index df5ce56..a4904b7 100644
--- a/src/mesa/drivers/dri/i965/brw_eu.h
+++ b/src/mesa/drivers/dri/i965/brw_eu.h
@@ -954,6 +954,8 @@ struct brw_instruction *brw_WHILE(struct brw_compile *p,
 	       struct brw_instruction *patch_insn);
 
 struct brw_instruction *brw_BREAK(struct brw_compile *p, int pop_count);
+struct brw_instruction *brw_CONT_gen6(struct brw_compile *p,
+				      struct brw_instruction *do_insn);
 struct brw_instruction *brw_CONT(struct brw_compile *p, int pop_count);
 /* Forward jumps:
  */
diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c
index 7eb7bdf..945f50d 100644
--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
@@ -1050,6 +1050,26 @@ struct brw_instruction *brw_BREAK(struct brw_compile *p, int pop_count)
    return insn;
 }
 
+struct brw_instruction *brw_CONT_gen6(struct brw_compile *p,
+				      struct brw_instruction *do_insn)
+{
+   struct brw_instruction *insn;
+   int br = 2;
+
+   insn = next_insn(p, BRW_OPCODE_CONTINUE);
+   brw_set_dest(insn, retype(brw_null_reg(), BRW_REGISTER_TYPE_D));
+   brw_set_src0(insn, retype(brw_null_reg(), BRW_REGISTER_TYPE_D));
+   brw_set_dest(insn, brw_ip_reg());
+   brw_set_src0(insn, brw_ip_reg());
+   brw_set_src1(insn, brw_imm_d(0x0));
+
+   insn->bits3.break_cont.uip = br * (do_insn - insn);
+
+   insn->header.compression_control = BRW_COMPRESSION_NONE;
+   insn->header.execution_size = BRW_EXECUTE_8;
+   return insn;
+}
+
 struct brw_instruction *brw_CONT(struct brw_compile *p, int pop_count)
 {
    struct brw_instruction *insn;
@@ -2087,7 +2107,9 @@ brw_set_uip_jip(struct brw_compile *p)
 	 /* JIP is set at CONTINUE emit time, since that's when we
 	  * know where the start of the loop is.
 	  */
-	 insn->bits3.break_cont.uip = br * (brw_find_next_block_end(p, ip) - ip);
+	 insn->bits3.break_cont.jip = br * (brw_find_next_block_end(p, ip) - ip);
+	 assert(insn->bits3.break_cont.uip != 0);
+	 assert(insn->bits3.break_cont.jip != 0);
 	 break;
       }
    }
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 46061c7..ee9ae16 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3390,9 +3390,9 @@ fs_visitor::generate_code()
       case BRW_OPCODE_CONTINUE:
 	 /* FINISHME: We need to write the loop instruction support still. */
 	 if (intel->gen >= 6)
-	    this->fail = true;
-
-	 brw_CONT(p, if_depth_in_loop[loop_stack_depth]);
+	    brw_CONT_gen6(p, loop_stack[loop_stack_depth - 1]);
+	 else
+	    brw_CONT(p, if_depth_in_loop[loop_stack_depth]);
 	 brw_set_predicate_control(p, BRW_PREDICATE_NONE);
 	 break;