[Mesa-dev] [PATCH v2 31/53] intel/compiler: set correct precision fields for 3-source float instructions

[Iago Toral Quiroga]

Source0 and Destination extract the floating-point precision automatically
from the SrcType and DstType instruction fields respectively when they are
set to types :F or :HF. For Source1 and Source2 operands, we use the new
1-bit fields Src1Type and Src2Type, where 0 means normal precision and 1
means half-precision. Since we always use the type of the destination for
all operands when we emit 3-source instructions, we only need set Src1Type
and Src2Type to 1 when we are emitting a half-precision instruction.

v2:
 - Set the bit separately for each source based on its type so we can
   do mixed floating-point mode in the future (Topi).

Reviewed-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
---
 src/intel/compiler/brw_eu_emit.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/intel/compiler/brw_eu_emit.c b/src/intel/compiler/brw_eu_emit.c
index 0f6498614e8..9232adcadc7 100644
--- a/src/intel/compiler/brw_eu_emit.c
+++ b/src/intel/compiler/brw_eu_emit.c
@@ -801,6 +801,22 @@ brw_alu3(struct brw_codegen *p, unsigned opcode, struct brw_reg dest,
           */
          brw_inst_set_3src_a16_src_type(devinfo, inst, dest.type);
          brw_inst_set_3src_a16_dst_type(devinfo, inst, dest.type);
+
+         /* From the Bspec: Instruction types
+          *
+          * Three source instructions can use operands with mixed-mode
+          * precision. When SrcType field is set to :f or :hf it defines
+          * precision for source 0 only, and fields Src1Type and Src2Type
+          * define precision for other source operands:
+          *
+          *   0b = :f. Single precision Float (32-bit).
+          *   1b = :hf. Half precision Float (16-bit).
+          */
+         if (src1.type == BRW_REGISTER_TYPE_HF)
+            brw_inst_set_3src_a16_src1_type(devinfo, inst, 1);
+
+         if (src2.type == BRW_REGISTER_TYPE_HF)
+            brw_inst_set_3src_a16_src2_type(devinfo, inst, 1);
       }
    }
 
-- 
2.17.1