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).
v3:
- Use regular citation style for the comment referencing the PRM (Matt).
- Decided not to add asserts in the emission code to check that only
mixed HF/F types are used since such checks would break negative tests
for brw_eu_validate.c (Matt)
Reviewed-by: Topi Pohjolainen <topi.pohjolai...@intel.com>
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
Reviewed-by: Matt Turner <matts...@gmail.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 30037e71b00..195c26ab760 100644
--- a/src/intel/compiler/brw_eu_emit.c
+++ b/src/intel/compiler/brw_eu_emit.c
@@ -843,6 +843,22 @@ 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, 3D Media GPGPU, Instruction fields, srcType:
+ *
+ * "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
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