diff --git a/src/compiler/nir/nir_intrinsics.py b/src/compiler/nir/nir_intrinsics.py
index a1a201fca00..8041adc25d8 100644
--- a/src/compiler/nir/nir_intrinsics.py
+++ b/src/compiler/nir/nir_intrinsics.py
@@ -1119,6 +1119,9 @@ system_value("tcs_out_param_base_r600", 4)
 system_value("tcs_rel_patch_id_r600", 1)
 system_value("tcs_tess_factor_base_r600", 1)
 
+# the tess coords come as xy only, z has to be calculated
+system_value("tess_coord_r600", 2)
+
 # load as many components as needed giving per-component addresses
 intrinsic("load_local_shared_r600", src_comp=[0], dest_comp=0, indices = [], flags = [CAN_ELIMINATE])