diff --git a/docs/linuxcnc-porting.md b/docs/linuxcnc-porting.md
index 091dff0..0abdeef 100644
--- a/docs/linuxcnc-porting.md
+++ b/docs/linuxcnc-porting.md
@@ -205,7 +205,7 @@ This matrix tracks LinuxCNC feature coverage for the web/WASM simulator. A featu
 | Digital/analog I/O `M62`-`M68` | covered with Canon digital output, analog output, and input wait callbacks preserved as temporary state events | `tests/gcode/linuxcnc_io_controls.ngc` |
 | Override controls `M48`-`M53` | covered with Canon feed override, spindle speed override, adaptive feed, and feed hold callbacks preserved as temporary state events | `tests/gcode/linuxcnc_override_controls.ngc` |
 | Modal state save/restore `M70`-`M73` | covered for main-program save/invalidate/restore plus O-word subroutine autorestore in smoke parser, with native/source regressions checking restored distance mode, units, and XY plane motion | `tests/gcode/linuxcnc_modal_state.ngc`, `tests/gcode/linuxcnc_modal_autorestore.ngc` |
-| LinuxCNC read-only named parameters | partially covered in smoke parser for common modal state reads used by O-word macros; `#<_lathe_diameter_mode>` and `#<_lathe_radius_mode>` are now covered through LinuxCNC native/source backends | `tests/gcode/linuxcnc_lathe_diameter_mode.ngc`, smoke API regression |
+| LinuxCNC read-only named parameters | common modal/unit/feed/spindle reads are covered through LinuxCNC native/source backends, with additional ccomp/spindle-mode readonly reads source-linked | `tests/gcode/linuxcnc_readonly_named_parameters.ngc`, `tests/gcode/linuxcnc_readonly_named_parameters_extra.ngc`, `tests/gcode/linuxcnc_lathe_diameter_mode.ngc` |
 | Feed and motion control modes `G93/G94/G95`, `G61/G61.1/G64` | covered through LinuxCNC native/source backends | `tests/gcode/linuxcnc_feed_modes.ngc`, `tests/gcode/linuxcnc_motion_modes.ngc` |
 | Canned cycle `G81/G80` | covered for drilling expand-to-canon path, including `G18/G19` plane-specific depth-axis mapping for representative drilling/boring cycles | `tests/gcode/linuxcnc_canned_cycle.ngc`, `tests/gcode/linuxcnc_canned_cycle_planes.ngc` |
 | Coordinate offset Canon events `G10 L2`, `G10 L20`, `G10 P0 active-system targeting`, `G54`-`G59.3` selection, `G52`, `G92/G92.1/G92.2/G92.3` | covered through LinuxCNC native/source backends, including all nine G5X indices | `tests/gcode/linuxcnc_coordinate_offsets.ngc`, `tests/gcode/linuxcnc_coordinate_l20.ngc`, `tests/gcode/linuxcnc_coordinate_p0.ngc`, `tests/gcode/linuxcnc_coordinate_select_all.ngc`, `tests/gcode/linuxcnc_g92_restore.ngc`, `tests/gcode/linuxcnc_g52_offset.ngc` |
diff --git a/test-all-native.sh b/test-all-native.sh
index e1a6788..f8b3534 100755
--- a/test-all-native.sh
+++ b/test-all-native.sh
@@ -559,6 +559,7 @@ fi
 grep -F 'convert_lathe_diameter_mode() scales G7/G8 X words and G76 I/J/K words' test-native.sh >/dev/null
 grep -F 'tests/gcode/linuxcnc_lathe_diameter_mode.ngc' test-native.sh >/dev/null
 grep -F 'tests/gcode/linuxcnc_lathe_diameter_g76.ngc' test-native.sh >/dev/null
+grep -F 'tests/gcode/linuxcnc_readonly_named_parameters.ngc' test-native.sh >/dev/null
 
 for script in \
     test-native.sh \
diff --git a/test-linuxcnc-rs274-native.sh b/test-linuxcnc-rs274-native.sh
index 20315b6..0e4dc2c 100755
--- a/test-linuxcnc-rs274-native.sh
+++ b/test-linuxcnc-rs274-native.sh
@@ -171,6 +171,9 @@ CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" "$build_dir/linuxcnc_rs2
 CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" "$build_dir/linuxcnc_rs274_dump" tests/gcode/linuxcnc_indexed_parameters.ngc >"$output_dir/cnc_sim_linuxcnc_indexed_parameters.json"
 CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" "$build_dir/linuxcnc_rs274_dump" tests/gcode/linuxcnc_named_parameter_normalization.ngc >"$output_dir/cnc_sim_linuxcnc_named_parameter_normalization.json"
 INI_FILE_NAME="$ini_named_parameter_file" CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" "$build_dir/linuxcnc_rs274_dump" tests/gcode/linuxcnc_ini_named_parameter.ngc >"$output_dir/cnc_sim_linuxcnc_ini_named_parameter.json"
+# Source basis: LinuxCNC src/emc/rs274ngc/interp_namedparams.cc lookup_named_param()
+# and init_readonly_param() expose modal/unit/feed/spindle readonly parameters.
+CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" "$build_dir/linuxcnc_rs274_dump" tests/gcode/linuxcnc_readonly_named_parameters.ngc >"$output_dir/cnc_sim_linuxcnc_readonly_named_parameters.json"
 cp "$base_var_file" "$var_file"
 CNC_SIM_RS274_VAR="$var_file" "$build_dir/linuxcnc_rs274_dump" tests/gcode/linuxcnc_coordinate_offsets.ngc >"$output_dir/cnc_sim_linuxcnc_coordinate_offsets.json"
 cp "$base_var_file" "$var_file"
@@ -1101,6 +1104,23 @@ expected_ini_named_moves = [(3, 3.25, 0), (5, 3.25, 1)]
 if ini_named_moves != expected_ini_named_moves:
     raise SystemExit(f"unexpected LinuxCNC INI named parameter motions: {ini_named_moves!r}")
 
+readonly_named = load("cnc_sim_linuxcnc_readonly_named_parameters.json")
+readonly_moves = [
+    (event["line"], event["end"]["x"], event["end"]["y"], event["end"]["z"])
+    for event in readonly_named
+    if event["type"] == "linear-feed"
+]
+expected_readonly_moves = [
+    (4, 1, 0, 0),
+    (8, 0.0393701, 1, 0),
+    (12, 1, 25.4, 1),
+    (16, 2, 25.4, 1),
+    (22, 2, 3, 1),
+    (25, 2, 3, 2),
+]
+if readonly_moves != expected_readonly_moves:
+    raise SystemExit(f"unexpected LinuxCNC readonly named parameter motions: {readonly_moves!r}")
+
 coords = load("cnc_sim_linuxcnc_coordinate_offsets.json")
 g5x = [event for event in coords if event["type"] == "set-g5x-offset"]
 g92 = [event for event in coords if event["type"] == "set-g92-offset"]
@@ -1251,6 +1271,7 @@ echo "dumped $output_dir/cnc_sim_linuxcnc_named_parameter_exists.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_indexed_parameters.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_named_parameter_normalization.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_ini_named_parameter.json"
+echo "dumped $output_dir/cnc_sim_linuxcnc_readonly_named_parameters.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_coordinate_offsets.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_coordinate_l20.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_coordinate_p0.json"
diff --git a/test-linuxcnc-source-link.sh b/test-linuxcnc-source-link.sh
index fdb7db0..50f5a7d 100755
--- a/test-linuxcnc-source-link.sh
+++ b/test-linuxcnc-source-link.sh
@@ -545,6 +545,11 @@ CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" \
 INI_FILE_NAME="$ini_named_parameter_file" CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" \
     "$build_dir/linuxcnc_rs274_source_dump" tests/gcode/linuxcnc_ini_named_parameter.ngc \
     >"$output_dir/cnc_sim_linuxcnc_source_ini_named_parameter.json"
+# Source basis: LinuxCNC src/emc/rs274ngc/interp_namedparams.cc lookup_named_param()
+# and init_readonly_param() expose modal/unit/feed/spindle readonly parameters.
+CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" \
+    "$build_dir/linuxcnc_rs274_source_dump" tests/gcode/linuxcnc_readonly_named_parameters.ngc \
+    >"$output_dir/cnc_sim_linuxcnc_source_readonly_named_parameters.json"
 CNC_SIM_RS274_FILE_MODE=1 CNC_SIM_RS274_VAR="$var_file" \
     "$build_dir/linuxcnc_rs274_source_dump" tests/gcode/linuxcnc_readonly_named_parameters_extra.ngc \
     >"$output_dir/cnc_sim_linuxcnc_source_readonly_named_parameters_extra.json"
@@ -1826,6 +1831,23 @@ expected_ini_named_moves = [(3, 3.25, 0), (5, 3.25, 1)]
 if ini_named_moves != expected_ini_named_moves:
     raise SystemExit(f"unexpected source-linked INI named parameter motions: {ini_named_moves!r}")
 
+readonly_common = json.loads((OUTPUT_DIR / "cnc_sim_linuxcnc_source_readonly_named_parameters.json").read_text())
+readonly_common_moves = [
+    (event["line"], event["end"]["x"], event["end"]["y"], event["end"]["z"])
+    for event in readonly_common
+    if event["type"] == "linear-feed"
+]
+expected_readonly_common_moves = [
+    (4, 1, 0, 0),
+    (8, 0.0393701, 1, 0),
+    (12, 1, 25.4, 1),
+    (16, 2, 25.4, 1),
+    (22, 2, 3, 1),
+    (25, 2, 3, 2),
+]
+if readonly_common_moves != expected_readonly_common_moves:
+    raise SystemExit(f"unexpected source-linked readonly named parameter motions: {readonly_common_moves!r}")
+
 readonly_named = json.loads((OUTPUT_DIR / "cnc_sim_linuxcnc_source_readonly_named_parameters_extra.json").read_text())
 if not any(
     event["type"] == "linear-feed" and
@@ -2539,6 +2561,7 @@ echo "dumped $output_dir/cnc_sim_linuxcnc_source_named_parameter_exists.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_indexed_parameters.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_named_parameter_normalization.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_ini_named_parameter.json"
+echo "dumped $output_dir/cnc_sim_linuxcnc_source_readonly_named_parameters.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_readonly_named_parameters_extra.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_value_returned.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_call_level.json"
diff --git a/test-native.sh b/test-native.sh
index d473510..c01e1da 100755
--- a/test-native.sh
+++ b/test-native.sh
@@ -145,6 +145,8 @@ grep -F 'convert_lathe_diameter_mode() scales G7/G8 X words and G76 I/J/K words'
 grep -F 'tests/gcode/linuxcnc_lathe_diameter_mode.ngc' docs/linuxcnc-porting.md >/dev/null
 grep -F 'tests/gcode/linuxcnc_lathe_diameter_g76.ngc' docs/linuxcnc-porting.md >/dev/null
 grep -F 'missing source-linked G7 diameter-mode G76 final threading pass' test-linuxcnc-source-link.sh >/dev/null
+grep -F 'lookup_named_param()' test-linuxcnc-rs274-native.sh >/dev/null
+grep -F 'tests/gcode/linuxcnc_readonly_named_parameters.ngc' docs/linuxcnc-porting.md >/dev/null
 grep -F 'rs274ngc_pre.cc ini_load() consumes INI_FILE_NAME' test-web-wasm-node-smoke.cjs >/dev/null
 grep -F 'rs274ngc_pre.cc ini_load() consumes INI_FILE_NAME' web/test-browser-wasm-smoke-linuxcnc-sections.js >/dev/null
 grep -F 'metadata:src/emc/nml_intf/emcops.cc:source basis for native source-link EMC status constructor support object' linuxcnc-rs274-source-files.txt >/dev/null
diff --git a/tests/gcode/linuxcnc_readonly_named_parameters.ngc b/tests/gcode/linuxcnc_readonly_named_parameters.ngc
new file mode 100644
index 0000000..904d977
--- /dev/null
+++ b/tests/gcode/linuxcnc_readonly_named_parameters.ngc
@@ -0,0 +1,27 @@
+G21 G90 G17
+F100
+O10 if [#<_metric> EQ 1]
+G1 X1
+O10 endif
+G20
+O20 if [#<_imperial> EQ 1]
+G1 Y1
+O20 endif
+G21
+O30 if [#<_absolute> EQ 1]
+G1 Z1
+O30 endif
+G91
+O40 if [#<_incremental> EQ 1]
+G1 X1
+O40 endif
+G90
+F123
+S456 M3
+O50 if [[#<_feed> EQ 123] AND [#<_rpm> EQ 456]]
+G1 Y3
+O50 endif
+O60 if [[#<_spindle_on> EQ 1] AND [#<_spindle_cw> EQ 1]]
+G1 Z2
+O60 endif
+M30