Merge pull request The-OpenROAD-Project#3270 from Pinata-Consulting/variables-better-docs-simpler-tcl

variables: move default value into variables.yaml

Author: maliberty

docs/user/FlowVariables.md

@@ -107,8 +107,8 @@ configuration file.
 | <a name="CELL_PAD_IN_SITES_GLOBAL_PLACEMENT"></a>CELL_PAD_IN_SITES_GLOBAL_PLACEMENT| Cell padding on both sides in site widths to ease routability during global placement.| 0| |
 | <a name="CLKGATE_MAP_FILE"></a>CLKGATE_MAP_FILE| List of cells for gating clock treated as a black box by Yosys.| | |
 | <a name="CORE_AREA"></a>CORE_AREA| The core area specified as a list of lower-left and upper-right corners in microns (X1 Y1 X2 Y2).| | |
-| <a name="CORE_ASPECT_RATIO"></a>CORE_ASPECT_RATIO| The core aspect ratio (height / width). This value is ignored if `CORE_UTILIZATION` is undefined.| | |
-| <a name="CORE_MARGIN"></a>CORE_MARGIN| The margin between the core area and die area, specified in microns. Allowed values are either one value for all margins or a set of four values, one for each margin. The order of the four values are: `{bottom top left right}`. This variable is ignored if `CORE_UTILIZATION` is undefined.| | |
+| <a name="CORE_ASPECT_RATIO"></a>CORE_ASPECT_RATIO| The core aspect ratio (height / width). This value is ignored if `CORE_UTILIZATION` is undefined.| 1.0| |
+| <a name="CORE_MARGIN"></a>CORE_MARGIN| The margin between the core area and die area, specified in microns. Allowed values are either one value for all margins or a set of four values, one for each margin. The order of the four values are: `{bottom top left right}`. This variable is ignored if `CORE_UTILIZATION` is undefined.| 1.0| |
 | <a name="CORE_UTILIZATION"></a>CORE_UTILIZATION| The core utilization percentage (0-100).| | |
 | <a name="CORNER"></a>CORNER| PVT corner library selection. Only available for ASAP7 and GF180 PDKs.| | |
 | <a name="CTS_ARGS"></a>CTS_ARGS| Override `clock_tree_synthesis` arguments.| | |

flow/scripts/floorplan.tcl

@@ -73,17 +73,9 @@ if {$use_floorplan_def} {
                          -site $::env(PLACE_SITE) \
                          {*}$additional_args
 } elseif {$use_core_utilization} {
-    set aspect_ratio 1.0
-    if {[env_var_exists_and_non_empty "CORE_ASPECT_RATIO"]} {
-        set aspect_ratio $::env(CORE_ASPECT_RATIO)
-    }
-    set core_margin 1.0
-    if {[env_var_exists_and_non_empty "CORE_MARGIN"]} {
-        set core_margin $::env(CORE_MARGIN)
-    }
     initialize_floorplan -utilization $::env(CORE_UTILIZATION) \
-                         -aspect_ratio $aspect_ratio \
-                         -core_space $core_margin \
+                         -aspect_ratio $::env(CORE_ASPECT_RATIO) \
+                         -core_space $::env(CORE_MARGIN) \
                          -site $::env(PLACE_SITE) \
                          {*}$additional_args
 } else {

flow/scripts/variables.yaml

@@ -695,6 +695,7 @@ CORE_ASPECT_RATIO:
     `CORE_UTILIZATION` is undefined.
   stages:
     - floorplan
+  default: 1.0
   tunable: 1
 CORE_MARGIN:
   description: >
@@ -705,6 +706,7 @@ CORE_MARGIN:
     is undefined.
   stages:
     - floorplan
+  default: 1.0
   tunable: 1
 DIE_AREA:
   description: >