From 8f95efc25785774788c8a434c33355c3dcc6a94e Mon Sep 17 00:00:00 2001
From: "R. Timothy Edwards" <tim@opencircuitdesign.com>
Date: Tue, 17 Mar 2026 11:32:53 -0400
Subject: [PATCH] Added a feature to the toolkit scripts for generated devices
 to allow ideal devices in an input netlist to be mapped to automatically
 generated cells.  This works if the PDK toolkit defines a device called
 either "capacitor" or "resistor".  The device must be defined such that it
 can determine sane parameters for the drawn device from only a value given in
 the netlist (capacitance in farads, or resistance in ohms).

---
 VERSION           |  2 +-
 tcltk/toolkit.tcl | 24 ++++++++++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/VERSION b/VERSION
index 22af1b01..a57ad58b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.3.623
+8.3.624
diff --git a/tcltk/toolkit.tcl b/tcltk/toolkit.tcl
index c8bf8777..c14d8579 100644
--- a/tcltk/toolkit.tcl
+++ b/tcltk/toolkit.tcl
@@ -12,6 +12,8 @@
 # Added spice-to-layout procedure
 # March 4, 2026
 # Changed to make use of new "units" command
+# March 26, 2026
+# Added behavior to handle ideal capacitor and resistor devices
 #--------------------------------------------------------------
 # Sets up the environment for a toolkit.  The toolkit must
 # supply a namespace that is the "library name".  For each
@@ -281,8 +283,12 @@ proc magic::generate_layout_add {subname subpins complist library} {
 	set paramlist {}
 
 	# NOTE:  This routine deals with subcircuit calls and devices
-	# with models.  It needs to determine when a device is instantiated
-	# without a model, and ignore such devices.
+	# with models.  There are two exceptions, for toolkits which
+	# wish to implement a way to generate unmodeled capacitors or
+	# resistors based on value;  for example, metal interdigitated
+	# capacitors.  For those exceptions, the device value is recast
+	# as a parameter called "value", and the device is given a model
+	# "capacitor" or "resistor", respectively.
 
 	# Parse SPICE line into pins, device name, and parameters.  Make
 	# sure parameters incorporate quoted expressions as {} or ''.
@@ -326,6 +332,20 @@ proc magic::generate_layout_add {subname subpins complist library} {
 	set devtype [lindex $pinlist end]
 	set pinlist [lrange $pinlist 0 end-1]
 
+	# Ideal device check:  "devtype" will start with a digit.
+	# The instname will begin with "c" or "r".
+
+	if {[regexp {^([0-9\.]+.*)} $devtype pval]} {
+	    set comptype [string tolower [string range $instname 0 0]]
+	    if {$comptype == "c"} {
+		lappend paramlist [list value $pval]
+		set devtype capacitor
+	    } elseif {$comptype == "r"} {
+		lappend paramlist [list value $pval]
+		set devtype resistor
+	    }
+	}
+
 	set mult 1
 	foreach param $paramlist {
 	    set parmname [lindex $param 0]