feat: display bitmapword as bitmask, not integer

'bitmapword' is actually not just integer, but bitmask. Also, when
displaying pad length to nearest power of 2, so it's easier to compare
multiple bitmapwords together

Author: ashenBlade

src/variables.ts

@@ -696,18 +696,23 @@ export abstract class Variable {
         };
 
         const realType = Variable.getRealType(debugVariable, context);
-        if (context.debug.isValueStruct(debugVariable, realType) ||      /* Raw struct, i.e. allocated on stack */
-            !context.debug.isValidPointerType(debugVariable)) {             /* NULL */
+        if (context.debug.isValueStruct(debugVariable, realType) ||
+            !context.debug.isValidPointerType(debugVariable)) {
             if (context.debug.isNull(debugVariable) && 
                 debugVariable.type.endsWith('List *')) {
                 /* 
                  * Empty List is NIL == NULL == '0x0'
                  *
-                 * Also 'endsWith' checks for 'const List *'
+                 * Also 'endsWith' covers cases like 'const List *'
                  */
                 return new ListNodeVariable('List', args);
             }
 
+            if (realType === 'bitmapword') {
+                /* Show bitmapword as bitmask, not integer */
+                return new BitmapwordVariable(args);
+            }
+
             return new RealVariable(args);
         }
 
@@ -4137,6 +4142,33 @@ class BitmapSetSpecialMember extends NodeVariable {
     }
 }
 
+/**
+ * Represent single 'bitmapword' as bitmask, not integer
+ */
+class BitmapwordVariable extends RealVariable {
+    async getTreeItem(): Promise<vscode.TreeItem> {
+        const value = Number(this.value);
+        if (Number.isNaN(value)) {
+            return await super.getTreeItem();
+        }
+
+        let bitmask = value.toString(2);
+
+        /* 
+         * Pad length to nearest power of 2, so it is easier to compare
+         * multiple bitmapwords lying together.
+         */
+        const length = Math.pow(2, Math.ceil(Math.log2(bitmask.length)))
+        bitmask = bitmask.padStart(length, '0');
+
+        return {
+            label: `${this.name}: bitmapword`,
+            description: bitmask,
+            collapsibleState: vscode.TreeItemCollapsibleState.None
+        }
+    }
+}
+
 /**
  * Represents Integer, String, Boolean, Float or BitString nodes.
  * In older systems there was single 'Value' struct for them,