Support declaration of ariables with an initialization value

1 files changed, 26 insertions, 2 deletions

diff --git a/pp2cc.py b/pp2cc.py
index 35b208b..224a88f 100755
--- a/pp2cc.py
+++ b/pp2cc.py
@@ -240,8 +240,12 @@ class Parse(object):
         }
         self.binary_ops.update(self.comparison_ops)
 
+        # global variable names to be defined in @DATA
         self.globalVars = []
         self.functions = {}
+        # holds instructions for initializing the globalVars
+        self.globalInit = []
+        # holds the miscellaneous instructions for @CODE
         self.codeSegment = []
         self.labels = set()
         # helper for asm code generation
@@ -285,9 +289,16 @@ class Parse(object):
             self.addSource(self.nameToVar(varName) + padding + " DW 1")
         self.addSource()
         self.addSource("@CODE")
-        for line in self.codeSegment:
+        # initialization of global variables
+        for line in self.globalInit:
             self.addSource(line)
+
+        if not "main" in self.functions:
+            self.logger.warning("No main function found with label 'fn_main'")
+        self.addSource(self.asm.branch_op("BRA", "fn_main"))
         self.addSource()
+        for line in self.codeSegment:
+            self.addSource(line)
         self.addSource()
         self.addSource("@END")
     def addSource(self, line=''):
@@ -808,11 +819,24 @@ class Parse(object):
             raise RuntimeError("Unsupported assignment operator: " + node.op)
         return lines
     def parseDecl(self, linked_node):
+        lines = []
         varname = linked_node.node.name
         if varname in self.globalVars:
             raise RuntimeError("Redefinition of variable '{}'".format(varname))
         self.globalVars.append(varname)
-        return []
+
+        # if the declaration also has a definition
+        if linked_node.node.init:
+            var_name = self.nameToVar(varname)
+            init_val = self.parseStatement(linked_node.node.init, linked_node)
+            result_reg = self.registers.find_register(init_val)
+            init_val.append(self.asm.binary_op("STOR", result_reg, "[GB+" + var_name + "]"))
+            # if global context (i.e. not in a function)
+            if linked_node.getFunctionNode() is None:
+                self.globalInit += init_val
+            else:
+                lines += init_val
+        return lines
     def parseStatement(self, node, parent_linked_node, level_increment=False):
         linked_node = LinkedNode(node, parent_linked_node, level_increment=level_increment)
         self.asm.level = linked_node.level