scc

commit b180e15d2a5fb72ee3aa45a5cf6a3e27a016aed0
parent b584afc229761ee1e36f523ea33e717ea0ef2586
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Fri, 20 Mar 2015 11:48:38 -0400

Add initial support for return statements

This is only a stab, because it doesn't do anything with the
statement.

Diffstat:
M
cc2/cc2.h
 | 
1
+
M
cc2/cgen.c
 | 
8
+++++++-
M
cc2/parser.c
 | 
39
+++++++++++++++++++++++++++++++++------

3 files changed, 41 insertions(+), 7 deletions(-)
diff --git a/cc2/cc2.h b/cc2/cc2.h
@@ -36,6 +36,7 @@
 #define ONEG      '_'
 #define OCPL      '~'
 #define OCOMMA    ','
+#define ORET      'y'
 
 #define ADDABLE 10
 
diff --git a/cc2/cgen.c b/cc2/cgen.c
@@ -359,10 +359,16 @@ assign(Node *np)
 	np->reg = rp->reg;
 }
 
+static void
+ret(Node *np)
+{
+}
+
 static void (*opnodes[])(Node *) = {
 	[OADD] = add,
 	[OSUB] = add,
-	[OASSIG] = assign
+	[OASSIG] = assign,
+	[ORET] = ret
 };
 
 static void
diff --git a/cc2/parser.c b/cc2/parser.c
@@ -90,7 +90,7 @@ static Type l_uint64 = {
 
 static void cast(char *), operator(char *), assignment(char *), increment(char *),
             globvar(char *), localvar(char *), paramvar(char *), label(char *),
-            immediate(char *), unary(char *);
+            immediate(char *), unary(char *), oreturn(char *);
 
 /*TODO: Remove hardcoded symbols */
 
@@ -137,7 +137,7 @@ static void (*optbl[])(char *) = {
 	['['] = operator,
 	['='] = operator,
 	['!'] = unary,
-	['y'] = NULL,
+	['y'] = oreturn,
 	['j'] = NULL,
 	['o'] = operator,
 	['_'] = unary,
@@ -421,20 +421,30 @@ cast(char *token)
 }
 
 static void
-expression(char *token)
+expr(char *token)
 {
 	Node *np;
 	void (*fun)(char *);
 	unsigned c;
 
-	if (!curfun)
-		error(ESYNTAX);
-
 	do {
 		if ((c = token[0]) > 0x7f || (fun = optbl[c]) == NULL)
 			error(ESYNTAX);
 		(*fun)(token);
 	} while (token = strtok(NULL, "\t"));
+}
+
+static void
+expression(char *token)
+{
+	Node *np;
+	void (*fun)(char *);
+	unsigned c;
+
+	if (!curfun)
+		error(ESYNTAX);
+
+	expr(token);
 
 	np = pop();
 	if (stackp != stack)
@@ -445,6 +455,23 @@ expression(char *token)
 }
 
 static void
+oreturn(char *token)
+{
+	Node *np = newnode();
+
+	np->op = token[0];
+
+	if (token = strtok(NULL, "\t")) {
+		expr(token);
+		np -> left = pop();
+	} else {
+		np->left = NULL;
+	}
+	np->right = NULL;
+	push(np);
+}
+
+static void
 deflabel(char *token)
 {
 	Symbol *sym;