shithub: scc

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Add initial support for return statements

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

--- a/cc2/cc2.h

+++ b/cc2/cc2.h

@@ -36,6 +36,7 @@

 #define ONEG      '_'

 #define OCPL      '~'

 #define OCOMMA    ','

+#define ORET      'y'

 #define ADDABLE 10

--- a/cc2/cgen.c

+++ b/cc2/cgen.c

@@ -359,10 +359,16 @@

 	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

--- a/cc2/parser.c

+++ b/cc2/parser.c

@@ -90,7 +90,7 @@

 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 @@

 	['['] = operator,

 	['='] = operator,

 	['!'] = unary,

-	['y'] = NULL,

+	['y'] = oreturn,

 	['j'] = NULL,

 	['o'] = operator,

 	['_'] = unary,

@@ -421,21 +421,31 @@

 }

 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)

 		error(EEXPBAL);

@@ -442,6 +452,23 @@

 	if (listp == &listexp[NR_EXPRESSIONS])

 		error(EEXPROV);

 	*listp++ = np;

+}

+

+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