[evaluator] implement modulo

Implement evaluation of the modulo operator.

Fixes: #18.

src/evaluate.c

@@ -1375,6 +1375,28 @@ static tree eval_div(tree t, int depth)
     return ret;
 }
 
+static tree eval_mod(tree t, int depth)
+{
+    tree left = __evaluate_1(tMOD_LHS(t), depth + 1);
+    tree right = __evaluate_1(tMOD_RHS(t), depth + 1);
+
+    tree ret = tree_make(T_INTEGER);
+    mpz_init(tINT_VAL(ret));
+
+    if (is_T_LIVE_VAR(left))
+        left = make_int_from_live_var(left);
+
+    if (is_T_LIVE_VAR(right))
+        right = make_int_from_live_var(right);
+
+    if (!(is_T_INTEGER(left) && is_T_INTEGER(right)))
+        eval_die(t, "Could not modulus to non integer type\n");
+
+    mpz_mod(tINT_VAL(ret), tINT_VAL(left), tINT_VAL(right));
+
+    return ret;
+}
+
 static tree eval_comma(tree t, int depth)
 {
     __evaluate_1(tCOMMA_LHS(t), depth + 1);
@@ -2408,6 +2430,7 @@ static tree __evaluate_1(tree t, int depth)
     case T_RSHIFT:     result = eval_rshift(t, depth + 1);     break;
     case T_MUL:        result = eval_mul(t, depth + 1);        break;
     case T_DIV:        result = eval_div(t, depth + 1);        break;
+    case T_MOD:        result = eval_mod(t, depth + 1);        break;
     case T_COMMA:      result = eval_comma(t, depth + 1);      break;
     case T_LT:         result = eval_lt(t, depth + 1);         break;
     case T_GT:         result = eval_gt(t, depth + 1);         break;

testsuite/.gitignore

@@ -56,5 +56,6 @@ for-loop-init-decl
 sizeof-deref
 break
 comma
+modulo
 
 *.trs

testsuite/Makefile.am

@@ -13,7 +13,7 @@ check_PROGRAMS = puts strcat pass_parameter_printf decl_with_assign	\
                  if_stmts eqneq union-struct casts shift loops negate	\
                  ior function_ptr_typedef array_ptr			\
                  struct_array_alignment iand factorial char-decl-and-assignment \
-                 for-loop-init-decl sizeof-deref break comma
+                 for-loop-init-decl sizeof-deref break comma modulo
 
 expect_scripts = fileio.exp strtok.exp decl.exp chars.exp infix.exp \
                  repl-interrupt.exp

testsuite/modulo.c

@@ -0,0 +1,11 @@
+int printf(const char *s, ...);
+
+int main()
+{
+    printf("%d\n",30 % 50);
+    printf("%d\n",2 % 27);
+    printf("%d\n",3 % 87);
+    printf("%d\n",9 % 18);
+    printf("%d\n",100 % 200);
+    printf("%d\n",1024 % 8190);
+}