issue #114 experiment with for loop

src/ravi_jitshared.c

@@ -1611,6 +1611,31 @@ static void emit_op_iforprep(struct function *fn, int A, int pc, int step_one, i
   membuff_add_fstring(&fn->body, "goto Lbc_%d;\n", pc);
 }
 
+static void emit_op_forprep_int(struct function *fn, int A, int pc, int pc1) {
+    (void)pc1;
+    if (!fn->locals[A]) {
+        fn->locals[A] = 1;  // Lua can reuse the same forloop vars if loop isn't nested
+        membuff_add_fstring(&fn->prologue, "lua_Integer i_%d = 0;\n", A);
+        membuff_add_fstring(&fn->prologue, "lua_Integer limit_%d = 0;\n", A);
+        membuff_add_fstring(&fn->prologue, "lua_Integer step_%d = 0;\n", A);
+    }
+    emit_reg(fn, "ra", A);  // init
+    membuff_add_string(&fn->body, "rb = ra+1; /*limit*/\n");
+    membuff_add_string(&fn->body, "rc = ra+2; /*step*/\n");
+    membuff_add_fstring(
+            &fn->body, "if (ttisinteger(ra) && ttisinteger(rc) && ttisinteger(rb)) {\n", A);
+    membuff_add_fstring(&fn->body, " limit_%d = ivalue(rb);\n", A);
+    membuff_add_fstring(&fn->body, " i_%d = ivalue(ra);\n", A);
+    membuff_add_fstring(&fn->body, " step_%d = ivalue(rc);\n", A);
+    membuff_add_fstring(&fn->body, " i_%d -= step_%d;\n", A, A);
+    membuff_add_fstring(&fn->body, " goto Lbc_%d;\n", pc);
+    membuff_add_string(&fn->body, "}\n");
+    membuff_add_string(&fn->body, "else {\n");
+    membuff_add_fstring(&fn->body, " error_code = %d;\n", Error_for_limit_must_be_number);
+    membuff_add_string(&fn->body, " goto Lraise_error;\n");
+    membuff_add_string(&fn->body, "}\n");
+}
+
 static void emit_op_forprep(struct function *fn, int A, int pc, int pc1) {
   (void)pc1;
   if (!fn->locals[A]) {
@@ -1680,6 +1705,14 @@ static void emit_op_iforloop(struct function *fn, int A, int pc, int step_one, i
                       A, A, A + 3, A, pc);
 }
 
+static void emit_op_forloop_int(struct function *fn, int A, int pc, int pc1) {
+    (void)pc1;
+    membuff_add_fstring(&fn->body, "i_%d += step_%d;\n", A, A);
+    membuff_add_fstring(&fn->body, "if ((0 < step_%d) ? (i_%d <= limit_%d) : (limit_%d <= i_%d)) {\n", A, A, A, A, A);
+    membuff_add_fstring(&fn->body, " ra = R(%d);\n   setivalue(ra, i_%d);\n   goto Lbc_%d;\n", A + 3, A, pc);
+    membuff_add_string(&fn->body, "}\n");
+}
+
 static void emit_op_forloop(struct function *fn, int A, int pc, int pc1) {
   (void)pc1;
   membuff_add_fstring(&fn->body, "if (intloop_%d) {\n", A);