Method callFunction

src/chap13/StoneVM.java:133–152

()

        pc += 4;
    }
    protected void callFunction() {
        Object value = registers[decodeRegister(code[pc + 1])];
        int numOfArgs = code[pc + 2];
        if (value instanceof VmFunction
            && ((VmFunction)value).parameters().size() == numOfArgs) {
            ret = pc + 3;
            pc = ((VmFunction)value).entry();
        }
        else if (value instanceof NativeFunction
                && ((NativeFunction)value).numOfParameters() == numOfArgs) {
            Object[] args = new Object[numOfArgs];
            for (int i = 0; i < numOfArgs; i++)
                args[i] = stack[sp + i];
            stack[sp] = ((NativeFunction)value).invoke(args,
                                        new ASTList(new ArrayList<ASTree>()));
            pc += 3;
        }
        else
            throw new StoneException("bad function call");
    }
    protected void saveRegisters() {
        int size = decodeOffset(code[pc + 1]);
        int dest = size + sp;