1 /*=============================================================================
2     Copyright (c) 2001-2011 Joel de Guzman
3 
4     Distributed under the Boost Software License, Version 1.0. (See accompanying
5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 =============================================================================*/
7 #if !defined(BOOST_SPIRIT_CALC8_VM_HPP)
8 #define BOOST_SPIRIT_CALC8_VM_HPP
9 
10 #include <vector>
11 
12 namespace client
13 {
14     ///////////////////////////////////////////////////////////////////////////
15     //  The Virtual Machine
16     ///////////////////////////////////////////////////////////////////////////
17     enum byte_code
18     {
19         op_neg,         //  negate the top stack entry
20         op_add,         //  add top two stack entries
21         op_sub,         //  subtract top two stack entries
22         op_mul,         //  multiply top two stack entries
23         op_div,         //  divide top two stack entries
24 
25         op_not,         //  boolean negate the top stack entry
26         op_eq,          //  compare the top two stack entries for ==
27         op_neq,         //  compare the top two stack entries for !=
28         op_lt,          //  compare the top two stack entries for <
29         op_lte,         //  compare the top two stack entries for <=
30         op_gt,          //  compare the top two stack entries for >
31         op_gte,         //  compare the top two stack entries for >=
32 
33         op_and,         //  logical and top two stack entries
34         op_or,          //  logical or top two stack entries
35 
36         op_load,        //  load a variable
37         op_store,       //  store a variable
38 
39         op_int,         //  push constant integer into the stack
40         op_true,        //  push constant 0 into the stack
41         op_false,       //  push constant 1 into the stack
42 
43         op_jump_if,     //  jump to a relative position in the code if top stack
44                         //  evaluates to false
45         op_jump,        //  jump to a relative position in the code
46 
47         op_stk_adj,     // adjust the stack (for args and locals)
48         op_call,        // function call
49         op_return       // return from function
50     };
51 
52     class vmachine
53     {
54     public:
55 
vmachine(unsigned stackSize=4096)56         vmachine(unsigned stackSize = 4096)
57           : stack(stackSize)
58         {
59         }
60 
61         int execute(
62             std::vector<int> const& code            // the program code
63           , std::vector<int>::const_iterator pc     // program counter
64           , std::vector<int>::iterator frame_ptr    // start of arguments and locals
65         );
66 
execute(std::vector<int> const & code)67         int execute(std::vector<int> const& code)
68         {
69             return execute(code, code.begin(), stack.begin());
70         };
71 
72         std::vector<int> stack;
73     };
74 }
75 
76 #endif
77 
78