ch8_isa/data/
jpc_data.rs

1/*
2 * jpc_data.rs
3 * Defines a struct that holds data for the JPC instruction
4 * Created on 12/5/2019
5 * Created by Andrew Davis
6 *
7 * Copyright (C) 2019  Andrew Davis
8 *
9 * This program is free software: you can redistribute it and/or modify   
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation, either version 3 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 * 
19 * You should have received a copy of the GNU General Public License
20 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
21 */
22
23//usage statement
24use super::super::codegen::CodeGen;
25
26/// Contextual data for the `JPC` instruction
27pub struct JpcData {
28    /// The address to jump to after adding `V0`
29    addr: u16,
30}
31
32//struct implementation
33impl JpcData {
34    /// Creates a new `JpcData` instance
35    ///
36    /// # Argument
37    ///
38    /// * `new_addr` - The address to jump to after adding `V0`
39    ///
40    /// # Returns
41    ///
42    /// A new `JpcData` instance with the given address
43    pub fn new(new_addr: u16) -> JpcData {
44        //mask the new address
45        let mask_addr = new_addr & 0x0FFF;
46
47        //and return a new instance
48        return JpcData {
49            addr: mask_addr 
50        };
51    }
52}
53
54//CodeGen implementation
55impl CodeGen for JpcData {
56    /// Generates the opcode for the instruction
57    /// 
58    /// # Returns 
59    ///
60    /// The opcode for the `JPC` instruction
61    fn gen_opcode(&self) -> u16 {
62        //return the opcode
63        return 0xB000 | self.addr;
64    }
65}
66
67//unit tests
68#[cfg(test)]
69mod tests {
70    //import the JpcData struct
71    use super::*;
72
73    //this test checks that address
74    //values are masked when a new
75    //instance is created
76    #[test]
77    fn test_address_is_masked() {
78        let data = JpcData::new(0xFFFF);
79        assert_eq!(data.addr, 0x0FFF);
80    }
81
82    //this test checks opcode generation
83    #[test]
84    fn test_opcode_gen() {
85        let jpd = JpcData::new(0x0CCC);
86        assert_eq!(jpd.gen_opcode(), 0xBCCC);
87    }
88}
89
90//end of file
ch8_isa/data/jpc_data.rs

ch8_isa/data/
jpc_data.rs
