ch8_isa/data/
xor_data.rs

1/*
2 * xor_data.rs
3 * Defines a struct that holds data for the XOR 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 statements
24use super::Register;
25use super::super::codegen::CodeGen;
26
27/// Contextual data for the `XOR` instruction
28pub struct XorData {
29    /// The first (destination) operand
30    vx: Register,
31
32    /// The second operand
33    vy: Register 
34}
35
36//implementation
37impl XorData {
38    /// Constructs a new `XorData` instance
39    ///
40    /// # Arguments
41    ///
42    /// * `new_vx` - The first (destination) operand
43    /// * `new_vy` - The second operand
44    ///
45    /// # Panics
46    ///
47    /// This method will panic if either register is the `I` register
48    /// 
49    /// # Returns
50    ///
51    /// A new `XorData` instance with the given properties
52    pub fn new(new_vx: Register, new_vy: Register) -> XorData {
53        //validate the registers
54        if (new_vx == Register::I) || (new_vy == Register::I) {
55            panic!("Index register cannot be XORed!");
56        }
57
58        //and return an instance
59        return XorData {
60            vx: new_vx,
61            vy: new_vy 
62        };
63    }
64}
65
66//CodeGen implementation
67impl CodeGen for XorData {
68    /// Generates an opcode for the `XOR` instruction
69    /// 
70    /// # Returns
71    ///
72    /// An opcode for the `XOR` instruction from the data
73    fn gen_opcode(&self) -> u16 {
74        let mut code = 0x8003;
75        code |= (self.vx.to_id() as u16) << 8;
76        code |= (self.vy.to_id() as u16) << 4;
77        return code;
78    }
79}
80
81//unit tests
82#[cfg(test)]
83mod tests {
84    //import the XorData struct
85    use super::*;
86
87    //this test checks that the I register cannot be used
88    #[test]
89    #[should_panic]
90    fn test_cannot_xor_index() {
91        let _d1 = XorData::new(Register::I, Register::V0);
92        let _d2 = XorData::new(Register::V0, Register::I);
93    }
94
95    //this test checks opcode generation
96    #[test]
97    fn test_opcode_gen() {
98        let xord = XorData::new(Register::V1, Register::V2);
99        assert_eq!(xord.gen_opcode(), 0x8123);
100    }
101}
102
103//end of file
ch8_isa/data/xor_data.rs

ch8_isa/data/
xor_data.rs
