summaryrefslogtreecommitdiff
path: root/src/luma/device/branch.rs
blob: 56547630c4cac242f57a1664e08006537cc580b0 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
/*
	Copyright 2021-2023 Gabriel Jensen.

	This file is part of Luma.

	Luma is free software: you can redistribute it 
	and/or modify it under the terms of the GNU 
	Affero General Public License as published by
	the Free Software Foundation, either version 3 
	of the License, or (at your option) any later 
	version.

	Luma is distributed in the hope that it will be 
	useful, but WITHOUT ANY WARRANTY; without even 
	the implied warranty of MERCHANTABILITY or 
	FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
	Affero General Public License for more details.

	You should have received a copy of the GNU 
	Affero General Public License along with Luma. If not, 
	see <https://www.gnu.org/licenses/>. 
*/

use crate::luma::device::{Device, Log};

impl Device {
	pub fn branch(&mut self, offset: i32, l: bool) {
		if l { // Check the l flag.
			self.registers[0xE] = self.registers[0xF] - 0x4;

			self.log(Log::Link(self.registers[0xE]));
		}

		(self.registers[0xF], _) = self.registers[0xF].overflowing_add_signed(offset + 0x8); // Add extra eight to move to the new fetch instruction.

		self.log(Log::Branch(offset, self.registers[0xF] - 0x8));
	}
}