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/*
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::{Branch, Device, Log};
impl Device {
pub fn branch(&mut self, kind: Branch) {
match kind {
Branch::Offset( offset, l) => {
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::BranchOffset(offset, self.registers[0xF] - 0x8));
},
Branch::Register(register) => {
let value = self.registers[register as usize];
self.cpsr ^= (value & 0b00000000000000000000000000000001) << 0x5;
let address = value & 0b11111111111111111111111111111110;
self.registers[0xF] = address + 0x8;
if value & 0b00000000000000000000000000000001 != 0x0 { eprintln!("switching to thumb") }
self.log(Log::BranchRegister(register, address));
},
}
}
}
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