diff options
Diffstat (limited to 'src/cpu/exit_exception.rs')
| -rw-r--r-- | src/cpu/exit_exception.rs | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/cpu/exit_exception.rs b/src/cpu/exit_exception.rs new file mode 100644 index 0000000..fa47fad --- /dev/null +++ b/src/cpu/exit_exception.rs @@ -0,0 +1,42 @@ +/* + 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::cpu::{Cpu, exchange, take_state_mut}; +use crate::cpu_mode::CpuMode; + +impl Cpu { + pub(super) fn exit_exception(&mut self) { + take_state_mut!(state, self); + + let cpsr = state.read_cpsr(); + let old_mode = CpuMode::from_raw((cpsr & 0b00000000000000000000000000011111) as u8); + + let spsr = state.read_spsr(old_mode); + let new_mode = CpuMode::from_raw((spsr & 0b00000000000000000000000000011111) as u8); + + let t = spsr & 0b00000000000000000000000000100000 != 0x0; + state.write_cpsr(spsr); + state.bank(new_mode); + exchange!(self, t); + } +} |