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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::log;
use crate::cpu::{Cpu, take_state_mut};
impl Cpu {
pub(super) fn isa_bl(&mut self, imm: i32) {
take_state_mut!(state, self);
let link_target = state.read_register(0xF).wrapping_sub(self.instruction_size);
let mut branch_target = state.read_register(0xF).wrapping_add_signed(imm);
log!("bl {branch_target:#X}");
branch_target = branch_target.wrapping_add(self.instruction_size);
state.write_register(0xE, link_target);
state.write_register(0xF, branch_target);
}
pub(super) fn isa_bl0(&mut self, imm: i32) {
take_state_mut!(state, self);
let target = state.read_register(0xF).wrapping_add_signed(imm);
state.write_register(0xE, target);
}
pub(super) fn isa_bl1(&mut self, imm: i32) {
take_state_mut!(state, self);
let mut branch_target = state.read_register(0xE).wrapping_add_signed(imm);
let link_target = state.read_register(0xF).wrapping_sub(0x2);
log!("bl {branch_target:#X}");
state.write_register(0xE, link_target);
branch_target = branch_target.wrapping_add(0x2);
state.write_register(0xF, branch_target);
}
}
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