/*
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_load_halfword(&mut self, rd: u8, rn: u8, imm: i16) {
take_state_mut!(state, self);
log!("ldrh r{rd}, [r{rn}, #{imm:#X}]");
let rn_value = state.read_register(rn);
let target = rn_value.wrapping_add_signed(imm as i32);
let result = state.read_halfword(target) as u32;
state.write_register(rd, result);
}
pub(super) fn isa_load_immediate_offset(&mut self, rd: u8, rn: u8, imm: i16) {
take_state_mut!(state, self);
let rn_value = state.read_register(rn);
let target = rn_value.wrapping_add_signed(imm as i32);
log!("ldr r{rd}, [r{rn}, #{imm:#X}] @ {target:#010X}");
let result = state.read_word(target);
state.write_register(rd, result);
}
pub(super) fn isa_load_pc(&mut self, rd: u8, imm: u16) {
// Slightly different from load_immediate_offset
// due to the target being forced word-aligned.
take_state_mut!(state, self);
let rn_value = state.read_register(0xF) & 0b11111111111111111111111111111100;
let target = rn_value.wrapping_add(imm as u32);
log!("ldr r{rd}, [pc, #{imm:#X}] @ {target:#010X}");
let result = state.read_word(target);
state.write_register(rd, result);
}
pub(super) fn isa_store_byte_immediate_offset(&mut self, rd: u8, rn: u8, imm: i16) {
log!("strb r{rd}, [r{rn}, #{imm:#X}]");
take_state_mut!(state, self);
let rn_value = state.read_register(rn);
let target = rn_value.wrapping_add_signed(imm as i32);
let result = state.read_register(rd) as u8;
state.write_byte(target, result);
}
pub(super) fn isa_store_byte_register_offset(&mut self, rd: u8, rn: u8, rm: u8) {
log!("strb r{rd}, [r{rn}, r{rm}]");
take_state_mut!(state, self);
let rn_value = state.read_register(rn);
let rm_value = state.read_register(rm);
let target = rn_value.wrapping_add(rm_value);
let result = state.read_register(rd) as u8;
state.write_byte(target, result);
}
pub(super) fn isa_store_halfword(&mut self, rd: u8, rn: u8, imm: i16) {
log!("strh r{rd}, [r{rn}, #{imm:#X}]");
take_state_mut!(state, self);
let rn_value = state.read_register(rn);
let target = rn_value.wrapping_add_signed(imm as i32);
let result = state.read_register(rd) as u16;
state.write_halfword(target, result);
}
pub(super) fn isa_store_immediate_offset(&mut self, rd: u8, rn: u8, imm: i16) {
log!("str r{rd}, [r{rn}, #{imm:#X}]");
take_state_mut!(state, self);
let rn_value = state.read_register(rn);
let target = rn_value.wrapping_add_signed(imm as i32);
let result = state.read_register(rd);
state.write_word(target, result);
}
}
