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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::{Error, MEMORY_LENGTH};
use crate::cpu_mode::CpuMode;
use crate::state::State;
const MAX_BYTE_ADDRESS: u32 = MEMORY_LENGTH;
const MAX_HALFWORD_ADDRESS: u32 = MEMORY_LENGTH - 0x1;
const MAX_WORD_ADDRESS: u32 = MEMORY_LENGTH - 0x3;
impl State {
#[inline(always)]
#[must_use]
pub fn read_register(&self, register: u8) -> u32 {
// Limit to 0..=15.
let index = (register & 0b00001111) as usize;
return unsafe { **self.registers.get_unchecked(index) };
}
#[must_use]
pub fn read_word(&self, address: u32) -> u32 {
if address > MAX_WORD_ADDRESS { Error::OutOfBounds( address).trap(); return 0xFFFFFFFF; }
if address % 0x4 != 0x0 { Error::BadAlignment(address, 0x4).trap(); return 0xFFFFFFFF; }
unsafe {
let pointer = (self.memory.as_ptr() as *const u8).add(address as usize) as *const u32;
return *pointer;
}
}
#[must_use]
pub fn read_halfword(&self, address: u32) -> u16 {
if address > MAX_HALFWORD_ADDRESS { Error::OutOfBounds( address).trap(); return 0xFFFF; }
if address % 0x2 != 0x0 { Error::BadAlignment(address, 0x2).trap(); return 0xFFFF; }
unsafe {
let pointer = (self.memory.as_ptr() as *const u8).add(address as usize) as *const u16;
return *pointer;
}
}
#[must_use]
pub fn read_byte(&self, address: u32) -> u8 {
if address > MAX_BYTE_ADDRESS { Error::OutOfBounds(address).trap(); return 0xFF; }
unsafe {
let pointer = (self.memory.as_ptr() as *const u8).add(address as usize);
return *pointer;
}
}
#[inline(always)]
#[must_use]
pub fn read_cpsr(&self) -> u32 {
return self.cpsr;
}
#[inline(always)]
#[must_use]
pub fn read_spsr(&self, mode: CpuMode) -> u32 {
return unsafe { *self.spsr.get_unchecked(Self::spsr_index(mode)) };
}
}
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