1 files changed, 85 insertions, 0 deletions
diff --git a/src/state/read.rs b/src/state/read.rs
new file mode 100644
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--- /dev/null
+++ b/src/state/read.rs
@@ -0,0 +1,85 @@
+/*
+	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)) };
+	}
+}