1 files changed, 122 insertions, 0 deletions
diff --git a/src/cpu/isa_memory.rs b/src/cpu/isa_memory.rs
new file mode 100644
index 0000000..f4abecb
--- /dev/null
+++ b/src/cpu/isa_memory.rs
@@ -0,0 +1,122 @@
+/*
+	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);
+	}
+}