From 183634edb316cf2f1c214d962d1b7dc212a65842 Mon Sep 17 00:00:00 2001
From: Cassie Jones <code@witchoflight.com>
Date: Fri, 10 Jan 2020 22:03:02 -0500
Subject: [PATCH] Start adding the toolchain

The toolchain project will include an instruction set simulator, an
assembler, etc.
---
 toolchain/.gitignore  |  1 +
 toolchain/Cargo.lock  |  5 ++++
 toolchain/Cargo.toml  |  9 ++++++
 toolchain/src/cpu.rs  | 52 ++++++++++++++++++++++++++++++++
 toolchain/src/inst.rs | 69 +++++++++++++++++++++++++++++++++++++++++++
 toolchain/src/main.rs |  6 ++++
 6 files changed, 142 insertions(+)
 create mode 100644 toolchain/.gitignore
 create mode 100644 toolchain/Cargo.lock
 create mode 100644 toolchain/Cargo.toml
 create mode 100644 toolchain/src/cpu.rs
 create mode 100644 toolchain/src/inst.rs
 create mode 100644 toolchain/src/main.rs

diff --git a/toolchain/.gitignore b/toolchain/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/toolchain/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/toolchain/Cargo.lock b/toolchain/Cargo.lock
new file mode 100644
index 0000000..e24cc9f
--- /dev/null
+++ b/toolchain/Cargo.lock
@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "toolchain"
+version = "0.1.0"
diff --git a/toolchain/Cargo.toml b/toolchain/Cargo.toml
new file mode 100644
index 0000000..e910a73
--- /dev/null
+++ b/toolchain/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "toolchain"
+version = "0.1.0"
+authors = ["Cassie Jones <code@witchoflight.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/toolchain/src/cpu.rs b/toolchain/src/cpu.rs
new file mode 100644
index 0000000..42be7ad
--- /dev/null
+++ b/toolchain/src/cpu.rs
@@ -0,0 +1,52 @@
+use std::ops::{Index, IndexMut};
+use crate::inst::Reg;
+
+struct RegFile {
+    values: [u8; 4],
+}
+
+impl Index<Reg> for RegFile {
+    type Output = u8;
+    fn index(&self, index: Reg) -> &u8 {
+        match index {
+            Reg::R0 => &self.values[0],
+            Reg::R1 => &self.values[1],
+            Reg::R2 => &self.values[2],
+            Reg::R3 => &self.values[3],
+        }
+    }
+}
+
+impl IndexMut<Reg> for RegFile {
+    fn index_mut(&mut self, index: Reg) -> &mut u8 {
+        match index {
+            Reg::R0 => &mut self.values[0],
+            Reg::R1 => &mut self.values[1],
+            Reg::R2 => &mut self.values[2],
+            Reg::R3 => &mut self.values[3],
+        }
+    }
+}
+
+pub struct Cpu {
+    pc: u16,
+    reg: RegFile,
+    memory: Vec<u8>,
+}
+
+impl Cpu {
+    pub fn new() -> Self {
+        Cpu {
+            reg: RegFile { values: [0; 4] },
+            memory: vec![0; 1 << 16],
+        }
+    }
+
+    pub fn mem(&self) -> &[u8] {
+        &self.memory[..]
+    }
+
+    pub fn mem_mut(&mut self) -> &mut [u8] {
+        &mut self.memory[..]
+    }
+}
diff --git a/toolchain/src/inst.rs b/toolchain/src/inst.rs
new file mode 100644
index 0000000..2075230
--- /dev/null
+++ b/toolchain/src/inst.rs
@@ -0,0 +1,69 @@
+pub enum Reg {
+    R0,
+    R1,
+    R2,
+    R3,
+}
+
+pub enum RegPair {
+    R1R0,
+    R3R2,
+}
+
+pub enum Op1 {
+    Inc,
+    Dec,
+    Neg,
+    Compl,
+}
+
+pub enum OpI {
+    Add7(Imm7),
+    Sub6(Imm6),
+    Lsl(Imm3),
+    Lsr(Imm3),
+    Asr(Imm3),
+    Rol(Imm3),
+    And(Imm8),
+    Or(Imm8),
+    Xor(Imm8),
+}
+
+pub enum Op2 {
+    Add,
+    Sub,
+    And,
+    Or,
+    Xor,
+    // These are preliminary
+    Lsl,
+    Rol,
+    Bic,
+}
+
+pub struct Imm3(u8);
+pub struct Imm5(u8);
+pub struct Imm6(u8);
+pub struct Imm7(u8);
+pub struct Imm8(u8);
+
+pub enum Addr {
+    Imm(Imm7),
+    Off(Reg, Imm5),
+    One(Reg),
+    Pair(RegPair),
+}
+
+pub enum Inst {
+    Mov(Reg, Reg),
+    CallR(Reg),
+    Alu1(Reg, Op1),
+    Load(Reg, Addr),
+    Store(Addr, Reg),
+    JumpR(Reg),
+    JumpI(Imm8),
+    CallI(Imm8),
+    AluI(Reg, OpI),
+    Skip(Reg, Reg),
+    Alu2(Reg, Op2, Reg),
+}
diff --git a/toolchain/src/main.rs b/toolchain/src/main.rs
new file mode 100644
index 0000000..68e87a4
--- /dev/null
+++ b/toolchain/src/main.rs
@@ -0,0 +1,6 @@
+mod inst;
+mod cpu;
+
+fn main() {
+    println!("Hello, world!");
+}
-- 
2.43.2