From 6470a28ad326b589b89b80d51f8bdba0c61dec31 Mon Sep 17 00:00:00 2001
From: Kevin Hamacher <kevin.hamacher@ruhr-uni-bochum.de>
Date: Sun, 11 Feb 2018 02:23:47 +0100
Subject: [PATCH] More instructions

---
 src/cpu.rs | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/cpu.rs b/src/cpu.rs
index 0049534..adc00c5 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -393,7 +393,7 @@ impl CPU {
                 self.set_register(d, t);
             },
             Instruction::SUB(ref d, ref r) => {
-                let t = self.get_register(d) - self.get_register(r);
+                let t = self.get_register(d).wrapping_sub(self.get_register(r));
                 let dd = self.get_register(d);
                 self.set_clear_flag(StatusFlag::Carry, t > dd);
                 self.set_clear_flag(StatusFlag::Zero, t == 0);
@@ -441,6 +441,32 @@ impl CPU {
             Instruction::LDS8(ref r, ref addr) => {
                 self.set_register(r, ram[*addr as usize]);
             },
+            Instruction::LSL(ref r) => {
+                let v = self.get_register(r);
+                self.set_clear_flag(StatusFlag::Carry, v & 0x80 == 0x80);
+                self.set_register(r, v << 1);
+                self.set_clear_flag(StatusFlag::Zero, (v << 1) == 0);
+            },
+            Instruction::ROL(ref r) => {
+                let v = self.get_register(r);
+                let c = if self.test_flag(StatusFlag::Carry) { 1 } else { 0 };
+                self.set_clear_flag(StatusFlag::Carry, v & 0x80 == 0x80);
+                self.set_register(r, v << 1 | c);
+                self.set_clear_flag(StatusFlag::Zero, (v << 1) | c == 0);
+            },
+            Instruction::LSR(ref r) => {
+                let v = self.get_register(r);
+                self.set_clear_flag(StatusFlag::Carry, v & 1 == 1);
+                self.set_register(r, v >> 1);
+                self.set_clear_flag(StatusFlag::Zero, (v >> 1) == 0);
+            },
+            Instruction::ROR(ref r) => {
+                let v = self.get_register(r);
+                let c = if self.test_flag(StatusFlag::Carry) { 0x80 } else { 0 };
+                self.set_clear_flag(StatusFlag::Carry, v & 1 == 1);
+                self.set_register(r, v >> 1 | c);
+                self.set_clear_flag(StatusFlag::Zero, (v >> 1 | c) == 0);
+            },
             Instruction::SBRS(ref r, ref bit) => {
                 let r = self.get_register(r);
                 if (r & (1 << *bit)) > 0 {