From ed05dd5d305e47a9b20083392f9c4760193cbc33 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20L=C3=B6ffler?= <me@fatalerrorcoded.eu>
Date: Thu, 26 Jan 2023 04:51:55 +0100
Subject: [PATCH] accumulator rotate instructions

that's the rest of the arithmetics
---
 src/emulator/instructions/arithmetic.rs | 25 +++++++++++++++++++++++++
 src/emulator/main.rs                    |  7 +++++++
 2 files changed, 32 insertions(+)

diff --git a/src/emulator/instructions/arithmetic.rs b/src/emulator/instructions/arithmetic.rs
index 6a5f77f..c5ba470 100644
--- a/src/emulator/instructions/arithmetic.rs
+++ b/src/emulator/instructions/arithmetic.rs
@@ -105,3 +105,28 @@ pub fn dcx(register: Register, state: &mut EmulatorState) {
     let (result, _) = get_register_pair(register, state).overflowing_sub(1);
     set_register_pair(register, result, state);
 }
+
+pub fn rlc(state: &mut EmulatorState) {
+    let result = state.a.rotate_left(1);
+    state.a = result;
+    state.cc.c = result & 0x01 > 0;
+}
+
+pub fn rrc(state: &mut EmulatorState) {
+    state.cc.c = state.a & 0x01 > 0;
+    state.a = state.a.rotate_right(1);
+}
+
+pub fn ral(state: &mut EmulatorState) {
+    let new_carry = state.a & 0x80 > 0;
+    let result = state.a << 1;
+    state.a = result | new_carry as u8;
+    state.cc.c = new_carry;
+}
+
+pub fn rar(state: &mut EmulatorState) {
+    let new_carry = state.a & 0x01 > 0;
+    let result = state.a >> 1;
+    state.a = result | (new_carry as u8) << 7;
+    state.cc.c = new_carry;
+}
diff --git a/src/emulator/main.rs b/src/emulator/main.rs
index 7c9fffb..0569b02 100644
--- a/src/emulator/main.rs
+++ b/src/emulator/main.rs
@@ -111,6 +111,13 @@ fn tick(state: &mut EmulatorState) {
         0x2b => arithmetic::dcx(Register::H, state),
         0x3b => arithmetic::dcx(Register::SP, state),
 
+        // Accumulator rotates
+        0x07 => arithmetic::rlc(state),
+        0x0f => arithmetic::rrc(state),
+        0x17 => arithmetic::ral(state),
+        0x1f => arithmetic::rar(state),
+
+        // Carry and complements
         0x27 => panic!("Auxiliary Carry not implemented, unable to execute DAA instruction"),
         0x2f => state.a = !state.a,       // CMA
         0x37 => state.cc.c = true,        // STC