From 45b4ea8deaa02f359670efbdbcd44150c5604078 Mon Sep 17 00:00:00 2001
From: Lea <me@janderedev.xyz>
Date: Wed, 25 Jan 2023 15:57:31 +0100
Subject: [PATCH] add ADC

---
 src/emulator/instructions/arithmetic.rs | 27 +++++++++++++++++--------
 src/emulator/main.rs                    |  1 +
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/emulator/instructions/arithmetic.rs b/src/emulator/instructions/arithmetic.rs
index e0eaf4a..aa2df4e 100644
--- a/src/emulator/instructions/arithmetic.rs
+++ b/src/emulator/instructions/arithmetic.rs
@@ -1,21 +1,32 @@
 use crate::{EmulatorState, Register, get_register};
 
-/// Sets the condition code flags according to `result`
-fn set_cc(state: &mut EmulatorState, result: u16) {
-    state.cc.z = (result & 0xff) == 0;
-    state.cc.s = (result & 0x80) == 1;
-    state.cc.c = result > 0xff;
-    state.cc.p = (result & 0xff).count_ones() % 2 == 0;
+/// Sets the condition code flags according to `result`. `flags` parameter
+/// indicates which flags will be set, 0b1111 will set all (Z, S, C, P)
+/// while 0b1000 will only set Z.
+fn set_cc(state: &mut EmulatorState, result: u16, flags: u8) {
+    if flags & 0b1000 > 0 { state.cc.z = (result & 0xff) == 0; }
+    if flags & 0b0100 > 0 { state.cc.s = (result & 0x80) > 0; }
+    if flags & 0b0010 > 0 { state.cc.c = result > 0xff; }
+    if flags & 0b0001 > 0 { state.cc.p = (result & 0xff).count_ones() % 2 == 0; }
 }
 
+/// Add values of `register` and `A`
 pub fn add(register: Register, state: &mut EmulatorState) {
     let result = get_register(register, state) + state.a as u16;
-    set_cc(state, result);
+    set_cc(state, result, 0b1111);
     state.a = (result & 0xff) as u8;
 }
 
+/// Add values of input byte and `A`
 pub fn adi(byte: u8, state: &mut EmulatorState) {
     let result = state.a as u16 + byte as u16;
-    set_cc(state, result);
+    set_cc(state, result, 0b1111);
     state.a = result as u8;
 }
+
+/// Add values of `register` and `A` and add +1 if carry bit is set
+pub fn adc(register: Register, state: &mut EmulatorState) {
+    let result = get_register(register, state) + state.a as u16 + if state.cc.c { 1 } else { 0 };
+    set_cc(state, result, 0b1111);
+    state.a = (result & 0xff) as u8;
+}
diff --git a/src/emulator/main.rs b/src/emulator/main.rs
index 624adaf..eed3021 100644
--- a/src/emulator/main.rs
+++ b/src/emulator/main.rs
@@ -124,6 +124,7 @@ fn tick(state: &mut EmulatorState) {
     match instruction {
         0x00        => {} // NOP
         0x80..=0x87 => arithmetic::add(register_from_num(instruction & 0xf), state), // ADD
+        0x88..=0x8f => arithmetic::adc(register_from_num(instruction & 0xf), state), // ADC
         0xc6        => arithmetic::adi(next_byte(), state), // ADI
         _           => not_implemented(state),
     }